IGFBP-1 - A METABOLIC SIGNAL ASSOCIATED WITH EXERCISE-INDUCED AMENORRHEA

Severe exercise in young females is a potent cause of menstrual irregu larity, although the exact pathogenesis is currently unknown. We perfo rmed a cross-sectional endocrine and metabolic analysis of a group of elite athletes and dancers in order to establish which variable, if an y, was specifically associated with changes in menstruation. By using a step-wise discriminant analysis, two independent predictors, elevate d serum cortisol and insulin-like growth factor binding protein 1 (IGF BP-1) levels, were found to account for the majority (67%) of the vari ance. IGFBP-1 is a hepatic protein which is acutely and inversely regu lated by insulin, and is thought to modulate the peripheral actions of IGF-1. While the change in serum cortisol may reflect activation of c entral stress pathways, these findings suggest for the first time that there is a second peripheral signal, IGFBP-1, which may relate the av ailability of metabolic fuels to the control of reproduction.