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)

The effect of epinephrine on amino acid (AA) metabolism was examined in 33 healthy volunteers who participated in four studies. Nine subjects participated in study I, which consisted of four parts: euglycemic insulin clamp, insulin plus epinephrine, insulin plus epinephrine plus propranolol, and insulin plus propranolol. In study II six subjects received epinephrine with hepatic-femoral venous catheterization. In study III five individuals received epinephrine with somatostatin plus basal insulin replacement. In study IV quadriceps muscle biopsy was performed in six subjects after epinephrine or insulin infusion. Both epinephrine and insulin caused a generalized decline in all plasma AA except alanine. With combined epinephrine-insulin infusion, the decrease in plasma AA was additive. Propranolol blocked the hypoaminoacidemic effect of epinephrine but failed to alter the AA lowering action of insulin. Epinephrine, while maintaining basal insulinemia, reduced the catechol's hypoaminoacidemic effect by 39%. After epinephrine, splanchnic alanine uptake increased, but plasma alanine remained constant because of a parallel rise in muscle alanine production. Plasma/intracellular concentrations of branched-chain amino acids (BCAA) and all gluconeogenic amino acids, except alanine, decreased after both epinephrine and insulin. In summary, the effect of epinephrine on plasma/intracellular total, gluconeogenic, and BCAA concentrations is similar to insulin.
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PMID:Regulation of amino acid metabolism by epinephrine. 197 Jul 11

The characteristics of somatostatin (SRIF) receptors in rat pancreatic beta-cells were investigated using rat islets and the beta-cell line HIT-T15 (HIT). The biochemical properties of the SRIF receptors were examined with 125I-labeled des-Ala-1,Gly-2-desamino-Cys-3-[Tyr-11]- dicarba3,14-somatostatin (CGP 23996). 125I-CGP 23996 bound to SRIF receptors in HIT cells with high affinity and in a saturable manner. The binding of 125I-CGP 23996 to SRIF receptors was blocked by SRIF analogues with a rank order of potency of somatostatin 28 (SRIF-28) greater than D-Trp-8-somatostatin greater than somatostatin 14 (SRIF-14). To investigate the physical properties of the HIT cell SRIF receptor, the receptor was covalently labeled with 125I-CGP 23996 using photo-cross-linking techniques. 125I-CGP 23996 specifically labeled a protein of 55 kDa in HIT cell membranes. The size of the SRIF receptor in HIT cells is similar to the size of the SRIF receptor labeled with 125I-CGP 23996 in membranes of freshly isolated islets, suggesting that the physical properties of SRIF receptors in HIT cells and rat islet cells are similar. The binding studies suggest that beta-cells predominantly express a SRIF-28-preferring receptor. In freshly isolated islets, glucose- and arginine-stimulated insulin release was effectively blocked by SRIF-28 but not by SRIF-14. SRIF-14 did inhibit arginine-stimulated glucagon secretion from freshly isolated islets. The dissociation of the inhibitory effects of SRIF-28 and SRIF-14 on insulin and glucagon release from freshly isolated islets suggests that the two peptides act through different receptors in islets to regulate hormone secretion.
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PMID:Pancreatic beta-cell somatostatin receptors. 197 86

The holocephalan fishes were the first class of vertebrate in evolution to develop a pancreatic gland with both endocrine and exocrine parenchyma. An extract of the pancreas of one such fish, the Pacific ratfish (Hydrolagus colliei) contained somatostatin-like immunoreactivity (141 pmol/g wet wt), measured with an antiserum raised against mammalian somatostatin-14. Automated Edman degradation and fast atom bombardment-mass spectrometry established the primary structure of the major molecular form as Ala-Gly-Cys-Lys-Ser-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys. A minor component of somatostatin-like immunoreactivity, constituting 8% of the total, was of approximate molecular weight 6000. Thus, in the ratfish pancreas prosomatostatin-I is processed predominantly to somatostatin-14, as in the mammalian pancreas, but the resulting tetradecapeptide contains the substitution Ser for Asn at position 5.
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PMID:[Ser5]-somatostatin-14: isolation from the pancreas of a holocephalan fish, the Pacific ratfish (Hydrolagus colliei). 198 69

We have investigated the effects of serum from patients with motor neurone disease (MND) and of the plant-derived excitotoxin beta-N-methylamino-L-alanine (L-BMAA) on thyrotrophin-releasing hormone (TRH) and somatostatin (SS) production by fetal rat brainstem cell cultures. Compared to age- and sex-matched normal and neurological disease control sera, MND sera produce a 2- to 3-fold increase in TRH content of the cultures with no change in SS levels. L-BMAA produced similar dose-related and stereospecific effects on the cultures increasing TRH levels to 2-fold with no effect on SS levels. These findings may be relevant to the understanding of the aetiology of MND.
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PMID:Motor neurone disease serum and beta-N-methylamino-L-alanine stimulate thyrotrophin-releasing hormone production by cultured brain cells. 198 41

