Low levels: Enhance LH secretory response to GnRH.
Inhibit pituitary secretion of gonadotrophins, in the presence of oestrogens. Other peptide hormones involved in the hypothalamic-pituitary-ovarian feedback cycle are activin and inhibin, members of the transforming growth factor-beta superfamily of glycoproteins.
Inhibin is a heterodimer of alpha and beta sub-units linked by disulphide bonds. There are two forms, A and B. The molecular weight is 32 kDa. It is synthesised and secreted by the granulosa and luteal cells.
Activin is a homodimer of inhibin beta subunit linked by disulphide bridges. There are three types, A, B and AB. The molecular weight ranges from 26 to 28 kDa. It is synthesised by the granulosa cells.
Was this article helpful?