FSH

Overview of Follicle-stimulating hormone (FSH)

Follicle-stimulating hormone

Structure of FSH

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Follicle-stimulating hormone (FSH), also known as follitropin, is a glycoprotein hormone involved in the regulation of the reproductive processes in both males and females. It is secreted by the anterior pituitary gland and plays a crucial role in the development of ovarian follicles in females and the process of spermatogenesis in males.

Structure

FSH is a heterodimeric glycoprotein composed of two subunits, alpha and beta. The alpha subunit is common to other pituitary hormones such as luteinizing hormone (LH) and thyroid-stimulating hormone (TSH), while the beta subunit is unique to FSH and confers its specific biological activity.

Function

In females, FSH is essential for the growth and maturation of ovarian follicles. It stimulates the granulosa cells of the ovary to produce estrogen, which is necessary for the follicular phase of the menstrual cycle. In males, FSH acts on the Sertoli cells of the testes to promote spermatogenesis, the process of sperm production.

Regulation

The secretion of FSH is regulated by the hypothalamic-pituitary-gonadal axis. The gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the anterior pituitary to release FSH. The levels of FSH are also modulated by the feedback mechanisms involving inhibin, activin, and sex steroids such as estrogen and testosterone.

Clinical Significance

Abnormal levels of FSH can indicate various reproductive disorders. Elevated FSH levels in women may suggest primary ovarian insufficiency or menopause, while low levels can be associated with hypogonadotropic hypogonadism. In men, high FSH levels may indicate testicular failure, whereas low levels can be a sign of pituitary dysfunction.

FSH is also used therapeutically in assisted reproductive technologies such as in vitro fertilization (IVF) to stimulate the ovaries to produce multiple eggs.

Measurement

FSH levels can be measured in the blood to assess reproductive health and diagnose disorders of the reproductive system. The test is often performed in conjunction with other hormone tests such as LH, estrogen, and testosterone.

Also see

• Luteinizing hormone
• Gonadotropin-releasing hormone
• Menstrual cycle
• Spermatogenesis
• In vitro fertilization