Isopentylamine

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Abstract

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Principles of method if other than guideline:

The influence of a number of naturally occurring amines and their structural analogues has been examined on the metabolism of radiolabelled benzylamine (BZ) by the membrane bound semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Isopentylamine

EC Number:

203-526-0

EC Name:

Isopentylamine

Cas Number:

107-85-7

Molecular formula:

C5H13N

IUPAC Name:

isopentylamine

Details on test material:

- Name of test material (as cited in study report): isoamylamine

Results and discussion

Any other information on results incl. tables

The influence of a number of naturally occurring amines and their structural analogues has been examined on the metabolism of radiolabelled benzylamine (BZ) by the membrane bound semicarbazide-sensitive amine oxidase (SSAO) of the rat aorta.

Only primary monoamines were effective in reducing the deamination of BZ.

In the phenylethylamine series, addition of hydroxyl groups to the benzene ring decreased their potency as inhibitors while addition of a hydroxyl group at the beta position increased the inhibitory potency. Stereoselectivity of action was shown with octopamine, the L-isomer being the more active form. Kinetic analysis of these interactions showed predominantly competitive inhibition and kynuramine had the lowest Ki of 5.4 microM.

The aliphatic monoamines, isoamylamine and isobutylamine both competed with BZ. 5-Hydroxytryptamine (5-HT) was the only amine that inhibited non-competitively. Direct evidence for metabolism by SSAO of some of the competing amines such as isoamylamine, phenylethylamine, tyramine and tryptamine was obtained by fluorimetric or radiochemical assays. The inhibitors clorgyline and (E)-2-(3',4'-dimethoxyphenyl)-3-fluoroallylamine (MDL 72145) were used to characterise the amine oxidase activity responsible for the deamination. Octopamine and phenylethanolamine (PeOH) were not SSAO substrates and inhibited BZ metabolism in the fluorimetric assay. It is possible that the activity of SSAO is controlled by octopamine released from sympathetic nerve endings or 5-HT released from platelets.

Applicant's summary and conclusion

Executive summary:

Isopentylamine and isobutylamine were shown to be both substrate of the membrane-bound SSAO of the rat aorta, and competed with benzylamine (Elliot et al. 1989).

The toxicological relevance is at present unclear, but isopentylamine could also inhibit physiological substrates, and the resulting metabolites (aldehyde and hydrogen peroxide) could exert adverse effects. Defects of the rat blood vessel (aorta) were also seen with other chemicals at low levels (i.e. certain aminoalcohols), and teratogenicity of isopentylamine should therefore carefully examined.