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: UNIPROT:P61278 (somatostatin)
22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin receptors from rabbit retinal membranes were solubilized in an active form using a mixture of the detergent n-octyl b-D-glucopyranoside (OG) and CHAPS. The binding of [125I]-Try11-somatostatin to the soluble extract was saturable and of high affinity, with an apparent affinity constant (Kd) of 0.60 +/- 0.20 nM and a maximum number of binding sites (Bmax) of 80 +/- 48 fmol/mg protein. The specific binding of [125I]Tyr11-somatostatin was inhibited in a dose-dependent manner only by the somatostatinergic analogs. The biochemical characteristics of both the membrane-bound and soluble receptors were studied by photoaffinity labeling techniques. Analysis by SDS-PAGE and subsequent autoradiography revealed the presence of a major protein of similar relative molecular mass (M(r) 54,000 and 57,000 for membrane and soluble sites, respectively). The photolabeling of this protein was specifically inhibited by somatostatin-28, somatostatin-14, SMS 201-995 (a synthetic octapeptide analog of somatostatin) but not by bombesin and somatostatin-28(1-14). The non-hydrolysable GTP analog guanosine-5'-O-(3-thio-triphosphate) (GTP gamma S) regulated the photolabeling of [125I]Tyr11-somatostatin to the membrane and soluble receptors. These studies describe for the first time the successful solubilization of the somatostatin receptor and the biochemical characterization of both membrane-bound and soluble receptors from rabbit retina.
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PMID:Solubilization of active somatostatin receptors from rabbit retina. 849 40

Functionally active cultures of human pituitary adenoma cells producing excessive amounts of the growth hormone (somatotropinomas), of prolactin (prolactinomas) or of the both hormones (mixed type adenomas) have been prepared and their secreted molecular forms studied. SDS-PAAG electrophoresis combined with immunoblotting making use of poly- and monoclonal antibodies revealed that the growth hormone and prolactin are secreted by adenoma cells in several molecular forms typical of normal human pituitary. The major form secreted by the growth hormone is 22K; the minor forms are 20K (the product of alternative splicing of pre-mRNA) and the split-off two-chain form 25K. The major form secreted by prolactin is 23K; the minor form is glycosylated 25K. No significant differences in the ratios of molecular forms of the hormones were found either under basal conditions of culturing or under the influence of the pituitary function regulators, somatostatin and thyroliberin. At the same time, the data obtained suggest that pituitary adenoma cells can secrete some amount of "abnormal" molecular forms of the hormones, e.g., immature products of postribosomal processing or large-sized immunoreactive fragments. Hence, pituitary adenoma cell cultures are an effective tool in biochemical and physiological studies of molecular forms of the human growth hormone and prolactin and of their secretion.
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PMID:[Molecular forms of human growth hormone and prolactin, secreted by cultured pituitary tumor cells]. 855 61

The effects of somatostatin (SRIF) on prolactin (PRL) synthesis and release were examined in primary cultured pituitary cells derived from normal and estradiol (E2)-primed male rat pituitaries. The cells were continuously incubated in a pulse medium containing [3H]leucine with or without 10(-6) mol/l SRIF for a period of 15, 30, 60, 180 or 360 min. Following incubation, the medium was recovered and the cells were fractionated into cytosolic and granular fractions. PRL was isolated by SDS-PAGE and newly synthesized PRL ([3H]PRL) was identified by coincident peaks of tritium activities and PRL contents. The specific activity (SA, c.p.m./ng), a ratio of [3H]PRL to total PRL, was determined for the granular, cytosolic and medium fractions. In control and SRIF-treated groups of non-primed pituitary cells, SAs of all three fractions significantly increased during the 6-h incubation. Cytosolic and granular SAs showed similar profiles of increasing rate in comparison to control. Medium SAs showed a significantly higher value in the SRIF-treated group than in the control group only at 180 min. These observations indicate that, in the non-primed condition, PRL synthesis is not inhibited by SRIF. Medium SAs in the E2-primed group were significantly higher than SAs in the non-primed control cells during the initial 3 h of incubation, and cytosolic and granular SAs were significantly higher than those of the non-primed control during the 3- to 6-h incubation period. These observations demonstrate that E2 enhances PRL synthesis and secretion of newly synthesized PRL. SRIF treatment of E2-primed lactotrophs resulted in a significant decrease in SAs of all three fractions as compared with those of the E2-primed control. Our results indicate that in normal male rat pituitary cells SRIF does not inhibit PRL synthesis but effectively inhibits PRL synthesis in E2-primed lactotrophs. This suggests that the inhibitory action of SRIF on PRL synthesis is estrogen dependent.
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PMID:Somatostatin does not inhibit prolactin synthesis in normal male rat pituitary cells but inhibits prolactin synthesis in estradiol-primed pituitary cells. 856 73

