Potassium dicyanoaurate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

3rd September 2014 to27th October 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-compliant, guideline study available as an unpublished report. No restrictions, fully adequate for assessment.

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rat

Strain:

other: CD® Crl:CD (SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at study initiation: 68 days
- Weight at study initiation: Males (MS): 337.1-369.4 g; Females (MS): 213.0-263.8 g; and Females (TX): 202.1-266.6 g. The body weight range did not exceed 20% of the mean weight for each sex at the time of selection.
- Fasting period before study: no
- Housing: MAKROLON cages type III plus (39 x 23 x 18 cm)
- Diet (e.g. ad libitum): Certified commercial diet (ssniff® R/Z V1324) provided ad libitum
- Water (e.g. ad libitum): Tap water provided ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 55 ± 15%
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): not reported

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: The test item was supplied as powder and suspended in tap water to the appropriate concentrations for administration. Test item formulations were prepared each day.

VEHICLE
- Vehicle: Tap water
- Amount of vehicle (if gavage): 5 mL/kg b.w/day
- Frequency of administration: once daily

Details on mating procedure:

Sexually mature male and female rats were randomly paired for monogamous mating:1 male and 1 female were placed in one cage during the dark period. The female was placed with the same male until pregnancy had occurred or 2 weeks had elapsed. Each morning the females were examined for the presence of sperm or a vaginal plug. If findings were negative, mating was repeated. The day of conception (day 0 of gestation) was considered to be the day on which sperm was found. This procedure was repeated until at least 8 pregnant dams were available for each group. The prematurely deceased male was replaced by another male of the same treatment group.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

For the analysis of the test item-vehicle mixtures, samples of approx. 10 mL were taken at the following times and stored at ≤ -20°C until shipment to Allessa GmbH, Germany.
- At study initiation: 9 samples were taken
- At termination of the administration period: 3 samples were taken
- Total samples: 12

The samples were labelled with the study number, test item, test species, type of sample, aliquot number, concentration, test day, sampling time and date.

Duration of treatment / exposure:

MAIN STUDY MALES (MS): Once daily, beginning 2 weeks prior to mating lasting up to the day before sacrifice until a minimum dosing period of 28 days was completed. The male rats were dosed from test day one until, and including, test day 34 and were sacrificed on test day 35.

MAIN STUDY FEMALES (MS): Once daily, beginning 2 weeks prior to mating and continuing up to, and including, day 3 post partum or the day before sacrifice. The female rats were dosed between test day one and test day 40 (first female sacrificed on test day 41) or test day 54 (last sacrificed female on test day 55).

TOXICITY FEMALES (TX): Once daily, beginning on test day 1 and continuing up to, and including, test day 43.

Frequency of treatment:

Daily

Details on study schedule:

- F1 animals were not mated
- Age at mating of the F0 mated animals in the study: not reported

Remarks:

Doses / Concentrations:
Group 1: Control (vehicle)
Basis:
nominal in water

Remarks:

Doses / Concentrations:
Group 2: 1 mg/kg b.w/day
Basis:
nominal in water

Remarks:

Doses / Concentrations:
Group 3: 3 mg/kg b.w/day
Basis:
nominal in water

Remarks:

Doses / Concentrations:
Group 4: 10 mg/kg b.w/day
Basis:
nominal in water

No. of animals per sex per dose:

NUMBER AND SEX OF ANIMALS:
- Main study (MS) 96 animals (48 males and 48 females), 12 animals per sex and group
- This was considered a sufficient number of animals to generate at least 8 pregnant females per group for evaluation of the F0-generation.
- Toxicity animals (TX): 20 female animals (5 females per dose group) were employed for toxicity assessment.

Control animals:

yes, concurrent vehicle

Details on study design:

The test item was administered in graduated doses (0, 1, 3 or 10 mg potassium dicyanoaurate/kg b.w/day) to 3 groups of males and females prior to, during and after mating to generate information concerning the effects of the test item on male and female reproductive performance such as gonadal function, mating behaviour, conception, development of the conceptus and parturition.

