BIOACTIVE LH IN WOMEN WITH POLYCYSTIC OVARIES AND THE EFFECT OF GONADOTROPHIN SUPPRESSION

Publisher Website
Google Scholar
Abstract
Discrepancies between levels of bioactive LH (B‐LH) and immunoreactive LH (5‐LH) in polycystic ovarian syndrome (PCO) have been reported previously. Serum levels of I‐LH, B‐LH (by dispersed Leydig cell assay), FSH, oestradiol (E2) and progesterone (Prog) were measured once to three times weekly over 4 weeks in 13 women with classical clinical, ultrasound and endocrine features of PCO. Eleven women attending for infertility but whose profiles when studied three times weekly by combined endocrine and ultrasound assessment were normal and ovulatory served as controls. Seven of the women with PCO were evaluated during and after 3 weeks suppression with ethinyloestradiol (30 μg) plus 150 μg either of desogestrel or levonorgestrel; two were given both treatments. Both I‐LH and B‐LH levels were higher in PCO patients (20 ± SD 5 U/l and 46 ± 9 U/l respectively, P< 0.0001), compared with all phases of the normal cycles except the mid‐cycle peak. The B‐LH to I‐LH (B: I LH) ratio in PCO patients (2.5 ± 0.7) was higher than in all the control cycle phases (P < 0.05). I‐LH, B‐LH, B: I LH ratio, FSH and E2 were all suppressed from the second week of oestrogen‐progestogen treatment (PP < 001) at 2.3 ± 0.7. Significant correlations were found between I‐LH and B‐LH (P2 levels and B:I LH ratio (P<005). We conclude that the abnormal B: I LH ratio in PCO is reversed by suppression with sex steroids, suggesting that qualitatively abnormal LH circulating in this condition is a secondary rather than a primary abnormality.