Abstract:
Investigates the effects of caloric deprivation and stress induction on the reproductive physiology of the female rat. The latency of resumed oestrous cycling and associated body weight changes were investigated with rats on different rehabilitation regimens. It was found that the mechanisms regulating the oestrous cycle were resistant to relatively severe caloric deprivation. Nutritionally induced anoestrus was readily reversible with no evidence of permanent damage to the reproductive system, but the resumption of oestrous cycles was dependent upon weight gain. The results of pharmacological studies suggest that the hypothalamus is the primary site of dysfunction in anoestrous rats. The study also examines stress induction with fully fed rats. Conditioned emotional response procedures were employed to investigate the effects of signalled shocks and conditioned fear on serum LH levels and reproductive function. Daily administration of unpredictable shocks succeeded in blocking oestrous cycles in 20% of rats. When three unpredictable shocks were administered daily to groups of rats during the caloric deprivation and rehabilitation phases, this hastened the onset of anoestrus during the weight loss phase and inhibited the resumption of oestrous cycles. The findings are discussed with particular reference to the aetiology of amenorrhoea in anorexia nervosa.
