CHRONOBIOLOGIC EVOLUTION OF LUTEINIZING-HORMONE SECRETION IN ADOLESCENCE - DEVELOPMENTAL PATTERNS AND SPECULATIONS ON THE ONSET OF THE POLYCYSTIC-OVARY-SYNDROME

Objective: To investigate the long-term evolution of the LH circadian profile in adolescent women with anovulatory cycles and normal or elev ated LH levels in the first evaluation. Design: Prospective controlled clinical study. Setting: Reproductive endocrinology unit of an academ ic medical center. Patient(s): Twelve healthy anovulatory adolescent g irls aged 12 to 17 years (5 subjects with high plasma LH level and 7 s ubjects with normal LH level) and four ovulatory subjects as controls. Intervention(s): Blood samples were drawn every 20 minutes for 24 hou rs beginning at 10:00 A.M. at early and late gynecologic ages. Main Ou tcome Measure(s): Luteinizing hormone, FSH, E-2, T, androstenedione, o varian volume. Result(s): In the first evaluation, the highest plasma LH levels and greatest pulse amplitude were found early in the morning in the normal-LH group and late in the afternoon in the high-LH group . Controls did not display any significant circadian variation in LII secretion. The second evaluation revealed ovulatory cycles in six of s even subjects (85.7%) in the normal-LH group with the disappearance of the circadian rhythm. Two of five (40%) patients with high LR in the first evaluation became ovulatory with a significant decrease of mean LH levels and the disappearance of the circadian rhythm. Girls of both groups who remained anovulatory still displayed the accentuated circa dian profiles that were seen at the first evaluation. Conclusion(s): A n accentuated 24-hour LH periodicity is typical of puberty but. disapp ears in adulthood. The persistence of these rhythms in persistently an ovulatory adolescents may indicate a maturational arrest. In particula r, the persistence of the high LH circadian profile with the highest v alues during the day is very similar to that found in polycystic ovary syndrome. (C) 1997 by American Society for Reproductive Medicine.