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Clin Endocrinol (Oxf). 1996 Dec;45(6):741-8.

Circulating inhibins and activin A during GnRH-analogue down-regulation and ovarian hyperstimulation with recombinant FSH for in-vitro fertilization-embryo transfer.

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Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, UK.



We have investigated serial changes in plasma concentrations of inhibin A, inhibin B, pro alpha C and activin A in women undergoing stimulation with recombinant FSH in 'long-protocol' down-regulated cycles of IVF treatment.


Blood samples were collected during the entire IVF treatment cycle at points coinciding with the early follicular phase of the cycle preceding treatment, pituitary down-regulation, stimulation with recombinant FSH, ovulatory triggering, and the luteal phase of the cycle. In patients who achieved conception, blood samples were also taken during the first 2 weeks of pregnancy. All samples were analysed for inhibin A, inhibin B, pro alpha C, activin A and oestradiol.


Fifteen women with normal ovarian function undergoing IVF treatment with tubal factor, mild endometriosis or idiopathic infertility.


During pituitary desensitization, both inhibin A and inhibin B were significantly (P < 0.001, P = 0.002, respectively) reduced whereas levels of pro alpha C and activin A were largely unaltered. Levels of both inhibins rose markedly (P < 0.01) during FSH stimulation and a further rise in inhibin A was detected on the day after ovulatory trigger. Levels of both inhibin A and inhibin B then fell during and after oocyte pickup and continued to fall during the luteal phase. Activin A levels rose less markedly during gonadotrophin stimulation. Statistical analysis showed a high degree of correlation between the number of follicles (> 10 mm) and serum inhibin A (r = 0.65, P < 0.01) and pro alpha C (r = 0.65, P < 0.01) concentrations during the late follicular phase.


These results indicate that ovarian production of dimeric inhibin A and B are gonadotrophin dependent, whereas activin A may have a significant gonadotrophin independent or extra-gonadal source. Inhibin A and pro alpha C may be useful markers for monitoring the effects of gonadotrophin stimulation.

[Indexed for MEDLINE]

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