Interrelations among amenorrhea, serum gonadotropins and body weight in anorexia nervosa.

Abstract

Seventeen women with anorexia nervosa were studied before and during weight gain. The mean body weight was 93.8% before onset of illness, 82.9% at the beginning of amenorrhea and 61.8% at the minimum weight, each expressed as a percentage of the standard weight (SW). Basal serum LH and FSH level were significantly low in the lower weight patients, and increased with weight gain, with a linear correlation to the percent of SW. The LH response to 100μg of LH-RH was impaired in the lower weight group, and was improved with weight gain. The LH response in those whose weight had increased to 70% or more of the SW was often excessive and the maximum levels were significantly higher than in normal women. The FSH response to LH-RH was well maintained even in the lower weight group, but the maximum response was delayed. There was a significant correlation between improvement in the LH response and weight gain, but no significant correlation was found between FSH response and body weight. Menstrual cycles were restored in some who showed 100mIU/ml or more of the maximum LH response, but no definite relationship was found between the LH or FSH response and the resumption of menstruation. Though the weights at the cessation and at the resumption of menstruation differed from case to case, the two weight levels were almost the same in each individual. These results indicate that the critical body weights for maintaining menstrual cycle are inconsistent and that the resumption of menstruation may not be accounted for only by the recovery of such a tonic regulation as seen in the responsiveness to LH-RH following weight gain but by the restoration of the individual critical weight.