Hormones stimulatory

Takahara J, Yunoki S, Yakushiji W, et ah Stimulatory effects of gamma-hydroxybutyric acid on growth hormone and prolactin release in humans. J Clin Endocrinol Metab 44 1014-1017, 1977... 

Other oncogenes code for proteins that bind guanine nucleotides, and others code for nuclear proteins. The guanine nucleotide-binding proteins, the so-called G proteins, affect several key reactions. Some G proteins are stimulatory, whereas others are inhibitory. For example, they link hormone receptors to adenylate cyclase, they translocate... 

Somatostatin (SOM), initially identified by its ability to inhibit the release of growth hormone, is known to have inhibitory effects on a variety of cells [ 109], In mast cells and in basophils, SOM, like NT, has inhibitory as well as stimulatory effects depending on the concentration used. At high concentrations (> 10 8 M), SOM is a powerful stimulus of peritoneal mast-cell secretion (from both normal and athymic rats) and resembles other non-immunologic secretagogues such as compound 48/80, SP and NT in that it triggers a rapid exocytosis that is primarily dependent on cellular Ca [ 110,111], A similar effect is seen in vivo when injected into skin or skin blisters at high concentrations (> 10-8 M), SOM causes a rapid, dose-dependent release of histamine [88, 112] but when used at concentrations lower than those which elicit a secretory... 

We have tested the hypothesis that insulin inhibits the stimulatory effect of parathyroid hormone (PTH) on calcium reabsorption in the distal nephron. PTH is known to enhance calcium transport in renal cells, probably by stimulation of adenylate cyclase and subsequent increases in 3 5 cyclic AMP productoin. Since insulin had been observed to inhibit PTH-stimulated increases in kidney cyclic AMP levels in vitro (24) we investigated whether insulin-mediated hypercalciuria was dependent on the presence of PTH in vivo. 

Hormesis is the term used for the phenomenon of stimulatory effects at low-level exposure, and inhibition at high-level exposure. The term derives from the Greek word Hormo which means excite or set in motion, and which is also the root of the word hormone. The concept of hormesis dates back to the 1920s. A substance showing hormesis has the opposite effect in small doses compared to effects at large doses. The definition of hormesis does not imply that low-dose effects are necessarily beneficial, only that they are opposite to high-dose effects. 

One of the principles of the use of hormones in oncology is based on the fact that the growth of tumors which occur in hormone-sensitive tissues may be inhibited by hormones with opposing actions, by hormone antagonists, or by agents that inhibit the synthesis of the stimulatory hormone. Other hormone treatments are based on less specific antimitotic effects. 

The actions of nicotine on the central nervous system are the result of a composite of stimulatory and depressant effects. These can include tremors, convulsions, respiratory stimulation or depression, and release of antidiuretic hormone from the pituitary. Nausea and emesis are frequently observed after the initial use of nicotine in the form of tobacco smoke. However, tolerance to these effects rapidly develops. This is in contrast to the effects of nicotine on the cardiovascular system, where tolerance develops much more slowly. 

Although used traditionally, natural hormones are less clinically desirable due to varying potencies, inconsistent clinical effects, and more adverse stimulatory effects synthetic derivatives (i.e., levothyroxine) preferred... 

The cAMP second messenger pathway. Key proteins include hormone receptors (Rec), a stimulatory G protein (Gs), catalytic adenylyl cyclase (AC), phosphodiesterases (PDE) that hydrolyze cAMP, cAMP-dependent kinases, with regulatory (R) and catalytic (C) subunits,... 

Small amounts of iodide are necessary for hormone production, but large amounts inhibit T3 and T4 production and release. Solid arrows, stimulatory influence dashed arrows, inhibitory influence. H, hypothalamus, AP, anterior pituitary. 

FIGURE 12-12 Transduction of the epinephrine signal the /J-adrenergic pathway. The seven steps of the mechanism that couples binding of epinephrine (E) to its receptor (Rec) with activation of adenylyl cyclase (AC) are discussed further in the text. The same adenylyl cyclase molecule in the plasma membrane may be regulated by a stimulatory G protein (Gs), as shown, or an inhibitory G protein (G, not shown). Gs and G, are under the influence of different hormones. Hormones that induce GTP binding to G, cause inhibition of adenylyl cyclase, resulting in lower cellular [cAMP]. 

The (3 adrenergic receptors are not coupled directly to adenylate cyclase but interact through an intermediary stimulatory protein Gs, which contains three subunits, a, P, and y.179 182 We know that the Gs protein associated with P adrenergic stimulation is only one of a very large number of related G proteins, so named because of their property of binding and hydrolyzing GTP. In its unactivated state the a subunit of a G heterotrimer carries a molecule of bound GDP. Apparently, the Gs proteins and the hormone receptors,... 

As mentioned earlier, the adenylate cyclase system is hormone sensitive and many hormones are capable of regulating the enzymes involved in either a stimulatory or an inhibitory manner, thus modulating... 

Theophylline is found in coffee and in tea in very small amounts, but it has a stronger effect on the heart and breathing than does CF. Along with CF, TP is used as a medicine to treat emphysema and bronchitis (254,255). Caffeine and TP inhibit cAMP phosphodiesterase. In their presence the effects of cAMP, and thus the stimulatory effects of the hormones that lead to its production, are prolonged and intensified. 

The suggestion of the existence of postsynaptic H3 receptors have not been clarified in relation to pituitary hormone secretion, although the finding in a single study of a stimulatory effect of the H3 receptor agonist RmHA infused centrally on PRL may suggest such an effect - in as much as the effect was prevented by THIOP. 

According to available literature 12 weeks of continuous administration are required for Avandia to reach full effects in most individuals. A note of interest is that theoretically Avandia improved the results realized from IGF-1 use as well as insulin. This is due to the cross over stimulatory effect each of these hormones has upon the opposite receptor-sites. This may have had some positive effects upon GH use since GH converts to, and triggers IGF-1 release. 

Gonadotropin A hormone that produces a stimulatory effect on the gonads (ovaries and testes) primary gonadotropins include luteinizing hormone (LH) and follicle-stimulating hormone (FSH). 

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