Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Natural abundance 13C NMR (at 67.9 MHz) is used to study the primary structure and dynamic behavior of the carbohydrate side chain [(Man)6(GlcNAc)2-Asn] of ribonuclease B and of the shorter carbohydrate side chain [Man(GlcNAc)2-Asn] of a modified ribonuclease B (ribonuclease Bm). A comparison of the 13C NMR spectra of ribonuclease B and of the model compounds Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man alpha 1 leads to 6 (Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc beta 1 leads to Asn (Compound A) and Man alpha 1 leads to 6(Man alpha 1 leads to 3)Man alpha 1 leads to 6(Man alpha 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4GlcNAc beta 1 leads to Asn (Compound B) indicates that the (Man)5(GlcNAc)2 configuration of Compound A is present as a core structure in ribonuclease B and that only up to about 30% of our sample of ribonuclease B has the (Man)6(GlcNAc)2 structure of Compound B. Spin-lattice relaxation times, nuclear Overhauser enhancements, and linewidths of the carbohydrate carbon resonances of ribonuclease Bm indicate that the mannose residue and the N-acetylglucosamine linked to mannose are undergoing fast internal rotation (at least as fast as the rate of overall molecular tumbling). The terminal mannose residues of ribonuclease B also exhibit fast internal rotation. A comparison of the chemical shifts of the nonprotonated aromatic carbons of ribonuclease B and ribonuclease A strongly suggests that the carbohydrate side chain of ribonuclease B has a negligible effect (overall or localized) on the conformation of bovine pancreatic ribonuclease.
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PMID:Structure and dynamic behavior of the oligosaccharide side chain of bovine pancreatic ribonuclease B. Application of carbon 13 nuclear magnetic resonance spectroscopy. 721 59

In rat skin, type IV is the major 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) isoenzyme expressed. Although types I and II 3 beta-HSD mRNAs are also present in the skin, their level of expression is about two orders of magnitude lower than that of type IV. In this study, we have investigated the control of type IV 3 beta-HSD mRNA levels as well as 3 beta-HSD enzymatic activity in hypophysectomized adult rats of both sexes. Skin 3 beta-HSD activity was measured by the conversion of [14C]-dehydroepiandrosterone into [14C]-androstenedione, whereas ribonuclease protection assay using a specific type IV cRNA probe was used to assess mRNA levels. Intact male and female rats show a similar level of skin 3 beta-HSD activity, although hypophysectomy caused opposite effects, a decrease being observed in males while an increase was observed in hypophysectomized female animals. We next studied the effects of hyperprolactinemia, corticosterone and 1-thyroxine in hypophysectomized animals. L-thyroxine was found to stimulate 3 beta-HSD expression and activity in male rats whereas no significant effect was observed on the already elevated levels in hypophysectomized female rats. Corticosterone caused an inhibition of type IV 3 beta-HSD mRNA levels and activity in both male and female animals. Hyperprolactinemia achieved by pituitary implants inserted under the kidney capsule stimulated the expression of type IV mRNA as well as 3 beta-HSD enzymatic activity in hypophysectomized male and female animals. The present data demonstrate the multihormonal regulation of 3 beta-HSD/isomerase expression and activity in the rat skin.
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PMID:Opposite effects of prolactin and corticosterone on the expression and activity of 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase in rat skin. 802 81

Prior research indicates that growth hormone (GH) cell differentiation can be induced prematurely by treatment with glucocorticoids in vitro and in vivo. However, the nature of these responses has not been fully characterized. In this study, the time course of corticosterone induction of GH-secreting cells in cultures of chicken embryonic pituitary cells, responsiveness of differentiated somatotrophs to GH secretagogues, localization of somatotroph precursor cells within the pituitary gland, and the effect of corticosterone on GH gene expression were determined to better define the involvement of glucocorticoids in somatotroph recruitment during development. Anterior pituitary cells from embryonic day 12 chicken embryos were cultured in 10(-9) M corticosterone for 4 to 48 h and were then subjected to reverse haemolytic plaque assays (RHPAs) for GH. Corticosterone treatment for as short as 16 h increased the percentage of GH cells compared with the control. When corticosterone was removed after 48 h and cells were cultured for an additional 3 days in medium alone, the percentage of GH secretors decreased but remained greater than the proportion of somatotrophs among cells that were never treated with corticosterone. To determine if prematurely differentiated somatotrophs were responsive to GH secretagogues, cells were exposed to corticosterone for 48 h and then subjected to GH RHPAs in the presence or absence of GH-releasing hormone (GHRH) or thyrotropin-releasing hormone (TRH). Approximately half of the somatotrophs induced to differentiate with corticosterone subsequently released more GH in response to GHRH and TRH than in their absence. The somatotroph precursor cells were localized within the anterior pituitary by culturing cells from the caudal lobe and cephalic lobe of the anterior pituitary separately. Corticosterone induction of GH cells was substantially greater in cultures derived from the caudal lobe of the anterior pituitary, where somatotroph differentiation normally occurs. GH gene expression was evaluated by ribonuclease protection assay and by in situ hybridization. Corticosterone increased GH mRNA in cultured cells by greater than fourfold. Moreover, corticosterone-induced somatotroph differentiation involved GH gene expression in cells not expressing GH mRNA previously, and the extent of somatotroph differentiation was augmented by treatment with GHRH in combination with corticosterone. We conclude that corticosterone increases the number of GH-secreting cells within 16 h, increases GH gene expression in cells formerly not expressing this gene, confers somatotroph sensitivity to GHRH and TRH, and induces GH production in a precursor population found primarily in the caudal lobe of the anterior pituitary, a site consistent with GH localization in adults. These findings support the hypothesis that glucocorticoids function to induce the final stages in the differentiation of fully functional somatotrophs from cells previously committed to this lineage.
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PMID:Somatotroph recruitment by glucocorticoids involves induction of growth hormone gene expression and secretagogue responsiveness. 1137 20

Removal of adrenal steroids by adrenalectomy (ADX) slows or reverses the development of many forms of obesity in rodents, including those that are leptin or leptin receptor deficient. Obesity is associated with hyperleptinemia and leptin resistance. We hypothesized that glucocorticoids impair leptin receptor signaling and that removal thereof would activate the Janus kinase (JAK)-signal transducers and activators of transcription (STAT) signaling pathway. The inhibitory effect of leptin (2.5 microg icv) on food intake was enhanced in ADX rats. A combination of ribonuclease protection assays, RT-PCR, Western blots, and mobility shift assays was used to evaluate the leptin signaling pathway in whole hypothalami from sham-operated, ADX and corticosterone-replaced ADX (ADX-R) Sprague-Dawley rats that were treated acutely with either saline vehicle or leptin intracerebroventricularly. ADX increased the expression of leptin receptor mRNA, increased STAT-3 mRNA and protein levels, induced constitutive STAT-3 phosphorylation and DNA binding activity, and also reduced suppressor of cytokine signaling-3 (SOCS-3) mRNA and protein levels. ADX and leptin treatment increased STAT-3 phosphorylation, but with no concomitant increase in DNA binding activity. Leptin and ADX decreased NPY mRNA expression, but their combination did not further decrease NPY mRNA. Corticosterone supplementation of ADX rats partially reversed many of these effects. In conclusion, ADX through activation of STAT-3 and inhibition of SOCS-3 activates the JAK-STAT signaling pathway. These effects most probably explain the ability to prevent the development of obesity by removal of adrenal steroids.
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PMID:Constitutive activation of STAT-3 and downregulation of SOCS-3 expression induced by adrenalectomy. 1170 92