Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.27.5 (RNase)
17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations within the growth hormone receptor (GHR) gene that lead to an inactivated or truncated GHR protein cause abnormal growth and small adult size in a variety of species (Laron dwarfism). We studied a line of miniature Bos indicus cattle that have phenotypic (small mature size) and endocrine (increased blood growth hormone and decreased blood insulin-like growth factor-I concentrations) similarities to Laron dwarfs. Liver mRNA from miniature and control cattle was used to amplify a cDNA within the coding region of the GHR. The miniature cattle had GHR mRNA size (determined by Northern blot) and cDNA sequence that were similar to control cattle and, therefore, were unlike most Laron dwarf genotypes in which the GHR gene is mutated. Amounts of mRNA from liver as well as muscle (superficial neck and longissimus) were analyzed by ribonuclease protection assay for IGF-I, total GHR, GHR 1A (inducible, liver-specific GHR mRNA), and GHR 1B (constitutive GHR mRNA). Four control and five miniature bulls were tested. As expected, liver IGF-I mRNA was decreased in the miniature cattle (approximately 12% of control; P < 0.01). The amount of the total GHR as well as GHR 1A mRNA were also decreased in liver (17% and 19% of control, respectively; P < 0.01). Other GHR mRNA, including GHR 1B mRNA, were similar for miniature and control cattle. In muscle, there was a tendency (P < 0.10) for decreased IGF-I mRNA and increased GHR mRNA in miniature compared with control cattle. In summary, a novel phenotype for Laron dwarfism in Bos indicus cattle was associated with underexpression of GHR 1A mRNA, but not other GHR mRNA variants in liver. In addition to decreased GHR 1A mRNA, the miniature cattle had decreased liver IGF-I mRNA. Full expression of GHR 1A in liver, therefore, may be required for full liver IGF-I expression and normal growth.
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PMID:A novel phenotype for Lardon dwarfism in miniature Bos indicus cattle suggests that the expression of growth hormone receptor 1A in liver is required for normal growth. 1062 32

In order to examine the hormonal regulation of the prolactin-receptor (PRL-R) gene expression during mammary gland development, ewes were treated to induce lactation via an estrogen-progesterone-hydrocortisone and ovine growth hormone treatment. In situ hybridization analysis was used and revealed that sex steroids increased PRL-R mRNA levels in the mammary gland. Using RNase protection assay we showed that the estradiol + progesterone treatment increased both the levels of the long and the short forms of PRL-R mRNA. Addition of hydrocortisone increased the level of alphaS1-casein transcripts and the level of the ratio of the long to the short form of the PRL-R mRNA. This ratio can be further enhanced by addition of ovine growth hormone to the latter treatment. This suggests a role of hydrocortisone and ovine growth hormone in the alternative splicing that leads to the preferential expression of the long form of the PRL-R mRNA. In conclusion, the present experiments suggest that estrogen, progesterone and hydrocortisone are the major regulators of the PRL-R gene expression during pregnancy and prepare the mammary gland for its differentiation.
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PMID:Increase in prolactin receptor (PRL-R) mRNA level in the mammary gland after hormonal induction of lactation in virgin ewes. 1070 63

The extent to which the local somatotrophic axis is functional in extrahepatic tissues in the neonate is unclear. We therefore determined the expression of growth hormone (GH) receptor (GHR), and insulin-like growth factors I and II (IGF-I and IGF-II) mRNA in liver and skeletal muscle (longissimus) of neonatal pigs given daily intramuscular injections of either recombinant porcine GH (1 mg/kg body wt; n = 6) or saline (n = 5) for 7 days. Exogenous GH increased plasma concentrations of GH 30-fold and IGF-I threefold. Abundances of specific mRNA in liver and muscle were measured by RNase protection assays (values are arbitrary density units). In liver, GH treatment increased GHR (6.0 vs. 9.7; P < 0.01) and IGF-I (5.2 vs. 49.0; P < 0.001) but not IGF-II (19.5 vs. 17.2) mRNA. In muscle, GH treatment increased IGF-I mRNA (13.3 vs. 22.8; P < 0.05) but not GHR (8.3 vs. 9.5) or IGF-II (16.1 vs. 16.9). These results demonstrate that exogenous GH can induce local somatotrophic function predominantly in liver but also in muscle of newborn pigs. Our novel finding on the selective increase in muscle IGF-I but not GHR gene expression suggests differences in posttranscriptional regulation and/or intracellular signaling mechanisms.
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PMID:Exogenous growth hormone induces somatotrophic gene expression in neonatal liver and skeletal muscle. 1074 70

A growing body of information now supports the existence of a complete intraovarian insulin-like growth factor I (IGF-I) system. Although the precise role of IGF-I in the context of ovarian physiology remains to be determined, it is likely that IGF-I may engage in the amplification of gonadotrophin hormonal action. These facts and experiments with animals establishing the ovaries of multiple species as a site of growth hormone (GH) reception and action have led to the use of recombinant GH (rGH) as an adjunctive agent to potentiate ovulation induction by exogenous gonadotrophins. Whether intraovarian IGF-I plays an intermediary role in GH hormonal action at the ovarian level remains uncertain at present. The aim of this study was to evaluate whether rGH administration to pre-menopausal women could modify the expression of the IGF-I gene in the ovary. The expression of the IGF-I gene was examined in a time-dependent manner in normal pre-menopausal ovaries obtained from nine women treated with rGH and nine control women treated with placebo, using solution hybridization/RNase protection assays. Ovarian tissue samples were obtained 24 h (six women) and 7 days (12 women) following rGH/placebo injection. Total RNA (20 microg) from whole pre-menopausal ovaries (with or without rGH treatment) as well as from human granulosa cells was hybridized with a human IGF-I antisense RNA. IGF-I peptide, but not oestradiol, serum concentrations increased significantly 24 h after rGH injection. IGF-I gene, however, was not expressed in the luteinized granulosa cells and whole pre-menopausal ovaries irrespectively of rGH treatment in ovarian samples analysed both 1 and 7 days following rGH injection. On the contrary, IGF-II mRNA transcribed from the fetal or fetal-neonatal IGF-II promoter and IGF-I receptor mRNA (both used as hybridization control) were both found in whole pre-menopausal ovary and luteinized granulosa cells. Nevertheless, no changes in the hybridization patterns were seen in the absence or presence of rGH. These studies demonstrate that rGH administration to normal premenopausal women does not change the expression of insulin-like growth factors and their receptor genes in the pre-menopausal human ovary. Furthermore, these results provide further evidence against locally produced IGF-I as responsible for any ovarian effects seen in systemic rGH administration.
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PMID:Growth hormone does not increase the expression of insulin-like growth factors and their receptor genes in the pre-menopausal human ovary. 1083 48

Growth hormone-secretagogue receptor (GHSR) RNA is known to be expressed in the hypothalamus and pituitary. Since endogenous GH secretagogue (GHS) is still unknown, the physiological role of GHS and GHSR in growth is not well understood. In this study, we have determined the effects of growth hormone in GH-releasing hormone receptor (GHRHR) and GHSR RNA expression in spontaneous Dwarf rats (SDRs) which are deficient in GH secretion, with or without GH replacement. Twenty-five-day-old SDRs received daily s.c. injection of human GH (40 microg/kg BW x 2/day) or control solution for two weeks. On day 40, the rats were sacrificed by decapitation and the pituitaries were immediately removed and quickly frozen. Total RNA was extracted from the pituitary, and mRNA coding GHSR was detected and semi-quantitated by competitive RT-PCR. Pituitaries from control SDRs showed strong GHSR RNA expression and the expression level was 5 to 10 times higher in females than in males. When GH was replaced, GHSR RNA expression greatly decreased. Pituitary GHRHR RNA expression, determined by RNase Protection Assay, was similar in male and female control animals; and was also greatly reduced in rats treated with GH when compared to the control. These results suggest that the expression of both GHSR and GHRHR is regulated by growth hormone, presumably via changes in hypothalamic GHRH and/or endogenous GHS. The apparent sexual dimorphism in GHSR indicates different regulatory effects of sex steroid in young growing SDRs.
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PMID:Regulation of pituitary growth hormone-secretagogue and growth hormone-releasing hormone receptor RNA expression in young Dwarf rats. 1089 Jan 84

This study demonstrates the cloning and in-vitro characterisation of the marmoset monkey (Callithrix jacchus) prolactin receptor cDNA. The marmoset prolactin receptor cDNA was generated by reverse transcription-polymerase chain reaction using adrenal RNA and primers designed from prolactin receptor conserved regions. Sequence analysis predicts a mature protein of 598 amino acids exclusive of the 24 amino acid signal peptide. The marmoset prolactin receptor cDNA shares 93 and 61% base pair, and 89 and 61% amino acid sequence homologies with the long form human and rat prolactin receptor cDNA, respectively. The marmoset prolactin receptor cDNA sequence retains all the receptor sequences that have been shown previously to be essential for ligand binding, structural integrity and signal transduction. Transfection of human 293 fibroblast cells with the marmoset prolactin receptor cDNA (three independent experiments) confirmed the expression of a receptor that has high binding affinity to human growth hormone (K(a)=3.6+/-0.07 nM(-1) and B(max)=7.55+/-2.06x10(-11) M) and human prolactin (K(a)=3.1+/-0.12 nM(-1) and B(max)=2.87+/-0.66x10(-11) M). Functionality of the receptor was assessed by co-transfection of 293 fibroblast cells with marmoset prolactin receptor cDNA and the Jak2 cDNA, or marmoset prolactin receptor and a Stat5 responsive element linked to the luciferase coding sequence. Incubation of the cells with 18 nM ovine prolactin resulted in rapid phosphorylation of Jak2 as ascertained by Western blotting. In addition, the marmoset prolactin receptor cDNA led to 9.06+/-0.47-fold induction of luciferase gene activity. This was comparable with the induction observed following transfection with the human prolactin receptor cDNA (8.55+/-0. 5-fold). In-vivo prolactin receptor expression in the marmoset monkey was assessed by ribonuclease protection assay and detected in a number of tissues including female reproductive organs. These data confirm the cloning and functionality of the marmoset prolactin receptor cDNA. The marmoset prolactin receptor shares a high sequence homology with the long-form human prolactin receptor, and both receptors bind hormones with comparable affinity and confer a similar intracellular response. The marmoset monkey may provide a useful tool to investigate the role of prolactin in primate reproduction.
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PMID:Sequence and functional characterisation of the marmoset monkey (Callithrix jacchus) prolactin receptor: comparative homology with the human long-form prolactin receptor. 1100 May 23

The hypothesis that growth hormone (GH) can affect immune responses in man has been evaluated by monitoring cytokine expression in cultures from peripheral blood mononuclear cells, by enzyme-linked immunosorbent assay (ELISA) and ribonuclease protection assay, and in tonsillar cells by ELISA. In addition to pituitary GH (GH-N), the placental form (GH-V), differing from pituitary GH by 13 amino acids has also been tested. Only few effects reached statistical significance and were in no case greater than 15%. Pituitary GH slightly reduced IL-5 production and stimulated IFN-gamma production. The latter effect was also observed with prolactin and could thus be induced through the prolactin receptor. It is proposed that GH has no strong effects on the parameters investigated, possibly as a result of redundancy in the cytokine network. Alternatively, effects on leukocytes are mediated by other tissues such as the liver or are clear only in response to stronger challenges.
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PMID:Limited effects of placental and pituitary growth hormone on cytokine expression in vitro. 1102 31

In this study we describe the development of a RNA:RNA solution hybridization-RNase protection assay to quantify STAT5 mRNA in total RNA extracts from rat tissues. The assay is sensitive and reproducible. We quantified STAT5 mRNA levels in liver and thymus lymphocytes from male and female control rats and from rats treated with a single dose of recombinant human growth hormone (rhGH). No significant sex differences in the expression pattern were observed in both studied tissues, but STAT5 mRNA levels were significantly (P< 0.05) higher in liver than in thymus lymphocytes. STAT5 mRNA levels were significantly (P< 0.05) increased by a pulse of GH given to either male or female normal rats, suggesting a regulation of STAT5 gene expression in the studied tissues. In conclusion, quantitative solution hybridization-RNase protection assay of STAT5 mRNA provides a tool to further advance the study of the regulatory mechanisms involved in STAT5 gene expression.
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PMID:Comparison of STAT5 mRNA levels in GH-treated male and female rats analysed by a solution hybridization assay. 1104 19

The MtT/S somatotroph cell line should be a growth hormone-releasing hormone (GHRH)-responsive model system for the study of physiological control of growth hormone (GH) transcription because GH secretion from these cells is stimulated by GHRH. To examine the GH transcriptional activity of these cells, endogenous GH mRNA levels were measured using a ribonuclease protection assay following treatment under a variety of hormonal conditions. While omission of serum led to reduction of GH mRNA to 22% of control levels by 2 days and to 8% by 5 days (P<0.05 for both), GH mRNA levels were maintained at control values in serum-free medium containing 5 nM dexamethasone and 30 pM triiodothyronine (TDM). However, the addition of 10 nM GHRH under any treatment condition did not significantly alter GH mRNA levels. Characterization of the MtT/S cells showed that GHRH-receptor (GHRH-R) mRNA was detectable by reverse transcription-polymerase chain reaction (RT-PCR) amplification. Measurement of extracellular cAMP showed that the MtT/S cells have basal levels of > or =20 nmol/10(6) cells per h in both serum-containing and serum-free media, and that GHRH had no effect on cAMP levels, suggesting constitutive activation. To rule out the possibility of autocrine stimulation by GHRH produced endogenously, GHRH mRNA was not detectable in MtT/S cells using RT-PCR amplification. The stimulatory G-protein alpha subunit, mutations of which are known to activate adenylate cyclase constitutively in acromegaly, was sequenced but found not to differ from normal pituitary in the regions most commonly mutated. Finally, treatment with 10 microM forskolin, to directly activate adenylate cyclase, increased GH mRNA to 140% of controls in TDM, and to 163% in serum-free medium after 2 days, and to 166% in TDM-treated cells and 174% in serum-free culture after 5 days (all P<0.05). Taken together, these data indicate that although MtT/S cells express the GHRH-R, GHRH cannot stimulate adenylate cyclase to increase GH transcription due to constitutive elevation of cAMP levels, by a means that may be similar to that in cases of acromegaly not caused by oncogenic gsp mutations.
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PMID:GH mRNA levels are elevated by forskolin but not GH releasing hormone in GHRH receptor-expressing MtT/S somatotroph cell line. 1116 46

The growth hormone (GH) receptor gene is characterized by heterogeneity in the 5'-untranslated region (UTR). The technique of 5'-rapid amplification of cDNA ends (RACE) was employed to identify potentially novel 5'-UTRs for the GH receptor gene. One of the RACE clones displayed sequence homology to the human V5-UTR; hence this transcript was designated as L5. Sequence analysis of genomic DNA established that L5 was immediately upstream of exon 2. Northern blot analysis indicated that two bands of sizes congruent with4.8 kb, corresponding to GH receptor mRNA, and congruent with1.5 kb corresponding to GH binding protein mRNA, were detectable in liver, skeletal muscle, kidney and heart but not in brain, spleen, lung or testis. Fluorescent 5'-nuclease real-time RT-PCR based analysis indicated that in the placenta and fetal liver, the L5 transcript represented 10-15% of the GH receptor transcripts. In the adult liver, heart and kidney, the L5 transcript is less abundant accounting for 1-5% of the total GH receptor transcripts. Primer extension and ribonuclease protection assays were performed to identify the major transcription start site at 778 bp from the ATG codon. Transient transfection experiments revealed that the 5'-flanking sequence had promoter activity in rat placental trophoblast (HRP.1), Chinese hamster ovary (CHO) and mouse liver (BNL CL.2) cells. Analysis of expression of the L5 transcript in the non-obese diabetic (NOD) mouse, a model of spontaneous autoimmune diabetes, indicated that the expression of the L5 transcript was decreased in liver and kidney by 80-90 and 40-50%, respectively, but expression remained unchanged in the heart.
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PMID:Identification and characterization of a novel transcript of the murine growth hormone receptor gene exhibiting development- and tissue-specific expression. 1116 47


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