Pituitary hormone

Pituitary hormones are mainly produced by the anterior lobe. The posterior pituitary gland does not secrete hormones. It only stores and releases the antidiuretic hormone (ADH) and oxytocin produced by the hypothalamus. Pituitary hormones are regulated by hypothalamic neurohormones and corresponding target gland hormones. The anterior pituitary gland secretes the following hormones: thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle stimulating hormone (FSH), growth hormone (GH), prolactin (PRL), LH and FSH is also known as gonadotropin (GnH). The above six are polypeptides or protein hormones having a significant physiological activity. Among them, TSH, LH and FSH are glycoproteins, each of which has α- and β-subunits, and their α-subunits are basically the same, while β-subunits are different, and most of the antigenic determinants are in them. On the specific β-subunit, but the maintenance of its biological activity requires the complete molecular structure of α-, β-binding. In the past, melanocyte stimulating hormone (MSH) was secreted in the anterior pituitary, but in chemical structure, β-MSH is a fragment (41-58 amino acids) in the β-lipotropin (β-LPH) molecule. α-MSH is also only a fragment of the amino terminus of the ACTH molecule (1st to 13th amino acids). In 1974, it was found that neither α-MSH nor β-MSH exist in normal human plasma and pituitary extracts, and may belong only to Fragments taken from macromolecules such as lipoproteins during extraction, but may be secreted by MSH in animals with significant mid-leaves. Among the anterior pituitary hormones, ACTH, TSH, LH, and FSH act on the surrounding target glands; the adrenal cortex, thyroid gland, and gonads promote the synthesis and release of the corresponding hormones. Although GH has no clear target gland, it has a growth effect on bone. It is by promoting the liver to produce a growth hormone medium (SM), also known as sulfation factor (SF) (see "Growth Hormone"), PRL acts on the mammary gland to stimulate milk secretion, and still maintains the corpus luteum in rodents. Secretion. Pituitary hormones are regulated by feedback from the hypothalamic release hormone (factor) and various target gland hormones. In addition, ACTH cells in the anterior pituitary also produce β-lipotropin, and its physiological significance is still unclear. The molecular structure contains β-MSH and some amino acid sequences of endorphins and enkephalin molecules (see “Adrenocorticotropic hormone”. And β-lipotropin”). ADH is stored in the posterior pituitary, and is secreted into the blood circulation after being stimulated by increased plasma osmotic pressure or insufficient blood volume. It mainly acts on the renal distal convoluted tubules and collecting ducts, so that the water absorption increases and the urine concentrates into hypertonic fluid, thereby regulating The total amount of water in the body, effective blood volume, osmotic pressure and blood pressure. The role of oxytocin is mainly to stimulate uterine contraction during childbirth, promote lactation after childbirth, but also has a mild antidiuretic effect.