tailieunhanh - Color Atlas of Pharmacology (Part 22): Hormones

Hormones release of STH (and also other peptide hormones including insulin, glucagon, and gastrin). PRH: prolactin-RH remains to be characterized or established. Both TRH and vasoactive intestinal peptide (VIP) are implicated. PRIH inhibits the release of prolactin and could be identical with dopamine. Hypothalamic releasing hormones are mostly administered (parenterally) for diagnostic reasons to test AH function. Therapeutic control of AH cells. GnRH is used in hypothalamic infertility in women to stimulate FSH and LH secretion and to induce ovulation. For this purpose, it is necessary to mimic the physiologic intermittent “pulsatile” release (approx. every 90 min) by means of. | 242 Hormones Hypothalamic and Hypophyseal Hormones The endocrine system is controlled by the brain. Nerve cells of the hypothalamus synthesize and release messenger substances that regulate adenohy-pophyseal AH hormone release or are themselves secreted into the body as hormones. The latter comprise the so-called neurohypophyseal NH hormones. The axonal processes of hypothalamic neurons project to the neurohypophysis where they store the nonapeptides vasopressin antidiuretic hormone ADH and oxytocin and release them on demand into the blood. Therapeutically ADH p. 64 oxytocin p. 126 these peptide hormones are given parenterally or via the nasal mucosa. The hypothalamic releasing hormones are peptides. They reach their target cells in the AH lobe by way of a portal vascular route consisting of two serially connected capillary beds. The first of these lies in the hypophyseal stalk the second corresponds to the capillary bed of the AH lobe. Here the hypothalamic hormones diffuse from the blood to their target cells whose activity they control. Hormones released from the AH cells enter the blood in which they are distributed to peripheral organs 1 . Nomenclature of releasing hormones RH-releasing hormone RIH re-lease inhibiting hormone. GnRH gonadotropin-RH gona-dorelin stimulates the release of FSH follicle-stimulating hormone and LH luteinizing hormone . TRH thyrotropin-RH protirelin stimulates the release of TSH thyroid stimulating hormone thyrotropin . CRH corticotropin-RH stimulates the release of ACTH adrenocorticotropic hormone corticotropin . GRH growth hormone-RH soma-tocrinin stimulates the release of GH growth hormone STH somatotropic hormone . GRIH somatostatin inhibits release of STH and also other peptide hormones including insulin glucagon and gastrin . PRH prolactin-RH remains to be characterized or established. Both TRH and vasoactive intestinal peptide VIP are implicated. PRIH inhibits the release of prolactin and could be identical with dopamine. .