OLFACTORY BULBECTOMY COUNTERACTS INHIBITORY EFFECT OF FOOD RESTRICTION ON REPRODUCTIVE FUNCTION

Previous studies have shown that bilateral removal of the olfactory bu lbs (BX) results in a large increase in gonadotropin secretion in gold en hamsters. The principal question addressed by the present study was whether BX would offset the inhibitory effect of food restriction on reproductive function. BX or sham (SH) BX male golden hamsters were fe d ad libitum or were restricted to only enough food to maintain them a t 70% of the body weight of control groups fed ad libitum. The SH-70% group underwent marked testicular regression after similar to 6-8 wk, but the testes size of the BX-70% hamsters decreased only in proportio n to the decrease in body weight. The BX food-restricted group had to be fed more food to maintain the same weight as the SH-70% hamsters, a nd the BX-70% group also had a higher core body temperature, lower per cent body fat, and higher serum free thyroxine levels than SH food-res tricted animals. In summary, removal of the olfactory bulbs appears to facilitate tonic gonadotropin secretion, such that food restriction i s no longer capable of inducing testicular regression. In addition, th e olfactory bulbs may have a strong influence on metabolic function in golden hamsters.