نتایج جستجو برای: steroid 17
تعداد نتایج: 315698 فیلتر نتایج به سال:
As is well known, adrenal cortex produces and secrete steroids, which originate from circulating or stored cholesterol. All corticosteroids are synthesized through a series of complicated enzymatic steps from cholesterol (Fig. 1). Corticosteroids are classified into three groups, glucocorticoids, mineralocorticoids and adrenal androgens based on their biological actions. In human adrenal cortex...
Previous studies in ovine uterine arteries have demonstrated that sex steroid hormones upregulate extracellular signal-regulated kinase 1/2 expression and downregulate the protein kinase C signaling pathway, resulting in the attenuated myogenic tone in pregnancy. The present study tested the hypothesis that chronic hypoxia during gestation inhibits the sex steroid-mediated adaptation of extrace...
The steroid hydroxylases CYP17A1 (P450c17, 17-hydroxylase/17,20-lyase) and CYP21A2 (P450c21, 21-hydroxylase) catalyze progesterone hydroxylation at one or more sites within a 2 Å radius. We probed their hydrogen atom abstraction mechanisms and regiochemical plasticity with deuterium-labeled substrates: 17-[(2)H]-pregnenolone; 17-[(2)H]-, 16α-[(2)H]-, 21,21,21-[(2)H(3)]-, and 21-[(2)H]-progester...
Plasma binding globulins bind steroid hormones and are thought to regulate hormone access to tissues. Mammals have both sex steroid binding globulin (SSBG) and corticosteroid binding globulin (CBG). Birds, however, have no detectable SSBG, leading to the early conclusion that birds have no plasma regulation of sex steroids. CBG, however, can bind androgens with relatively high affinity. In bird...
A primary role of GSTs (glutathione transferases) is detoxication of electrophilic compounds. In addition to this protective function, hGST (human GST) A3-3, a member of the Alpha class of soluble GSTs, has prominent steroid double-bond isomerase activity. The isomerase reaction is an obligatory step in the biosynthesis of steroid hormones, indicating a special role of hGST A3-3 in steroidogeni...
HYPOTHESIS Only selected patients require steroid replacement therapy following adrenalectomy. DESIGN Retrospective review. SETTINGS University tertiary care center and veterans' hospital. PATIENTS A total of 331 patients who underwent adrenalectomy by 1 surgeon (Q.-Y.D.) between April 1, 1993, and August 31, 2005. INTERVENTIONS Laparoscopic, open, and hand-assisted adrenalectomy. Stero...
Few studies have been conducted to investigate the potential contamination of groundwater from manureborne steroid hormones. The objective of this study was to monitor leaching of steroid hormones at the bottom of 2.4 m deep percolation lysimeters installed in plots treated with beef cattle manure. Soil samples were also collected from surrounding field plots. Treatments consisted of applicatio...
We developed a method for simultaneously measuring steroid hormones in very small volumes of serum, using a combination of high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA). By this method, aldosterone, cortisol, 11-deoxycortisol, estrone, estradiol, androstenedione, dehydroepiandrosterone, deoxycorticosterone, 17-hydroxyprogesterone, testosterone, pregnenolone, and proge...
Biotransformation of steroid hormones by a spontaneous interstitial cell tumor originating from a BALB/cJ mouse has been studied in vitro. Tumor tissue grown in a female host converted estrone predominantly to estradiol-17~. The same tissue transformed estradiol-17/~ to estrone to a considerably lesser extent. Incubation of the tumor tissue with androstenedione yielded testosterone as the princ...
The incubation of pregnenolone or dehydroisoandrosterone with bovine or rat adrenal homogenates leads to the formation of nonpolar metabolites of these steroids. The enzymatically prepared compounds have properties that are similar to the endogenous lipoidal derivatives of pregnenolone found in bovine adrenals (Hochberg, R. B., Bandy, L., Ponticorvo, L., and Lieberman, S. (1977) Proc. Natl. Aca...
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