The dose levels were based upon the results of a dose-range-finding study in rats (LPT Study No. 30161). In the dose-ranging study, male and female rats were treated with 0.1, 1.0 and 10 mg Potassium dicyanoaurate/kg b.w/day for 14 days. As no adverse signs had been observed until test day 14, the doses were increased to 20 and 30 mg b.w/day for the formerly low and intermediate dosed animals for the following 7 test days. The control animals and the formerly high dose animals (10 mg/kg) were also treated for 7 further test days.

At the time of sacrifice or death, the animals were examined macroscopically. The adult animals were examined externally and internally. The reproductive organs and all the organs of the adult animals showing macroscopic lesions were preserved. The pups were examined externally.

Positive control:

None reported

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Animals were checked regularly throughout the working day from 7.00 am to 3.45 pm. On Saturdays and Sundays animals were checked regularly from 7.00 am to 11.00 am, with a final check performed at approximately 3.30 pm.
- Records: Dated and signed records of appearance, change and disappearance of clinical signs were maintained on clinical history sheets for individual animals.
- Cage side observations included skin/fur, eyes, mucous membranes, respiratory and circulatory systems, somatomotor activity and behaviour patterns. The onset, intensity and duration of any signs observed were recorded.

DETAILED CLINICAL OBSERVATIONS: Yes
- Individual animals were observed before and after each dosing at each time of dosing for any signs of behavioural changes, reaction to treatment or illness. Any signs of illness or reaction to treatment.
- Once before the first exposure and once a week thereafter, detailed clinical observations were made in five males from the study group and in all females of the toxicity assessment groups (five females/group).
- Clinical signs: changes in skin, fur, eyes, mucous membranes, occurrence of secretion and excretions and autonomic activity (e.g. lacrimation, pilo-erection, pupil size and unusual respiratory pattern). Changes in gait, posture and response to handling as well as the presence of clonic or tonic movements, stereotypy (e.g. excessive grooming, repetitive circling), bizarre behaviour (e.g self-mutilation, walking backwards) were also recorded.

BODY WEIGHT: Yes

FOOD EFFICIENCY: Yes
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: daily by visual appraisal

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes

CLINICAL CHEMISTRY: Yes

URINALYSIS: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
Screening of sensory reactivity to stimuli of different types (e.g. auditory, visual and proprioceptive stimuli), as well as the assessment of grip strength and motor activity assessment were conducted in males and females. The neurological screening was conducted two hours after dosing and before any blood sampling for laboratory examinations.
- Time schedule for examinations (5 randomly selected males per group): immediately prior to sacrifice on treatment day 35
- Time schedule for examination (all 5 females’ males per group): immediately prior to sacrifice on treatment day 44 (during lactation period on main study females)
- Dose groups that were examined: All dose groups
- Battery of functions tested: sensory activity, grip strength and motor activity

Oestrous cyclicity (parental animals):

Not reported

Sperm parameters (parental animals):

Detailed histopathological examination was performed on one testicle and one epididymis with special emphasis of the qualitative stages of spermatogenesis (proliferative, meiotic and spermiogenic phases) and histopathology of interstitial testicular structure of the selected male animals on the main study groups 1 and 4 following haematoxylin-eosin and PAS staining.

Litter observations:

The following parameters were evaluated:
- Number of pregnant females
- Duration of pre-coital time
- Gestation length*
* The length of gestation was calculated from day 0 of pregnancy (gestation day), until one day before lactation day (day without any signs of littering in the morning) and consistency including the day(s) of parturition.

