Submitted January 3, 2007
Returned for revision January 21, 2007
Accepted February 27, 2007
Male Reproductive Tract
Chronic Treatment of Male Tammar Wallabies with Deslorelin
Implants During Pouch Life: Effects on Development,
Puberty, and Reproduction in Adulthood
C. A. Herbert *,
D. C. Eckery ,
T. E. Trigg ,
and
D. W. Cooper
* To whom correspondence should be addressed. E-mail: cathherbert{at}unsw.edu.au.
Abstract
This study evaluated the effects of chronic GnRH agonist
(deslorelin) treatment on sexual maturation in the male
tammar wallaby. Slow release deslorelin or placebo
implants were administered to male pouch young (n =
10/group) when they were between 180 and 200 days old
(approximately 6 months) to determine if disruption of the
pituitary-testicular axis during development could alter
the timing of sexual maturation or have long term effects
on adult reproductive function. Deslorelin treatment
caused a retardation of testicular growth and reduced
serum FSH and testosterone concentrations between 12 and
24 months of age. Maturation of the
hypothalamic-pituitary-testicular axis was also delayed in
treated animals at 13 and 19 months of age. Despite these
alterations in the pattern and timing of neuroendocrine
development, sexual maturation was not permanently blocked
in these animals and deslorelin treated animals reached
sexual maturity at the same age as treated animals, as
evidenced by a fully functional pituitary-testicular axis
and proven fertility at 25 months of age. The ability of
treated animals to reach puberty at the same time as
control animals, despite delayed maturation of the
hypothalamic-pituitary-testicular axis, suggests that
puberty in the male tammar wallaby is additionally
regulated by other, gonadotropin-independent, factors.
Key words:
Male Reproductive Tract •
Mechanisms of Hormone Action •
Gonadotropin-releasing hormone •
Puberty
