Leptin and reproduction: is it a critical link between adipose tissue, nutrition, and reproduction?

Exercise-associated reproductive disorders are frequently reported among recreationally active and elite female athletes. Although an association between exercise and menstrual disorders has been established, the mechanism by which exercise disrupts reproductive function remains unknown. Recent findings suggest that low energy availability rather than inadequate body fatness or exercise stress is likely the mechanism by which exercise impinges negatively on the hypothalamic-pituitary-ovarian axis in female athletes. The peripheral signal that informs the neural network of energy availability remains unknown. The identification of the adipocyte-derived ob gene product, leptin, and subsequent findings of its association with reproduction in both rodents and humans, led to speculations that it may be involved in the interactions between nutrition and reproduction. This review article focuses on leptin's role in modulating reproduction, and in particular, as a peripheral signal of nutritional status that integrates adipose tissue, nutrition, and reproduction in female athletes.