Serum concentrations of dimeric inhibin during the spontaneous human menstrual cycle and after treatment with exogenous gonadotrophin.
A recently described two-site enzyme immunoassay incorporating a pre-assay oxidation step was validated and used to measure serum concentrations of dimeric inhibin in five normally cycling women and in 13 women undergoing gonadotrophin therapy. Recombinant human inhibin A (standard) gave an assay response curve which was parallel to those for human serum samples and recovery of exogenous inhibin added to serum samples before assay was quantitative (109 +/- 8%, n = 11). During the normal menstrual cycle dimeric inhibin concentration increased from 9.0 +/- 2.0 pg/ml during the early follicular phase to reach a mid-cycle peak of 55.3 +/- 11.1 pg/ml coincident with the pre-ovulatory gonadotrophin surge. After falling to 27.9 +/- 5.7 pg/ml 1 day after the luteinizing hormone surge, inhibin then rose in parallel with serum progesterone to reach a peak value of 115.6 +/- 19.3 pg/ml during the mid-luteal phase, before falling to 14.1 +/- 4.9 pg/ml by the onset of next menses. During the follicular phase, dimeric inhibin concentrations were closely correlated with those of serum oestradiol (r = 0.69; P < 0.001), whereas during the luteal phase they were most closely correlated with serum progesterone concentrations (r = 0.73; P < 0.001). Daily treatment with human menopausal gonadotrophin promoted a progressive increase in serum dimeric inhibin concentration which increased approximately 20-fold in 6 days. In the same period total alpha-inhibin (measured by radioimmunoassay) increased approximately 5-fold, while serum oestradiol increased approximately 30-fold.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Biochemistry and Physiology, University of Reading, UK.
S
S
Muttukrishna
P A
PA
Fowler
N P
NP
Groome
G G
GG
Mitchell
W R
WR
Robertson
P G
PG
Knight
D000328:Adult; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015571:Follicular Fluid / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007247:Infertility, Female / Q000097:blood / Q000188:drug therapy / Q000378:metabolism; D007265:Inhibins / Q000097:blood* / Q000737:chemistry / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood; D008596:Menotropins / Q000494:pharmacology*; D008597:Menstrual Cycle / Q000097:blood* / Q000378:metabolism; D010062:Ovulation Induction; D011374:Progesterone / Q000097:blood; D011487:Protein Conformation; D015203:Reproducibility of Results
D011374:Progesterone; D004958:Estradiol; D007265:Inhibins; D008596:Menotropins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone