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)

During pregnancy, marked hyperplasia of the pancreatic islet cells has been observed. This effect may be mediated by the pregnancy-associated peptide hormones, placental lactogen, PRL, and GH, which were previously shown to be mitogenic to beta-cells in vitro. To study whether the responsiveness of islet cells to these hormones is regulated on the receptor level, GH and PRL receptor gene expression was studied in pancreata from male rats and virgin, pregnant, and lactating female rats and in cultured islets and insulinoma cells (RIN-5AH) in response to various hormones. The mRNA levels were quantitated by ribonuclease protection assay, using probes specific for mRNA encoding, extracellular and intracellular domains of the GH receptor, and short and long forms of the PRL receptor, respectively. Specific transcripts for the GH receptor were present in pancreas, islets, and RIN-5AH cells. Furthermore, as previously observed in RIN-5AH cells, a predominant expression of the long form of PRL receptor vs. the short form was also found in pancreas and islet cells. Male and nonpregnant female pancreas did not differ significantly in their levels of GH and PRL receptor mRNAs. On day 14 of pregnancy, increases in both GH and PRL receptor mRNA levels were observed (1.7- and 2.4-fold, respectively), and a further increase occurred in late pregnancy (day 19), when GH and PRL receptor mRNA levels were 2.7- and 3.9-fold higher than those in the nonpregnant state. mRNA levels returned toward the basal level during lactation. In the cultured islets, PRL receptor mRNA levels were markedly increased by GH and PRL (3.5- and 6.5-fold, respectively) after exposure for 24 h, whereas estradiol and testosterone had modest stimulating effects (1.8- and 1.5-fold increases, respectively). Dexamethasone induced a 2.5-fold increase in GH receptor mRNA levels, and a weak stimulatory effect was also observed for progesterone. In RIN-5AH cells, the effect of dexamethasone on GH receptor mRNA was detectable after 2 h and maximal after 16 h. In contrast, the effects of GH and PRL on PRL receptor mRNA required 24-48 h of exposure. The effective doses were within the physiological ranges. In conclusion, these results show a differential hormonal regulation of GH and PRL receptor gene expression in the pancreatic islets, which may play a role in the adaptive beta-cell growth during pregnancy.
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PMID:Effects of sex and pregnancy hormones on growth hormone and prolactin receptor gene expression in insulin-producing cells. 836 59

The alpha 1E voltage-dependent calcium channel has not been clearly identified with a specific neuronal calcium current. To help identify the role of alpha 1E, we examined differential expression of alpha 1E splice variants in mouse brain and cultured cell lines and examined the gene structure of the region encoding the amino terminal. Three splice variants were analyzed by a ribonuclease protection assay, and a fourth variant reported previously in a fetal human alpha 1E sequence was also detected in mouse brain and a pituitary cell line. Whole brain, telencephalon, and olfactory bulb contained predominantly the splice variant corresponding to alpha 1E-1 although other known variants could be detected. Neuroendocrine cells in vitro (beta TC3 insulinoma cells and AtT-20 pituitary cell lines) expressed predominantly one alpha 1E isoform. The existence of a 5' exon accounting for the origin of variant 5' ends reported in different species was suggested by the sequence of the mouse alpha 1E gene in the region encoding the amino terminal.
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PMID:Isoform expression of the voltage-dependent calcium channel alpha 1E. 906 72