Serum activin A and follistatin concentrations during human pregnancy: a cross-sectional and longitudinal study.

Activin A, a dimer of the betaA-subunit of inhibin, has been shown to have multiple biological activities and sites of production. Follistatin is a high-affinity binding protein for activin, which neutralizes its activity. This study provides the first data, using a cross-sectional design, on the measurement of both these proteins in the maternal circulation of a large cohort of women (6-39 weeks of gestation, n = 2-20 women/time point) during normal pregnancies, and confirms that similar patterns are seen in nine women studied longitudinally during pregnancy.

Serum immunoactive inhibin levels in early pregnancy after in vitro fertilization and embryo transfer.

Objective: To determine the maternal serum concentrations of inhibin, E2, P, and hCG in early pregnancies arising from IVF and ET or GIFT and to assess the value of these hormone measurements in determining outcome of pregnancy.

Design: Serum immunoactive inhibin, E2, P, and hCG levels were measured in the first trimester of pregnancies after IVF-ET and GIFT procedures.

Setting: In vitro fertilization and ET or GIFT was undertaken at Monash IVF, Melbourne, Victoria, Australia.

The role of inhibin on pituitary FSH secretion and maturation of pituitary-gonadal axis in immature female rats.

The possible physiological significance of endogenous inhibin was evaluated in prepubertal female rats during sexual maturation. Ovarian/serum inhibin, serum FSH levels were measured from 4th day to 35th day of life by RIA. Serum inhibin levels were first detected on 4th day of life, thereafter, progressively increasing up to 27th day.

Inhibin and relaxin concentrations in early singleton, multiple, and failing pregnancy: relationship to gonadotropin and steroid profiles.

Objective: To examine the inter-relationships between inhibin, relaxin, steroid concentrations, estradiol (E2), progesterone (P), and gonadotropins in early pregnancy.

Design: Hormone concentrations in plasma were measured during the luteal phase of subjects who became pregnant (n = 58) or failed to become pregnant (n = 47) after ovarian hyperstimulation for in vitro fertilization-gamete intrafallopian transfer (IVF-GIFT) (group 1). A further group of subjects became pregnant (n = 7) or failed to become pregnant (n = 8) during endocrinology tracking of a natural cycle (group 2).

Circulating maternal immunoreactive inhibin levels during pregnancy in the rat: effects of oophorectomy, hypophysectomy, hemihysterectomy, delayed implantation and pseudopregnancy.

This study examines the source of inhibin in the maternal circulation of pregnant rats by measuring serum immunoactive inhibin levels following a range of experimental procedures. Ovariectomy at days 7, 13 or 19 of gestation, with maintenance of pregnancy by supplementation with progesterone and oestradiol dipropionate, led to a profound fall of serum inhibin levels in comparison with controls, demonstrating that the ovary is a major source of circulating inhibin. This conclusion was supported by the inhibition of the late rise (days 16-22) in serum inhibin in pregnant rats which were hypophysectomized on day 15 and maintained with oestrogen and progesterone supplementation.