Copora lutea
- Number per dam
- Absolute number per group
- Mean per group

Implantation sites
- Number per dam
- Distribution in the uterine horns
- Absolute number per group
- Mean per group

Live pups were counted and sexed and litters weighted. Any abnormal behaviour of the offspring was recorded.
- Number of pups absolute (at birth, 4-days post partum)
- Number of pups per dam (at birth, 4-days post partum)
- Number of stillbirths (absolute and per dam)
- Number of pups with malformations (absolute and per dam)

Postmortem examinations (parental animals):

GROSS PATHOLOGY: Yes
The male F0 animals (MS) were sacrificed on test day 39 (with the exception of the prematurely deceased animal no. 75). Dams with offspring (MS) were sacrificed on day 4 post-partum. Females showing no signs of littering were sacrificed 24 days after the last day of the mating period. Animals for female toxicity assessment (TX) were sacrificed at the same time as the majority of the female main study animals (test day 40). Animals were sacrificed by cutting the aorta abdominalis under ether anaesthesia, exsanguinated, weighed, dissected and inspected macroscopically for any abnormalities or pathological changes. Organ weights were determined for 20 adult males and 20 females, including:
- Adrenal gland (2)
- Brain
- Heart
- Kidney
- Liver
- Spleen
- Thymus

HISTOPATHOLOGY: Yes
Histopathological examinations were performed on haematoxylin-eosin-stained paraffin sections of the following organs and tissues:
- Adrenal gland (2)
- Bone marrow (os femoris)
- Brain (cerebrum, cerebellum, brain stem)
- Epididymis (2)
- Gross lesions
- Heart (left and right ventricle, septum)
- Small intestine (duodenum, jejunum, ileum, incl. Peyer’s patches, Swiss roll method)
- Intestine, large (colon, rectum)
- Kidney and ureter (2)
- Liver
- Lungs (with mainstem bronchi and bronchioles, preserved by inflation)
- Lymph node (cervical)
- Lymph node (mesenteric)
- Mammary gland (females only)
- Nerve (sciatic)
- Ovary (2)
- Seminal vesicle
- Spinal cord (3 sections)
- Spleen
- Stomach
- Testicle (2)
- Thyroid (incl. parathyroid)
- Thymus
- Tissues masses or tumours (lymph nodes)
- Trachea (incl. larynx)
- Urinary bladder
- Uterus (incl. cervix and oviducts)
- Vagina

Postmortem examinations (offspring):

MALFORMATIONS
Dead pups and pups sacrificed at day 4 post-partum were carefully examined externally for gross abnormalities. Malformations are abnormalities that are considered to have a significant adverse effects on the foetus with or without fatal consequence (EPA 1992). They are persistent structural or functional deviations outside the normal biological variation. Hence, malformations are morphological and/or functional damages, which if occurring in humans, would endanger the existence or social position. Malformations monitored included:

- Acephaly
- Acrania
- Cranioschisis
- Encephalocele
- Exencephaly
- Agnathia
- Brachygnathia
- Cleft lip
- Cleft palate
- Anal atresia
- Omphalocele
- Spina bifida
- Adactyly
- Brachydactyly
- Oligodactyly
- Polydactyly
- Acaudia
- Brachycaudia
- Rudimentary
- Agenesis
- Misalignment
- Bone fusion
- Supernumerary

Statistics:

Analysis of normal distribution and homogeneity of variances was performed using the SHAPIRO-WILKS test and the BARTLETT test. Data not normally distributed or with heterogeneous variances between the groups were stepwise log- or rank- transformed.

One-way analysis of variance (ANOVA) was performed with non-transformed or log-transformed data. The KRUSKAL-WALLIS test was used for rank-transformed data. In case of significant differences (found by ANOVA or KRUSKAL-WALLIS test), intergroup comparisons with the control group were made by parametric or non-parametric DUNNETT multiple comparison tests (p ≤0.05 and p ≤0.01).

Statistical analyses of non-parametrical data (i.e. the reproductive indices) were performed using the following settings:
FISHERs exact test, n < 100; (p ≤ 0.05 and p ≤ 0.01)
or
Chi2 test, n ≤ 0.01 (p ≤ 0.05 and p ≤ 0.01)

Reproductive indices:

The following indices were calculated for each group:

Male fertility Index [%] = (No. males with confirmed female insemination / No. rats) x 100
Female fertility Index [%] = (No. pregnant rats / No. rats) x 100
The female fertility index reflects the total number of dams that had achieved pregnancy, including dams which delivered at term, aborted or had fully resorbed litters.
Gestation Index [%] = (No. dams with live pups / No. pregnant rats) x 100

Offspring viability indices:

For each litter and group, the following indices were determined:

Birth Index [%] = (Total no. of pups born / Number of implantation sites) x 100
Live Birth Index [%] = (No. pups alive on day 0-1 of lactation / Total no. pups) x 100
Survival Index [%] = (Number of pups alive on day 4 / Number of pups alive on day 0-1) x 100
Pre-implantation loss [%] = (Corpora lutea - Implantations / corpora lutea) x 100
Post-implantation loss [%] = (Implantations - Living foetuses / Implantations) x 100

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

reduced motility, salivation

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

no effects observed

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

CLINICAL SIGNS AND MORTALITY
No premature deaths were noted in the control group and in any of the other dose groups (1, 3 or 10 mg Potassium dicyanoaurate/kg b.w/day).

MALES: No changes in behaviour, the external appearance or the faeces were noted for the male animals of the low and intermediate dose group (1 or 3 mg test item/kg b.w/day) during the pre-mating, mating and post-mating period. Treatment with 10 mg test item/kg b.w/day caused a slight reduction in motility, slight salivation and increased urination.

FEMALES: No changes in behaviour, the external appearance or the faeces were noted for the female animals treated with 1 mg test item/kg b.w/day or the control animals during the pre-mating, mating period, gestation and lactation period. At 3 mg test item/kg b.w/day, increased urination was noted in 2 females. No test-item related changes in external observations, body posture, movement and coordination or behaviour were noted for the evaluated male or female rats of the control group and the dose groups (1, 3 or 10 mg potassium dicyanoaurate/kg b.w/day).

BODY WEIGHT AND WEIGHT GAIN
MALES: No test item-related changes in body weight and body weight gain were noted for the male rats treated with 1 or 3 mg test item/kg b.w/day in comparison to the control group. The mean body weight of high dose males (10 mg test item/kg b.w/day) was marginally below the control values on days 22, 29 and 34, however, this was not deemed significant.

FEMALES: No test item-related changes in body weight and body weight gain were noted for the female toxicity rats of the treatment groups (1, 3 and 10 mg test item/kg b.w/day) in comparison to the control group. No test item-related differences in body weight and body weight gain were noted between the female rats of the control group and the female rats of the treatment groups (1, 3 and 10 mg test item/kg b.w/day) during the pre-mating period. A slight but statistically significant increase in body weight gain noted in the low dose group in the first test week (TD 1-8) showed no dose-response relationship and was considered not to be test item-related.

FOOD CONSUMPTION
No test item-related changes in food consumption were noted between the male and female rats treated with 1, 3 and 10 mg test item/kg b.w/day and controls during pre-mating.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
No test item-related changes in the consumption of drinking water was noted for the male and female rats treated with 1, 3 and 10 mg test item/kg b.w/day by visual appraisal.

HAEMATOLOGY
MALES: No test item-related effects were noted for the haematological parameters of males in the low and intermediate dose groups (1 and 3 mg test item/kg b.w/day). However, in the high male dose group (10 mg test item/kg b.w/day) slight but statistically significant reductions were noted for the haemoglobin content (11.4%, p ≤0.05) and the number of erythrocytes (14.8%, p ≤0.01) in comparison to the control group. A statistically significant increase was noted for the reticulocyte count, in addition to a slight increase in the mean corpuscular volume (MCV), leading to a slight decrease for the mean corpuscular haemoglobin concentration (MCHC).

FEMALES: No test item-related influence was noted for the haematological parameters of the low and the intermediate female dose group (1 and 3 mg test item/kg b.w/day). However, comparable to the males, high dose females presented a slight but statistically significant reduction in haemoglobin content (11.4%, p ≤0.05) and for the number of erythrocytes (14.9%, p ≤0.01). Statistically significant increased values in comparison to the controls were noted for the reticulocyte count and mean corpuscular volume, leading to a slight decrease for the mean corpuscular haemoglobin concentration (MCHC).

CLINICAL BIOCHEMISTRY
MALES: No test item-related influences on the biochemical parameters were noted for the low dose group and for the intermediate dose group (1 and 3 mg test item/kg b.w/day). At the high dose level (10 mg test item/kg b.w/day) statistically significant reductions were ntoed for the albumin concentration (10.3%, p ≤0.01) for globulin concentration (18.7%, p ≤0.05) and accordingly for the total protein concentration (14.4%, p ≤0.01). Reductions in bilirubin, creatinine and calcium concentration were not considered to be test-item related.

FEMALES: No test item related influence was noted for the examined plasma or serum levels of the biochemical parameters in any of the treatment groups (1, 3 and 10 mg test item/kg b.w/day). Statistically significant decreases in globulin concentration and an increase in the albumin: globulin ratio, decreased chloride and creatinine concentration was not considered to be test item-related. Animals in the control group presented high variability and all individual values of the high dose group were within the LPT background data.

NEUROBEHAVIOUR
No adverse effects were noted in the evaluated male or female rats in any of the treatment groups (1, 3 or 10 mg test item/kg b.w/day) during observational screening or functional screening (grip strength and spontaneous motility).

REPRODUCTIVE PERFORMANCE F0 FEMALES
At 1 and 3 mg Potassium dicyanoaurate/kg b.w/day, no test-item related differences were ntoed for the mean number of corpora lutea, implantation sites, pups born (alive and dead) and live born pups between the control group and the low and intermediate dose level groups. No test item-related differences were noted for the birth index, the live birth index and the percentages of pre- and post- implantation loss. The slight but statistically significant increase (p ≤0.05) recorded for pre-implantation loss at the intermediate dose (3 mg test item/kg b.w/day) is within the range of variability, and was not considered to be test-item related.

At the high dose (10 mg test item/kg b.w/day), the post implantation loss (14.7%, control: 4.1%) was slightly increased and the birth index (pups born alive and dead) was accordingly reduced (86.4%, control: 95.9%), both indices being statistically significantly different from the control at p≤ 0.01. A severe post-implantation loss of 68.8% was noted for one litter (loss of 11/16 implants). Decreased values compared to the controls were noted for the mean number of pups at birth (alive and dead) and accordingly the mean number of live born pups. In total, two stillbirths were noted, however these were regarded to be spontaneous and within normal variability.

SPERMATOGENESIS
No test item-related influence was noted on the qualitative stages of spermatogenesis. The histopathological examination performed on one testicle and one epididymis (with special emphasis on the qualitative stages of spermatogenesis (proliferative, meiotic and spermiogenic phases) and histopathology of the interstitial testicular structure, did not reveal any test item-related effects .


ORGAN WEIGHTS
No differences in the body weight at autopsy was noted between the control group and treatment groups (1, 3 and 10 mg test item/kg b.w/day) for the main study male and female animals. No test item related differences were noted for the relative and absolute organ weights of males. No test item related differences between the control group and the low and intermediate dose group (1 and 3 mg test item/kg b.w/day) were noted for the absolute and relative organ weights. At the high dose level (10 mg test item/kg b.w/day) increases were noted in the absolute and relative organ weight of the liver and the spleen, which were considered to be test item-related.

GROSS PATHOLOGY
MALES: Necrospy revealed no test item-related changes during the macroscopic examination of the internal organs and tissues in the male rats treated with 1 mg test item/kg b.w/day. At 3 and 10 mg test item/kg b.w/day, gastric lesions of the forestomach, confirmed to be squamous cell hyperplasia (hyperkeratosis) and stomach erosions (haemorrhages) by microscopic examination, were reported. Multiple brownish-red foci on the left side of the thymus were noted in one male of the low dose group. This change was considered a spontaneous finding.

FEMALES: No test item-related changes were noted during the macroscopic examination of the internal organs and tissues in the female rats treated with 1 or 3 mg test item/kg b.w/day. At 10 mg test item/kg b.w/day, gastric lesions (forestomach) were noted in four females. These macroscopic changes were confirmed to be squamous cell hyperplasia (hyperkeratosis) by microscopic examination. Necropsy revealed a cystic left ovary in one high dose dam (filled with clear liquid) and in the non-pregnant control, these changes were considered to be spontaneous.

