AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 3 568-R572, Copyright © 1993 by American Physiological Society
Decreased availability of metabolic fuels suppresses estrous behavior in Syrian hamsters
R. W. Dickerman, H. Y. Li and G. N. Wade
Department of Psychology, University of Massachusetts, Amherst 01003.
The availability of oxidizable metabolic fuels affects reproductive
physiology and behaviors in female mammals. In Syrian hamsters, 48 h of
food deprivation is sufficient to suppress secretion of gonadotropins and
ovarian steroids and to prevent the occurrence of ovulation and estrous
behavior. These experiments attempted to determine whether the
deprivation-induced suppression of lordosis is entirely due to the
disruption of ovarian steroid secretion or whether there are also changes
in behavioral responsiveness to estradiol and/or progesterone (P). Estrous
behavior was induced in ovariectomized hamsters with sequential injections
of 5 micrograms of estradiol benzoate (EB) and 200 micrograms P. Food
deprivation for 48 h, either before or just after EB treatment,
significantly suppressed the amount of time females spent in lordosis
during a 5-min test with a sexually experienced male. Treatment with an
inhibitor of glycolysis (2-deoxy-D-glucose) in combination with an
inhibitor of fatty acid oxidation (methyl palmoxirate) for 48 h mimicked
the effects of food deprivation and suppressed the amount of time spent in
lordosis after treatment with EB+P. Given alone, neither metabolic
inhibitor had an effect on lordosis. These findings indicate that
suppression of hamster estrous behavior by metabolic fuel deprivation is at
least in part due to a reduced responsiveness to estradiol and/or
progesterone. Furthermore, estrous behavior is responsive to metabolic
fuels in general. This is unlike hamster ovulatory cycles, which are
primarily responsive to glucose availability.