The reliability of provocative stimuli of GH secretion in the diagnosis of GH deficiency is still controversial. Until now, normative values of GH response to various stimuli have not been established properly. In 472 children and adolescents with normal stature (n = 295, height SDS range -1.5 to 1.2) or normal short stature (n = 177, height SDS range -3.7 to -1.8), we studied the GH response to physical exercise, insulin-induced hypoglycemia, arginine (ARG), clonidine, levodopa, glucagon, pyridostigmine (PD), GHRH, PD + GHRH, and ARG + GHRH. The peak GH responses (range) to various stimuli were: 1) physical exercise: 3.0-28.3 micrograms/L; 2) insulin-induced hypoglycemia: 2.7-46.4 micrograms/L; 3) ARG: 0.5-48.4 micrograms/L; 4) clonidine: 3.8-86.0 micrograms/L; 5) levodopa: 1.9-40.0 micrograms/L; 6) glucagon: 1.9-49.5 micrograms/L; 7) PD: 2.5-35.0 micrograms/L; 8) GHRH: 2.7-102.7 micrograms/L; 9)PD + GHRH: 19.6-106.0 micrograms/L; and 10) ARG + GHRH: 19.4-120.0 micrograms/L. Our results show that all conventional stimuli of GH secretion frequently failed to increase GH levels, showing values lower than that arbitrarily assumed, so far, as minimum normal GH peak, i.e. 7 or 10 micrograms/L. When combined with PD or ARG (substances inhibiting hypothalamic somatostatin release), GHRH becomes the most powerful test to explore the secretory capacity of somatotrope cells (the GH response being always higher than 19 micrograms/L). Therefore, only GHRH combined with PD or ARG may be able to clearly differentiate normal children from patients with GH deficiency, though a normal GH response to these tests cannot rule out the existence of GH hyposecretory state because of hypothalamic dysfunction.
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PMID:Reliability of provocative tests to assess growth hormone secretory status. Study in 472 normally growing children. 878 91

The role of somatostatin (SS-14) in the regulation of rat liver regeneration was examined by using thymidine incorporation into hepatocyte DNA labeled with tritiated thymidine, a nuclear-labeling index, and the binding of 125I-tyr11-SS-14 to hepatocytes isolated at various times after partial hepatectomy. The data demonstrated no suppressive effect of SS-14 on insulin and glucagon-stimulated thymidine incorporation into hepatocyte DNA as early as 2 h after partial hepatectomy. These data were substantiated by a nuclear labeling index studies. At 2 h, 125I-tyr11-SS-14 binding to its specific sites on isolated hepatocytes was undetectable. There was a time-dependent increase in binding of 125I-tyr11-SS-14 to hepatocytes obtained at various times after partial hepatectomy. There was a significant decrease in the number of binding sites after partial hepatectomy as determined by Scatchard analysis. The data were supported by autoradiography analysis of affinity labeled 125I-tyr11-SS-14-binding protein complex followed by SDS-PAGE. SS-14 also inhibited intracellular cAMP in hepatocytes obtained at 18 h after hepatectomy. The data are consistent with the hypothesis that SS-14 participates via its own receptor in the regulation of the liver regeneration.
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PMID:Preferential suppression of insulin-stimulated proliferation of cultured hepatocytes by somatostatin: evidence for receptor-mediated growth regulation. 890 19

