Control of fertility by metabolic cues

The metabolic fuel hypothesis explains infertility in females during conditions such as famine, cold exposure, eating disorders and overexertion through exercise. Reproduction is affected by short-term metabolic changes rather than by body composition or size. For example, reproductive processes are deferred when food intake is low. The gonadotropin-releasing hormone (GnRH) mediates the effects on reproduction. Metabolic signals are detected in the viscera and caudal hindbrain and transmitted to the forebrain neurons that secrete GnRH. The inhibition of sexual behavior is due to a reduction in the ventromedial hypothalamus estrogen receptors.