Фолликулостимулирующий гормон (ФСГ)

Follicle-stimulating hormone (FSH), also termed follitropin, is measured to assess the integrity of the hypothalamic–pituitary–gonadal axis in both sexes. The test supports evaluation of infertility alongside other gonadotropins and sex steroids, assists with assigning menstrual phase and confirming menopausal status, and helps characterize disorders of spermatogenesis. Clinicians use FSH to differentiate primary gonadal failure from central (hypothalamic or pituitary) causes of hypogonadism, to investigate precocious or delayed puberty, and to monitor response to hormone-based therapies.

FSH secretion from the anterior pituitary is driven by pulsatile gonadotropin-releasing hormone and occurs in bursts every 1–4 hours. Each pulse lasts approximately 15 minutes and raises serum FSH to 1.5–2.5 times the baseline. Circulating levels are regulated by negative feedback from sex steroids and by inhibin B, which is produced by ovarian granulosa cells in women and Sertoli cells in men. Across development, FSH is transiently elevated after birth, then declines markedly by about 6 months in boys and by 1–2 years in girls. Concentrations rise again preceding puberty, with nocturnal increases among the earliest biochemical signs of pubertal onset and parallel increases in gonadal steroid output. In women, FSH promotes follicular growth and primes granulosa cells for the luteinizing hormone (LH) surge while augmenting estradiol production. The follicular phase is characterized by FSH-dependent follicle maturation and estradiol secretion; a midcycle surge in FSH and LH precipitates ovulation. During the luteal phase, FSH supports progesterone production. Estradiol and progesterone modulate FSH synthesis via feedback. With menopause, ovarian failure reduces estradiol output, leading to sustained elevations of FSH and LH. In men, FSH supports seminiferous tubule development, enhances intratesticular testosterone availability, stimulates spermatogenesis, and increases production of androgen-binding protein by Sertoli cells. After puberty, male FSH levels are relatively stable; primary testicular failure is associated with increased FSH. Interpretation helps localize dysfunction: elevated FSH suggests primary gonadal pathology, whereas low or inappropriately normal FSH in the setting of hypogonadism points to hypothalamic or pituitary disease. Concurrent measurement of LH with FSH is routinely used in the evaluation of male and female infertility and to guide management.