It has been speculated that opiate tolerance and dependence may occur at the level of gene expression. Our previous studies have shown that the binding activity of a nuclear factor (ssCRE-BP) to single-stranded CRE of somatostatin gene is altered by long-term treatment with morphine in the mouse cerebellum. ssCRE-BP was purified from the mouse cerebellum by a combination of chromatography on DNA affinity agarose and Mono Q HR. The native protein exhibited a molecular size of 110-150 kDa by gel filtration, and two polypeptides of about 35-40 kDa were observed on SDS-PAGE. The cloning and sequencing of a cDNA encoding ssCRE-BP showed that the protein possesses a glycine-rich domain and a glutamine-rich domain in the amino terminus and the carboxyl terminus, respectively. To investigate the function of ssCRE-BP in the brain, recombinant glutathione-S-transferase (GST) fusion proteins containing ssCRE-BP were expressed in bacterial systems. Rabbit anti-ssCRE-BP antibodies were raised against a GST-ssCRE-BP fusion protein. Using the antibodies in western blot analysis, a polypeptide of approximately 66 kDa was detected in the brain. These findings indicate that ssCRE-BP is involved in opiate tolerance and dependence.
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PMID:Characterization of single-stranded cAMP response element binding protein (ssCRE-BP) from mouse cerebellum. 895 22

Due to persistent qualitative abnormalities in GH secretion following treatment, and lack of a sensitive marker of GHD in mid-adult life it is extremely difficult to diagnose GHD in treated acromegalic patients. The diagnosis of GHD in patients with pituitary disease relies on provocative tests of GH reserve. Arginine releases GH by reducing somatostatin inhibition of GH release, whereas GH secretagogues (GHS) affect GH release by direct stimulation of the GHS receptor, though an intact GH releasing hormone (GHRH) axis is a prerequisite. The peak GH response to insulin-induced hypoglycaemia and arginine in acromegalic patients, in whom basal serum GH levels of less than 5 mU/l have been achieved, is greatly diminished in those treated by hypothalamo-pituitary irradiation. We aimed to study the response of successfully treated acromegalic patients to the growth hormone secretagogue hexarelin in view of its different putative mechanism of action, and in addition, to determine whether it has any value in the diagnosis of GH deficiency in this subset of patients. Nineteen acromegalic patients, in whom mean serum GH levels below 5 mU/l have been achieved through treatment, were recruited. Eight of the patients had been treated by surgery alone (Group A) and 11 had received primary or postoperative irradiation (Group B). All patients underwent 20 min blood sampling to provide a 24-h GH profile. Serum IGF-I was measured from a sample drawn between 0900 h and 1000 h. On a second visit arginine 20 g/m2 was infused over 30 min, blood samples were taken before commencing the infusion and at 30-min intervals thereafter for 180 min. At the final visit hexarelin 1.5 mcg/kg was administered as an intravenous bolus at t = 0. Blood was drawn at 15-min intervals from - 30 to 180 min. All patients in group A showed an increment in serum GH following hexarelin (DeltaGHHEX) > 20 mU/l, a normal response to arginine, and a mean 24-h GH > 0.5 mU/l. In group B only 4/11 achieved a DeltaGHHEX > 20 mU/l, 5/11 producing a response of < 2 mU/l. Four of the five patients with a DeltaGHHEX < 2 mU/l were also demonstrated to have a mean 24-h GH of < 0.5 mU/l and serum IGF-I SDS < + 0.5. All four patients in Group B who achieved a DeltaGHHEX > 20 mU/l, were observed to show an absent or minimal GH response to arginine. Despite loss of the GH response to arginine, the DeltaGHHEX is retained in a proportion of those patients in whom "safe" GH levels were achieved following irradiation. From the putative mechanisms of action of these provocative agents a plausible explanation would be that the GHRH axis is more resilient than endogenous somatostatin-secreting neurones to radiation-induced damage. Furthermore, GH secretagogues may have a role, in combination with serum IGF-I levels, in the diagnosis of GH deficiency in treated acromegaly.
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PMID:The diagnosis of growth hormone deficiency (GHD) in successfully treated acromegalic patients. 1116 24

