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Steroid Mechanisms of action

Rupprecht R and Holsboer F (1999) Neuroactive steroids mechanisms of action and neuropsychopharmacological perspectives. Trends Neurosci. 22 410-416. [Pg.286]

Rupprecht R, Holsboer F (1999) Neuroactive steroids mechanisms of action and neuropsy-chopharmacological perspectives. Trends Neurosci 22 410-416 Sajdyk TJ, Schober DA, Gehlert DR (2002) Neuropeptide Y receptor subtypes in the basolat-eral nucleus of the amygdala modulate anxiogenic responses in rats. Neuropharmacology 43 1165-1172... [Pg.524]

Mechanism of Action. Eew data are available that describe the effects of anaboHc steroids on protein metaboHsm even fewer data exist for assessment of direct effects of anaboHc steroids on Hpid metaboHsm in growing mminants. The lack of any consistent change in somatotropin, prolactin, insulin, or other metaboHc hormones (qv) in a total of 15 studies has been noted (1,38). [Pg.409]

Mechanism of Action. P-Agonists stimulate skeletal muscle growth by accelerating rates of fiber hypertrophy and protein synthesis, but generally do not alter muscle DNA content in parallel with the increases in protein accretion (133—135). This is in contrast to the effects of anaboHc steroids and ST on skeletal muscle growth. Both of the latter stimulate fiber hypertrophy and muscle protein synthesis, but also increase muscle DNA content coincident with increased protein accretion. Whether the P-agonists decrease muscle protein degradation is equivocal. [Pg.414]

More recently, the clavulones (not specified which ones) [134] were described to have potent effects on the spontaneous beating rate of cultured myocardial cells from fetal mouse hearts. At a concentration of 0.45 pM, clavulone had positive chronotropic action on these cells however, the character of this effect clearly differed from the positive ionotropic and negative chronotropic effects of the steroid glycoside ouabain or the drug Bay K 8644. Hence, these results suggest that the clavulones may possess a new mechanism of action in this assay system. [Pg.160]

The cellular mechanism of action of hydrocortisone, a glucocorticoid, is also related to proteins but not by the enhancement of cAMP production. Hydrocortisone is transported by simple diffusion across the membrane of the cell into the cytoplasm and binds to a specific receptor The steroid-receptor complex is activated and enters the nucleus, where it regulates transcription of specific gene sequences into ribonucleic acid (RNA). Eventually, messenger RNA (mRNA) is translated to form specific proteins in the cytoplasm that are involved in the steroid-induced cellular response. [Pg.260]

Hormonal actions on target neurons are classified in terms of cellular mechanisms of action. Hormones act either via cell-surface or intracellular receptors. Peptide hormones and amino-acid derivatives, such as epinephrine, act on cell-surface receptors that do such things as open ion-channels, cause rapid electrical responses and facilitate exocytosis of hormones or neurotransmitters. Alternatively, they activate second-messenger systems at the cell membrane, such as those involving cAMP, Ca2+/ calmodulin or phosphoinositides (see Chs 20 and 24), which leads to phosphorylation of proteins inside various parts of the target cell (Fig. 52-2A). Steroid hormones and thyroid hormone, on the other hand, act on intracellular receptors in cell nuclei to regulate gene expression and protein synthesis (Fig. 52-2B). Steroid hormones can also affect cell-surface events via receptors at or near the cell surface. [Pg.846]