HISTOPATHOLOGY
MALES: No test item-related influence was noted on the qualitative stages of spermatogenesis. The histopathological examination performed on one testicle and one epididymis and histopathology of the interstitial testicular structure did not reveal any test item-related effects. Microscopic changes were noted for the forestomach (non-glandular mucosa: squamous cell hyperplasia/hyperkeratosis) in all animals at 3 and 10 mg test item/kg b.w/day and for the stomach erosions/haemorrhages. These lesions are considered to be test item-related.

FEMALES: Microscopic changes were noted for the forestomach (squamous cell hyperplasia/hyperkeratosis) for all females treated with 3 and 10 mg test item/kg b.w/day) and for the stomach erosions in all toxicity females treated with 10 mg test item/kg b.w/day. These lesions were associated with macroscopic findings and are considered to be test item-related.

Dose descriptor:

NOAEL

Effect level:

3 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Systemic toxicity

Dose descriptor:

NOAEL

Effect level:

3 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Fertility and reproduction parameters

Clinical signs:

no effects observed

Description (incidence and severity):

However, observations were limited and for 4 days only

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

MORTALITY (SURVIVAL INDEX)
No test item-related differences were noted between the survival index of the pups from the dams of the control group and the pups from the dams treated with 1, 3 or 10 mg Potassium dicyanoaurate/kg b.w/day. All pups, excluding one cannibalised pup of the low dose group, survived until lactation day 4. Survival indices were near 100.0% for all dose groups.

BODY WEIGHT
No test item-related difference was noted between the mean or total body weights of pups from the control group and pups from the dams treated with 1, 3 or 10 mg test item/kg b.w/da on lactation days 1 and 4. No runts were noted in the control or dose groups.

GROSS PATHOLOGY (EXTERNAL EXAMINATION)
No gross abnormalities (e.g. malformations) were noted during the macroscopic external examination of the control pups and the pups from the dams treated with 1, 3 and 10 mg Potassium dicyanoaurate/kg b.w/day after sacrifice on lactation day 4.

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Development of the pups

Reproductive effects observed:

not specified

Summary of Results for Reproductive Indices (F0 Females):

Mean number per dam	Group 1 (control)	Group 2 1 mg/kg b.w/day	Group 3 3 mg/kg b.w/day	Group 4 10 mg/kg b.w/day
Corpora lutea^1	16.1	16.0	16.0	15.8
Implantation sites^1	15.6	15.1	14.8	14.8
Pups (born alive & dead)^1	15.0	14.1	14.0	12.8
Pups born alive^1	15.0	14.4	14.0	12.6
Birth index [%]^2 3	95.9	95.6	94.4	86.4*
Live birth index [%]^2 3	100.0	100.0	100.0	98.7
Pre-implantation loss [%]^2 3	2.8	5.7	7.3	6.3
Post-implantation loss [%]^2 3	4.1	4.4	5.6	14.7*
No. of stillbirths per group	0	0	0	2

¹Statistical calculations were performed by DUNNETT or Student’s t-test (p ≤ 0.05/ p ≤ 0.01)

²Statistical calculations were performed by Chi²test (p ≤ 0.05/ p ≤ 0.01)

³The listed indices were calculated form the total number of corpora lutea, implantation sites and pups per group, according to the formulas detailed in the method.

* Statistically significant result

Conclusions:

A slight reduction in birth index was identified at the high dose group for Potassium dicyanoaurate (10 mg/kg b.w/day). However, no influences on the fertility and reproductive parameters, spermatogenesis or F1 development (survival index, body weight, gross abnormalities) were noted. The NOAELs for reproductive parameters and development were 3 and 10 mg Potassium dicyanoaurate/kg b.w/day, respectively. There is no evidence to suggest increased susceptibility to the toxicity of Potassium dicyanoaurate prior to, during and after mating.

Executive summary:

The aim of the study was to obtain information on possible effects of the test item, Potassium dicyanoaurate (0, 1, 3 or 10 mg/kg b.w/day) on reproduction and development following repeated oral administration to CD® Crl:CD (SD) rats, in a GLP compliant OECD Test Guideline 422 study. The test item was administered in graduated doses to 3 groups of males and females prior to, during and after mating to generate limited information concerning the effects of the test item on gonadal function, mating behaviour, conception, development of the conceptus and parturition. At sacrifice, animals (F0/P) were examined macroscopically, microscopically and via clinical biochemistry. The pups (F1) were only examined externally.

 

No premature deaths were noted, however, Potassium dicyanoaurate treated rats demonstrated signs of systemic toxicity at 10 mg/kg b.w/day. Autopsy revealed gastric lesions at concentrations of Potassium dicyanoaurate >3 mg/kg b.w/day, which were confirmed by histopathological examination (squamous cell hyperplasia, hyperkeratosis, erosions, haemorrhages). These findings are considered to be local irritant effects and are not indicative of systemic toxicity. The NOAEL was set at 3 mg Potassium dicyanoaurate/kg b.w/day.

The qualitative sperm staging revealed no test item-related spermatogenic changes. No test item-related influences were noted on the fertility, pre-coital time or gestation length of rats treated with Potassium dicyanoaurate (1, 3 or 10 mg/kg b.w/day). At 10 mg Potassium dicyanoaurate/kg b.w/day, statistically significant increases in post-implantation loss (14.7%, control 4.1%) and reductions in birth index (86.4%, relative to 95.9%), were noted. No other differences were noted in reproductive parameters, between the control and treatment groups. No test item-related influence was noted on the survival indices, body weight or external morphology of F1 pups.

The NOAEL for fertility and reproductive parameters was set at 3 mg Potassium dicyanoaurate/kg b.w/day

The NOAEL for development of pups was set at 10 mg Potassium dicyanoaurate/kg b.w/day.

Observations of general toxicity for Potassium dicyanoaurate, such as local irritation of the forestomach and in gastroinstestinal, were detected at lower concentrations that those that may influence reproductive performance or F1 development. The results suggest that the NOAEL for systemic toxicity (3 mg Potassium dicyanoaurate/kg b.w/day) is protective for reproductive and developmental toxicity.

Effect on fertility: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

3 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

The study was conducted in accordance with OECD422 test guidelines and to GLP. Therefore the study was considered reliable without restrictions.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

The qualitative sperm staging revealed no test item-related spermatogenic changes. At 10 mg Potassium dicyanoaurate/kg b.w./day, a slight reduction was noted for the birth index (pups born alive and dead) and accordingly a slight increase was noted for the post-implantation loss. No influence was noted on the fertility and the reproductive parameters of the parental generation (FO-Generation) with respect to fertility, pre-coital time, gestation length, number of stillbirths, the gestation index, the fertility index and the preimplantation loss for any of the examined dose levels.

Short description of key information:
A repeat-dose oral toxicity and reproductive toxicity screening study in rats conducted in accordance with OECD422 study design.

Justification for selection of Effect on fertility via oral route:
A single guideline study (OECD422) conducted in accordance with GLP.

Effects on developmental toxicity

Description of key information

A repeat-dose oral toxicity and reproductive toxicity screening study in rats conducted in accordance with OECD422 study design.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

10 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

Measurement of survival index, body weight and gross abnormalities in F1 generation pups from the OECD422 test guideline study conducted to GLP.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

No adverse effects were noted on the development of the pups (F1-Generation) with respect to survival index, body weight, gross abnormalities.

Justification for classification or non-classification

Observations of general toxicity for Potassium dicyanoaurate, such as local irritation of the forestomach and in the gastroinstestinal tract, were detected at lower concentrations than those that may influence reproductive performance or F1 development. The results suggest that the NOAEL for systemic toxicity (3 mg Potassium dicyanoaurate/kg b.w/day) is protective for reproductive and developmental toxicity.