To construct the ss/HBsAg protein gene-engineering vaccine for developing the diagnosis and cure tumors in clinical medicine and promoting the growth in animal husbandry production. A pair of primers were designed according separately to the sequence of Somatostatin gene(S14) and HBsAg gene. Their gene fragments were separately amplified by using PCR and cloned, following sequencing, the DNA fragments were inserted into pBluescript vector. Then the ss/HBsAg chimera was constructed and was cloned into pPICZaA plasmid, and transformed into electroporated Pichia pastoris. High yield protein expression was obtained. Expressed protein was proved with high specificity and it's molecular weigh was about 28 KD identified by SDS-PAGE and Western blot.
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PMID:[Construction and expression of somatostatin (S14) and hepatitis B surface antigen gene in yeast Pichia pastoris]. 1255 29

Urotensin II (U-II) is a disulfide-bridged undecapeptide recently identified as the ligand of an orphan G-protein-coupled receptor. Human U-II (H-Glu-Thr-Pro-Asp-cyclo[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH) has been described as the most potent vasoconstrictor compound identified to date. With the aim of elucidating the active conformation of hU-II, we have performed a spectroscopic analysis of hU-II minimal active fragment hU-II(4-11) in different environmental conditions. The analysis indicated that hU-II(4-11) was highly structured in the anisotropic membrane mimetic SDS solution, showing a type II' beta-turn structure, which is almost unprecedented for L-amino acid peptides. Micelle bound structure of hU-II(4-11) was then compared with those of four synthetic analogues recently synthesized in our lab, bearing modified Cys residues at position 5 and/or position 10 and characterized by different levels of agonist activity. The structures of the active compounds were found to be very similar to that of hU-II(4-11), while a barely active compound does not show any propensity to beta-turn formation. Furthermore, distances among putative pharmacophoric points in the structures of the active compounds obtained in SDS solution are in good agreement with those found in a recently described non-peptide agonist of the hU-II receptor. A type II' beta-turn structure was already found for the somatostatin analogue octreotide. On the basis of the similarity of the primary and 3D structures of U-II and somatostatin analogues and on the basis of the sequence homology between the GPR14/UT-II receptor and members of the somatostatin receptor family, a common evolutionary pathway for the signal transmission system activated by these peptide can be hypothesized.
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PMID:Unraveling the active conformation of urotensin II. 1502 56

GHRH stimulates GH secretion in chickens as in mammals. However, nothing is known about the chicken GHRH receptor (GHRH-R). Here we report the cDNA sequence of chicken GHRH-R. Comparison of the cDNA sequence with the chicken genome localized the GHRH-R gene to chicken chromosome 2 and indicated that the chicken GHRH-R gene consists of 13 exons. Expression of all exons was confirmed by RT-PCR amplification of pituitary mRNA. The amino acid sequence predicted by the GHRH-R cDNA is homologous to that in other vertebrates and contains seven transmembrane domains and a conserved hormone-binding domain. The predicted size of the GHRH-R protein (48.9 kDa) was confirmed by binding of (125)I-GHRH to chicken pituitary membranes and SDS-PAGE. GHRH-R mRNA was readily detected by RT-PCR in the pituitary but not in the hypothalamus, total brain, lung, adrenal, ovary, or pineal gland. Effects of corticosterone (CORT), GHRH, ghrelin, pituitary adenylate cyclase-activating peptide, somatostatin (SRIF), and TRH on GHRH-R and GH gene expression were determined in cultures of chicken anterior pituitary cells. GHRH-R and GH mRNA levels were determined by quantitative real-time RT-PCR. Whereas all treatments affected levels of GH mRNA, only CORT, GHRH, and SRIF significantly altered GHRH-R mRNA levels. GHRH-R gene expression was modestly increased by GHRH and suppressed by SRIF at 4 h, and CORT dramatically decreased levels of GHRH-R mRNA at 72 h. We conclude that adrenal glucocorticoids may substantially impact pituitary GH responses to GHRH in the chicken through modulation of GHRH-R gene expression.
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PMID:Identification of the chicken growth hormone-releasing hormone receptor (GHRH-R) mRNA and gene: regulation of anterior pituitary GHRH-R mRNA levels by homologous and heterologous hormones. 1646


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