AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 6 1208-R1211, Copyright © 1986 by American Physiological Society
Olfactory bulbectomy prevents anti-gonadal effect of exogenous melatonin in male hamsters
D. R. Pieper, D. A. Stone, R. L. Alexander and M. G. Subramanian
When male Golden hamsters are maintained on short days (less than 12.5 h of
light/day) the testes gradually regress. This testicular regression is due
to an inhibitory effect of pineal gland melatonin on gonadotropin
secretion. A previous report from the author's laboratory has indicated
that olfactory bulbectomy (BX) will prevent the testicular regression
associated with short photoperiod. The present study examined whether BX
would also prevent the testicular regression associated with exogenous
melatonin (MEL) injections. Male Golden hamsters were BX or sham (SH) BX at
23-28 days of age and were maintained on 14:10 light-dark cycle. Six weeks
following surgery, one half of each surgical group began receiving
injections of melatonin (15 micrograms sc), whereas the other half was
injected with vehicle at 1600 daily. The testes size of the SH group
injected with MEL progressively decreased, whereas the testes of all other
groups remained large. These results indicate that BX prevents the
testicular regression associated with short photoperiod by interfering with
the antigonadotropic effect of melatonin.
