LHRH responsiveness in anorexia nervosa: intactness despite prepubertal circadian LH pattern.

Consistent with previous findings, six women with primary anorexia nervosa who underwent 24-hour endocrine studies were all observed to have immature (prepubertal or pubertal) patterns of circadian luteinizing hormone (LH) secretion. This abnormality was present despite negligible weight deficit (but active symptomatology) in three of the women. Regardless of the extent of immaturity of circadian pattern, each woman showed a completely normal release of LH in response to the single intravenous administration of luteinizing hormone releasing hormone (LHRH). These findings provide further evidence for the intactness of pituitary function and for the possibility of a functional hypothalamic disturbance in anorexia nervosa. The discrepant finding in certain other studies of inadequate LH response to LHRH in women with anorexia nervosa is reviewed, and the potential influences of differing variables in these studies and the possibility of a heterogeneous illness are emphasized.