Fig. 1.1. General mechanism of action of steroid hormones. Steroid hormones cross through the plasmatic membrane without apparent difficulty favored by gradient. Some, which can be considered prohormones, are metabolized and transformed into more active products. This is the case with testosterone, which becomes dihydrotestosterone (DHT) in the target tissues of androgens, through the 5-alfa-reductase enzyme. The hormone binds to the receptor, a soluble protein of the cellular cytosol that, in the absence of hormone, is found associated with other proteins (hsp90 and others) that maintain the receptor in an inactive state. The hormone-receptor bond causes the other proteins to separate and a homodimer to be formed. The homodimer is the activated form of the receptor since it is capable of recognizing the genes that depend on that steroid hormone as well as of activating its expression, which leads to the synthesis of specific proteins... Fig. 1.1. General mechanism of action of steroid hormones. Steroid hormones cross through the plasmatic membrane without apparent difficulty favored by gradient. Some, which can be considered prohormones, are metabolized and transformed into more active products. This is the case with testosterone, which becomes dihydrotestosterone (DHT) in the target tissues of androgens, through the 5-alfa-reductase enzyme. The hormone binds to the receptor, a soluble protein of the cellular cytosol that, in the absence of hormone, is found associated with other proteins (hsp90 and others) that maintain the receptor in an inactive state. The hormone-receptor bond causes the other proteins to separate and a homodimer to be formed. The homodimer is the activated form of the receptor since it is capable of recognizing the genes that depend on that steroid hormone as well as of activating its expression, which leads to the synthesis of specific proteins...
Steroid hormones regulate a very extensive assembly of functions in numerous corporal tissues. Estrogens, the steroid hormones to which the majority of this chapter is dedicated, regulate from basic functions related to reproduction, the development of the skeleton, the maintenance of arterial tension, or diverse nervous functions. The molecular studies on the mechanism of action of estrogens have set the foundations that will permit us to understand how they carry out such diverse functions in such dissimilar tissues as well as how some substances that act through the estrogen signaling pathway can exercise opposite functions in different tissues. In this respect, there are five facts of particular importance that constitute the central nucleus of this revision ... [Pg.54]

Brann DW, Hendry LH, Mahesh V (1995) Emerging diversities in the mechanism of action of steroid hormones. J Steroid Biochem Mol Biol 52 2... [Pg.56]

Edwards DP, Altaman M, DeMarzo A, Zhang Y, Weigel N, Beck CA (1995) Progesterone receptor and the mechanism of action of progesterone antagonists. J Steroid Biochem Mol Biol 53 449... [Pg.57]

Tsai MJ, O Malley BW (1994) Molecular mechanisms of action of steroid/thyroid receptor superfamiliy members. Annu Rev Biochem 63 451-486... [Pg.150]

Although some steroids have been reported to reduce the toxic effects of some insecticides, the steroid ethylestrenol decreased the rate of recovery of depressed cholinesterase activity in disulfoton- pretreated rats (Robinson et al. 1978). The exact mechanism of this interaction was not determined. Ethylestrenol alone caused a small decrease in cholinesterase activity, and, therefore, resulted in an additive effect. Rats excreted less adrenaline and more noradrenaline when given simultaneous treatments of atropine and disulfoton compared with rats given disulfoton alone (Brzezinski 1973). The mechanism of action of disulfoton on catecholamine levels may depend on acetylcholine accumulation. In the presence of atropine, the acetylcholine effect on these receptors increases the ability of atropine to liberate catecholamines. [Pg.125]

C. J. Anderson, L. J. H. Lucas, T. S. Widlanski, Molecular Recognition in Biological Systems Phosphate Esters vs. Sulfate Esters and the Mechanism of Action of Steroid Sulfatases , J. Am. Chem. Soc. 1995,117, 3889-3890. [Pg.606]

The primary chemicals of interest in chilies are capsaicinoids, namely capsaicin (0.02%) and dihydrocapsaicin (figure 8.11). Also found are flavonoids, carotenoids (capsanthin), steroid saponins (capsicidin), and ascorbic acid or vitamin C (0.2%). Capsaicin has a vanilloid chemical structure. Mechanisms of Action... [Pg.326]

The mechanism of action of CYPs is radical rather than electrophilic and the actual substitution pattern is important the role of chlorine is one of blocking rather than deactivation. Many non-steroidal anti-inflammatory drugs are substrates for the... [Pg.80]

The exact mechanism of action of steroids is not fully known. [Pg.408]

The purpose of the venom is offensive while that of a poison is defensive, which in turn influences the characteristics of the toxin. Venoms, either large or small molecules, are usually variants of essential biological molecules such as lipids, steroids, histamines or other proteins. They are often mixtures with a specific mechanism of action such as paralyzing the nervous system. Poisons are designed to teach a predator that this is not a good meal. They usually cause more localized pain to discourage a predator, but depending on the dose and sensitivity of the individual, the poison can be deadly. [Pg.158]


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See also in sourсe #XX -- [ Pg.880 , Pg.881 ]




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