hypothalamusfactoren

Hypothalamusfactoren, or hypothalamic factors, are signaling molecules produced by neurons of the hypothalamus that regulate the activity of the pituitary gland, and in some cases other organs. They include releasing hormones and inhibiting hormones that control posterior and anterior pituitary secretion, as well as neurohormones released from the hypothalamus into the posterior pituitary.

Most hypothalamic factors reach the anterior pituitary via the hypothalamic–hypophyseal portal system, a network of capillaries that allows efficient transfer of signals from hypothalamic neurons to pituitary cells. The posterior pituitary receives vasopressin (antidiuretic hormone) and oxytocin directly from hypothalamic neurons for storage and release.

Key hypothalamic releasing and inhibiting hormones include:

- Thyrotropin-releasing hormone (TRH): stimulates thyroid-stimulating hormone (TSH) and prolactin.

- Gonadotropin-releasing hormone (GnRH): stimulates luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

- Corticotropin-releasing hormone (CRH): stimulates adrenocorticotropic hormone (ACTH).

- Growth hormone-releasing hormone (GHRH): stimulates growth hormone (GH).

- Somatostatin (growth hormone-inhibiting hormone, GHIH): inhibits GH and TSH.

- Dopamine (prolactin-inhibiting factor): inhibits prolactin release. Some hypothalamic factors can also modestly influence prolactin release, depending on context.

Role and regulation: Hypothalamic factors are released in response to physiological signals and environmental cues, and they regulate pituitary hormone output. Target organ hormones typically provide negative feedback to both the hypothalamus and pituitary to modulate further release.

Clinical relevance: Disorders of hypothalamic factor production or action can affect growth, reproduction, thyroid, and adrenal function. Therapeutic approaches include GnRH analogs, GHRH analogs, and dopamine agonists to correct specific hormone imbalances.