Q.Briefly mention the mechanism of action of FSH.

FSH (follicle stimulating hormone) is a gonadotrophin from the anterior pituitary that acts on the gonads:

• Its release is prompted by gonadotrophin releasing hormone (GnRH) from the hypothalamus, which reaches the pituitary through the portal blood system.
• Being a protein hormone, FSH works through membrane-bound receptors on its target cells; it does not enter the cell but generates second messengers inside it.
• In males, FSH acts on the testis and, together with androgens, governs spermatogenesis. …

Follicle stimulating hormone (FSH) is one of the two gonadotrophins made by the pars distalis (anterior pituitary), and its mechanism of action links the hypothalamus, the pituitary and the gonads in sequence.

The chain begins in the brain. The hypothalamus secretes gonadotrophin releasing hormone (GnRH), which travels down the axons of its neurosecretory cells and reaches the anterior pituitary through a special portal circulatory system. GnRH stimulates the pituitary to make and release the gonadotrophins, FSH among them.

Once in the blood, FSH travels to its target tissues in the gonads. Because it is a protein hormone, it acts through membrane-bound receptors sitting on the surface of the target cells. It does not enter the cell; instead, binding to its receptor forms a hormone-receptor complex at the membrane that generates second messengers inside the cell, and these bring about the cell's response.

The effect of that response differs by sex: …