Biological Chemistry - Berezov T. T., Korovkin B. F. 1998

Hormones
Pituitary Hormones

The Pituitary Gland synthesizes A number of biologically active protein and Peptide Hormones that stimulate various PHYSIOLOGICAL AND BIOCHEMICAL processes in target Tissues (Table 8.2). Depending on the site of synthesis, Pituitary Hormones are categorized into those of the anterior, posterior, and intermediate lobes. The anterior lobe predominantly produces protein and polypeptide hormones, known as tropic hormones or tropins, due to their stimulatory effect on several other Endocrine glands. In particular, the hormone that stimulates the secretion of THYROID HORMONES is termed thyrotropin.

Class="center">Table 8.2. Pituitary hormones and major clinical syndromes associated with secretory disorders

In recent years, over 50 Peptides, termed Neuropeptides and known to regulate behavioral responses, have been isolated from animal Brain tissue. These substances have been shown to influence certain forms of behavior, learning, and memory processes, regulate Sleep, and relieve pain similarly to morphine. For instance, isolated β-endorphin (a 31-amino acid residue with a determined sequence) proved to be nearly 30 times more potent than morphine as an analgesic. Several other peptides exhibit hypnotic effects, while a 16-residue peptide that induces fear of the dark in rats was named scotophobin. A polypeptide called ameletin has been isolated, which, conversely, cures rats of their fear of the loud sound of an electric bell. Research in this direction is being intensively pursued in numerous laboratories. It is quite possible that in the near future, corresponding neuropeptides, including memory peptides, will be isolated and subsequently synthesized artificially for each specific behavioral pattern.

The following data outline the Structure AND Functions of the most important protein and peptide hormones of the pituitary gland and other endocrine glands.