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

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.

Fasting 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.

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.

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.