Pituitary gland effect

P-Endorphin. A peptide corresponding to the 31 C-terminal amino acids of P-LPH was first discovered in camel pituitary tissue (10). This substance is P-endorphin, which exerts a potent analgesic effect by binding to cell surface receptors in the central nervous system. The sequence of P-endorphin is well conserved across species for the first 25 N-terminal amino acids. Opiates derived from plant sources, eg, heroin, morphine, opium, etc, exert their actions by interacting with the P-endorphin receptor. On a molar basis, this peptide has approximately five times the potency of morphine. Both P-endorphin and ACTH ate cosecreted from the pituitary gland. Whereas the physiologic importance of P-endorphin release into the systemic circulation is not certain, this molecule clearly has been shown to be an important neurotransmitter within the central nervous system. Endorphin has been invaluable as a research tool, but has not been clinically useful due to the avadabihty of plant-derived opiates. 

Prolactin is peptide hormone secreted by the pituitary gland. It acts on prolactin receptors in breast tissue where it stimulates production of casein and lactalbu-min. It also acts on the testes and ovaries to inhibit the effects of gonadotrophins. Since the secretion of prolactin is under tonic dopaminergic inhibition by the hypothalamus, dopamine D2-receptor antagonists... 

Routine gross and histopathologic examination of the pituitary gland did not reveal any effects in rats exposed nose-only to concentrations of endosulfan of up to 2 mg/m for 6 hours/day, 5 days/week for a total of 21 out of 29 days (Hoechst 1984c). 

Hormones have a profound effect on carbohydrate metabolism. Great interest has been aroused by reports of hormonal control of hexokinase activity by specific proteins in animal tissues.99- 100 Hexokinase action is the rate-limiting step in the uptake of D-glucose by muscle. Hexokinase is inhibited in diabetic muscle, but the inhibition can be partially reversed by insulin. A protein fraction from the anterior pituitary gland will inhibit the hexokinase of extracts of brain and muscle, and the effect of this... 

GH has a potentially wide range of therapeutic uses (Table 11.6). To date, however, its major application has been for the treatment of short stature. hGH extracted from human pituitary glands was first used to treat pituitary dwarfism (i.e. caused by suboptimal pituitary GH secretion) in 1958. It has subsequently proven effective in the treatment of short stature caused by a variety of other conditions, including ... 

There are also several reports of Li+-induced effects upon the endorphins (see ref. 162). More recently it has been shown that Li+ also enhances the activity of tyrosine aminopeptidase in rat pituitary gland [167]. This could result in changes in the levels of the enkephalins which are primarily degraded by aminopeptidases via cleavage of the tyrosine-glycine amide bond [168]. 

Terakawa N, Shimizu I, Aono T, Tanizawa O, Matsumoto K (1986) Dexamethasone inhibits the effects of oestrogen on the pituitary gland in rats. Acta Endocrinol 112 64-70... 

On the other hand, mercuric chloride decreased both spontaneous and evoked transmitter liberation at the frog neuromuscular junction [98] as well as the release of vasopressin from the pituitary gland [99] it was suggested that these effects are mediated via changes in the intracellular calcium ion concentration. 

Human growth hormone (hGH) is a polypeptide with 191 amino acids. It is secreted by the pituitary gland. This hormone stimulates the production of insulin-like growth factor-1 (IGF-1) from the liver. Most of the positive effects of hGH are mediated by the IGF-1 system, which also includes specific binding proteins. 

The only information regarding endocrine effects in animals after inhalation exposure to 1,4-dichlorobenzene is from a chronic-duration study in rats. In that study (Riley et al. 1980), no gross or histopathological effects were observed in the adrenal, thyroid, or pituitary glands of male or female rats exposed to 1,4-dichlorobenzene at air concentrations up to 490-499 ppm, 5 hours a day, 5 days a week for 76 weeks. No further information regarding endocrine effects was located. 

III.b.1.4. lodinated contrast media. When iodides or thioamides are contraindicated, the contrast media ipodate and iopanoic acid may be used to treat hyperthyroidism. These drugs rapidly inhibit conversion of T4 to T3 in the liver, kidney, brain and pituitary gland, and the effects are so rapid that they are sometimes helpful in the treatment of thyroid storm (see below). The drugs are non toxic and have prolonged effect. Precautions are similar to iodide,... 

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