LH and FSH (Luteinizing Hormone and Follicle Stimulating Hormone)

Function

Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) are gonadotropins produced by the anterior pituitary gland. They are essential for the proper functioning of the reproductive system. In women, FSH stimulates the growth of ovarian follicles before the release of an egg from one follicle at ovulation. LH triggers ovulation and helps with the production of progesterone. In men, FSH stimulates sperm production (spermatogenesis), and LH stimulates the interstitial cells of the testes to produce testosterone.

Why it is Ordered

Healthcare providers order these tests to investigate various reproductive health issues. They are standard tools for evaluating infertility in both men and women, assessing irregular menstrual cycles, and diagnosing disorders of the pituitary or hypothalamus. In children, these tests are used to evaluate precocious (early) or delayed puberty.

Associated Conditions

• Infertility: Abnormal levels can indicate ovulatory failure or low sperm count.
• Polycystic Ovary Syndrome (PCOS): Often characterized by an elevated LH to FSH ratio.
• Primary Ovarian Insufficiency (POI) or Menopause: High levels of FSH/LH as the body attempts to stimulate unresponsive ovaries.
• Hypogonadism: Low levels suggest secondary failure (pituitary/hypothalamic), while high levels suggest primary failure (testes/ovaries).
• Pituitary Adenomas: Tumors can disrupt the secretion of these hormones.