Adiposity, plasma leptin concentration and reproductive function in active and sedentary females

OBJECTIVE: Circulating leptin has recently been proposed as the peripheral signal indicating the adequacy of nutritional status for reproductive function. To test whether low plasma leptin concentration for a given degree of adiposity is associated with menstrual dysfunction, we measured plasma leptin concentration and body composition in young premenopausal women with normal or abnormal reproductive function. DESIGN: Easting plasma leptin concentration (ELISA), body composition (dual energy X-ray absorptiometry) and menstrual status (menstrual history and hormonal profile) were assessed in 34 premenopausal women characterized by different levels of physical activity. RESULTS: Body fat content and plasma leptin concentration were both reduced in women with impaired reproductive function (amenorrheic < anovulatory < eumenorrheic women). However, after adjusting plasma leptin concentration for percentage body fat, there was no independent association between leptin and menstrual function. CONCLUSION: Menstrual abnormalities in young premenopausal women seem to occur as a consequence of the linear decline in adiposity and plasma leptin concentration observed in response to inadequate nutritional status. Levels of adiposity below 15% and plasma leptin concentration below 3 ng/ml are more likely to be associated with impaired reproductive function.