Kisspeptin-GnRH neuroscience: In hypothalamic amenorrhea (HA) due to energy deficiency (e.g., athletes), the primary neuroendocrine defect is at which level?

• A Primary ovarian failure with absent granulosa cell response to FSH
• B Suppression of hypothalamic Kiss1 neurons (kisspeptin-producing) in the arcuate nucleus, reducing GnRH pulse frequency ✓
• C Pituitary gonadotroph insensitivity to GnRH due to energy deficit-induced receptor downregulation
• D Excess prolactin secretion from hypoglycemia-induced hypothalamic dopamine depletion

Explanation

Hypothalamic amenorrhea in the context of energy deficiency (relative energy deficiency in sport — RED-S, formerly the female athlete triad) is driven by suppression of kisspeptin-neurokinin B-dynorphin (KNDy) neurons in the arcuate nucleus. Low leptin levels (due to fat mass loss) and elevated cortisol/ghrelin reduce kisspeptin signaling, which normally stimulates GnRH pulse generation. The result is low-frequency GnRH pulsatility → low FSH/LH → hypoestrogenism and anovulation. Treatment targets the underlying energy deficiency (increased caloric intake); exogenous kisspeptin is being investigated as a therapeutic agent. Pulsatile GnRH therapy (off-label) or ovulation induction with gonadotrophins can restore fertility.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

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Written and medically reviewed by the StethoPrep medical team.