PATTERNS OF LUTEINIZING AND FOLLICLE-STIMULATING-HORMONE PULSATILITY IN MENOPAUSAL WOMEN - CORRELATION WITH PLASMA TESTOSTERONE LEVEL AND VASOMOTOR INSTABILITY EPISODES

OBJECTIVE: The purpose of this study was to test the hypothesis that s ubtle differences among postmenopausal women can be detected by carefu l analysis of plasma luteinizing hormone and follicle-stimulating horm one pulses. STUDY DESIGN: Twelve postmenopausal women not receiving es trogen therapy were admitted for continuous blood withdrawal at the ra te of 1 ml/min. Aliquots of 3 ml of pooled blood were collected every 3 minutes for 3 hours for the measurement of plasma luteinizing hormon e and follicle-stimulating hormone. Estradiol, estrone, free testoster one, androstenedione, and dihydrotestosterone were measured from poole d specimens. Concomitantly, continuous recordings of peripheral blood flow and peripheral temperature from the opposite arm were obtained to detect vasomotor instability episodes. RESULTS: Analysis of gonadotro pin pulses revealed a single pattern of plasma follicle-stimulating ho rmone but two distinct patterns of luteinizing hormone frequency and a mplitude. One group of six women had a low mean (+/-SEM) interpulse in terval frequency of 0.8 +/- 0.26 (p < 0.005) and a high mean amplitude of 18.4 +/- 1.8 IU/L (p < 0.05). The second group of six women bad a high mean interpulse interval frequency of 3.5 +/- 0.34 and a low mean amplitude of 12.2 +/- 1.8 IU/L luteinizing hormone pulses. Women with this pattern had more inter-vasomotor instability episode intervals ( 3.5 +/- 1.6) than did women with low frequency and high amplitude (1.3 +/- 0.5, p < 0.001). Women with low frequency and high amplitude puls es had higher plasma levels of estrone (266 +/- 33 nmol/L), testostero ne (2.3 +/- 0.7 mmol/L), and free testosterone (8.0 +/- 0.1 pmol/L, p < 0.05). CONCLUSION: There are subgroups of postmenopausal women with different patterns of luteinizing hormone pulsatility. This difference can be explained by higher steroid levels in women with low frequency and high amplitude pulses.