Measurement of dimeric inhibin B throughout the human menstrual cycle.
This report describes the development of a specific and sensitive assay for inhibin B and its application to the measurement of inhibin B concentrations in plasma during the human menstrual cycle. A monoclonal antibody raised against a synthetic peptide from the betaB-subunit was combined with an antibody to an inhibin alpha-subunit sequence in a double antibody enzyme-linked immunosorbent assay format. The validated assay had a limit of detection of 10 pg/mL and 0.5% cross-reactivity with inhibin A. Using this immunoassay, we found that the plasma concentration of inhibin B rose rapidly in the early follicular phase to a peak of 85.2 +/- 9.6 pg/mL on the day after the intercycle FSH rise, then fell progressively during the remainder of the follicular phase. Two days after the midcycle LH peak, there was a short lived peak in the inhibin B concentration (133.6 +/- 31.2 pg/mL), which then fell to a low concentration (<20 pg/mL) for the remainder of the luteal phase. In contrast, the inhibin A concentration was low in the early follicular phase, rose at ovulation, and was maximal during the midluteal phase. The concentration of inhibin B in individual follicular fluid samples was 20- to 200-fold higher than the concentration of inhibin A and was highest in follicular fluid samples from the early follicular phase. Inhibin B appears to be the predominant form of inhibin in the preovulatory follicle. The different patterns of circulating inhibin B and inhibin A concentrations observed during the human menstrual cycle suggest that these forms may have different physiological roles.
Groome
N P
NP
School of Biological and Molecular Sciences, Oxford Brookes University, UK.
Illingworth
P J
PJ
O'Brien
M
M
Pai
R
R
Rodger
F E
FE
Mather
J P
JP
McNeilly
A S
AS
D000328:Adult; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000939:Epitopes / Q000032:analysis; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D015571:Follicular Fluid / Q000737:chemistry; D005498:Follicular Phase; D006801:Humans; D007265:Inhibins / Q000032:analysis / Q000097:blood*; D008183:Luteal Phase; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000097:blood* / Q000502:physiology; D008969:Molecular Sequence Data; D006080:Ovarian Follicle / Q000502:physiology; D011994:Recombinant Proteins; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D000939:Epitopes; D011994:Recombinant Proteins; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone