Serum Inhibin B: A Direct And Precise Marker Of Ovarian Function
Dr Ashutosh Halder, Associate Professor, Department of Reproductive Biology. All India Institute of Medical Sciences, New Delhi 110029
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Background Inhibin B is a glycoprotein hormone produced mainly by granulosa cells of the ovary in early folliculogenesis. It selectively suppresses the secretion of pituitary FSH and has local paracrine actions in the gonads. Its measurement is useful for investigating female reproductive dysfunction.
Objective The objective of this study was to examine serum levels of inhibin B in the assessment of ovarian function in patient with premature ovarian failure.
Material & Method Serum from premature ovarian failure (n=34; group A), menopause (n=8; group B) and normally cycling fertile women (n=5; group C) was prospectively collected and stored at â€“80Â°C. Serum concentration of inhibin B was measured using specific solid phase sandwich ELISA. FSH level was measured using microparticle enzyme immuno assay (MEIA) for comparison. Independent sample t test was used to see the mean significance differences between groups.
Results Inhibin B level was undetectable (i.e., <15pg/ml) in group A & B women. The mean value in group C women was 51.8pg/ml (range 26-75). Respective values of FSH were 78.8miu/ml (range 25-150), 100.7miu/ml (range 62-150) & 5.96miu/ml (range 4.2-7.9). Inhibin B level was significantly lower in group A & B than group C women (p<0.0001) whereas differences were insignificant between group A and B women. Similarly FSH level was significantly higher in group A & B than group C women (p<0.0001). We found wide variation in FSH level in group A women. In 5 women FSH level was below 40miu/ml and was related to exogenous estrogen intake more than 3 months of blood sampling.
Conclusion This study demonstrated that inhibin B is a better predictor for ovarian failure than FSH and uninfluenced by exogenous estrogen intake (if taken >3 months before).