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Abstract
The pharmacokinetics and pharmacodynamics of testosterone trans-4-n-butylcyclohexyl
carboxylate (Code name: 20 Aet-1), a new long-acting androgen ester, were evaluated
in castrated adult rhesus monkeys and compared with those of testosterone enanthate
(TE). A single intramuscular injection of 40 mg of 20 Aet-1 returned serum testosterone
(T) to within or close to the diurnal physiological range for 80–136 days. In contrast,
a similar dose of TE increased serum T to supraphysiological levels and the response
evoked was of short duration. The ratio of T to dihydrotestosterone (T/DHT) ratio
in monkeys treated with 20 Aet-1 was comparable to that found in control animals while
in TE-treated animals, it was highly elevated. Serum estradiol (E2) elevation by 20 Aet-1 was also of smaller magnitude compared to TE. 20-Aet-1 suppressed
LH levels from day 5 until day 115. The levels of LH on day 115 were 45.8% lower compared
to the levels on day 13 post-castration. TE suppressed LH levels from day 1–7 post-injection.
The values on day 7 were 76.6% lower compared to values on day 13 post-castration.
Thus, TE-induced suppression of LH was of shorter duration, but of greater magnitude
compared to the effect caused by 20 Aet-1. Similarly, FSH was suppressed for a longer
duration (days 21–74) by 20 Aet-1 than by TE. The results indicate that the new testosterone
ester has highly favourable pharmaco-kinetic properties and may prove to be the androgen
of choice for supplementation therapy in contraceptive regimens.
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Article info
Publication history
Accepted:
June 16,
1989
Received:
December 2,
1988
Identification
Copyright
© 1989 Published by Elsevier Inc.
