Voluntary exercise increases gonadotropin secretion in male golden
hamsters.
Pieper, David R., Haythem Y. Ali, Larry L. Benson, Marlon D. Shows,
Catherine A. Lobocki, and Marappa G. Subramanian.
Providence Hospital, Department of Physiology, Southfield, MI,
48037, USA and Wayne State University School of Medicine, Department
of Obstetrics and Gynecology, Detroit, MI 48201, USA
APStracts 2:0055R, 1995.
To determine the effect of voluntary exercise and food restriction on
reproductive hormone secretion, 48 adult male hamsters were placed in
cages with (EX) or without (SED) running wheels. One half of the
animals in each exercise group was fed ad libitum (AD LIB) and the
other half was food restricted (FR) to reduce their body weight to 90
g over 4 weeks. After 10 weeks, the EX AD LIB group had much larger
testes and much higher serum follicle-stimulating hormone (FSH) and
testosterone levels than the other 3 groups, but these values in the
EX FR hamsters were similar to the SED FR group. In Experiment 2,
twenty adult male hamsters were castrated and later implanted with
silastic capsules containing testosterone. Two weeks after
implantation of the capsules, the serum FSH levels were higher in the
exercise than sedentary group in the testosterone treated hamsters,
but not in animals receiving blank capsules. These data suggest that
exercise increases gonadotropin secretion by inhibiting the negative
feedback of testosterone.
Received 16 December 1994; accepted in final form 20 January
1995.
APS Manuscript Number R713-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 7 March 1995.