Inhibin is a protein that is secreted by the cells in the ovaries of women. It acts to inhibit the secretion of FSH, a follicle-stimulating hormone by the anterior pituitary gland. In both males and females, inhibin inhibits FSH production. Inhibin A is also known as INHBA.
The mechanism, however, differs between the sexes. The function in both males and females of inhibin is that inhibits FSH production. Inhibin doesn’t inhibit the secretion of GnRH from the hypothalamus.
In males, the inhibin is secreted from the Sertoli cells, which are located in the seminiferous tubules in the testes.
In females, inhibin is produced in the placenta, corpus luteum, gonads, pituitary gland, and other organs.
Inhibin A reaches its peak in the mid-luteal phase.
There is not that much known about the mechanism of inhibin; it might involve competing with activin for binding to activin receptors.
Inhibin beta A subunit combines the alpha subunit to form a pituitary FSH secretion inhibitor. Inhibin can indicate the size of a granulosa cell tumor and can be used as a marker for primary or recurring diseases. It is shown that that beta A subunit mRNA is identical to the erythroid differentiation factor subunit mRNA and that only one gene for this mRNA exists in the human genome.
Inhibin protein is dimeric in structure and has two monomers that are linked to each other by a single disulfide bond. Inhibin and activin are derived from the same family of genes and differ in their subunit composition.
It has been shown that INHBA has been shown to interact with ACVR24. ACVR24 is an activin type 2 receptor.