GH-releasing peptide (His-DTrp-Ala-Trp-DPhe-Lys-NH2 or GHRP) releases GH by a unique and complementary dual site of action on the hypothalamus and pituitary. These effects are mediated via non-GH-releasing hormone (non-GHRH) and nonopiate receptors in rats. Select types of opiates are known to release GH by a hypothalamic site of action, and thus, the dermorphin heptapeptide and benzomorphan opiate agonist 2549 used in this study presumably act on the hypothalamus to release GH. Neither dermorphin nor 2549 released GH or augmented the GH responses of GHRP or GHRH in vitro by a direct pituitary action, while GHRH antiserum inhibited the GH response of both dermorphin and 2549 in vivo. Evidence indicates that these opiates and GHRP administered together synergistically release GH, demonstrating the independent action(s) of GHRP and the opiates. Present data indicate that one of the major differences in the actions of dermorphin, 2549, and GHRP is the inhibition of somatostatin (SRIF) release by the opiates but not by GHRP. Although the actions of dermorphin, 2549, and GHRP on GH release are GHRH dependent, release of endogenous GHRH does not explain how GH is released synergistically by the combination of these peptides. It is proposed that dermorphin/2549 synergistically release GH with GHRP or GHRH because these opiates inhibit SRIF release. Since the GHRP plus GHRH synergistic GH release was not explained by inhibition of SRIF or stimulation of GHRH, an alternative mechanism is proposed to explain how GHRP synergistically release GH in combination with GHRH. The complementary, rather dramatic synergistic interaction of GHRP, GHRH, and dermorphin or GHRP, GHRH, and 2549 in releasing GH again strongly supports the independent actions of these compounds.
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PMID:On the actions of the growth hormone-releasing hexapeptide, GHRP. 200 15

1. The purpose of the present study was to maintain physiological plasma non-esterified fatty acid levels and to (i) examine their effect on skeletal muscle insulin-stimulated glucose uptake and metabolite exchange using the forearm technique, and (ii) evaluate their effect on whole-body glucose uptake and fuel oxidation. 2. Intralipid (10%) and heparin (Lipid) or saline (Control) was administered to eight healthy male subjects on separate occasions for 210 min. Insulin, glucagon and somatostatin were administered from 60 to 210 min in each study and euglycaemia was maintained. 3. Plasma non-esterified fatty acid levels plateaued at 420 +/- 50 mumol/l with the Lipid infusion but were completely suppressed during the Control clamp. Forearm non-esterified fatty acid uptake increased with the Lipid infusion (+50 +/- 10 nmol min-1 100 ml-1 of forearm) and was accompanied by a significant decrease in forearm glucose uptake (+3.23 +/- 0.25 versus +3.65 +/- 0.35 mumol min-1 100 ml-1 of forearm, Lipid and Control, respectively; P less than 0.05) and alanine release (-84 +/- 12 versus -113 +/- 15 nmol min-1 100 ml-1 of forearm, Lipid and Control, respectively; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Physiological levels of plasma non-esterified fatty acids impair forearm glucose uptake in normal man. 216 6

The aim of this study was to determine if glucagon can stimulate hepatic glucose production in prolonged fasted (7 days) animals. Two protocols were used; in one ("hormone replacement"; n = 4), intraportal basal replacement amounts of insulin and glucagon were given during a somatostatin infusion, whereas, in the other ("glucagon excess"; n = 5) basal insulin was given along with somatostatin and excess glucagon. Plasma insulin levels were similar and constant throughout both protocols (6 +/- 1 microU/ml). The plasma glucagon was basal in the hormone-replacement protocol (49 +/- 9 pg/ml) but rose from 46 +/- 7 to 448 +/- 35 pg/ml (P less than 0.05) in the other protocol. Plasma glucose levels and the rates of glucose production were unchanged during hormone replacement but rose from 100 +/- 5 to 199 +/- 28 mg/dl and from 1.5 +/- 0.1 to a peak of 5.6 +/- 0.2 mg.kg-1.min-1 at 15 min (P less than 0.05) and an eventual plateau of 2.7 +/- 0.2 mg.kg-1.min-1 (P less than 0.05) in response to glucagon excess. Because of the sluggish increase in gluconeogenic parameters, the early marked rise in glucose production was attributable to increased glycogenolysis. Eventually, however, the gluconeogenic rate rose, with net hepatic uptake of alanine increasing 50% and fractional alanine extraction doubling. Gluconeogenic efficiency and conversion increased in response to glucagon excess by 0.30 +/- 0.05 and 159 +/- 48%, respectively, although it should be noted that these parameters rose 0.15 +/- 0.06 and 150 +/- 49% in the hormone-replacement protocol. In conclusion, even after a prolonged fast physiological glucagon can cause hyperglycemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of hyperglucagonemia on hepatic glycogenolysis and gluconeogenesis after a prolonged fast. 218 65

The relative importance of insulin and glucagon as primary regulators of glucose metabolism in vivo was assessed in 18-hour fasted conscious dogs. Glucose turnover was determined using [3-3H]glucose and gluconeogenesis was assessed using tracer ([14C]alanine) and A-V difference techniques during a 40-minute control period and a 3-hour period during which various hormonal perturbations were brought about. During the infusion of somatostatin and basal intraportal replacement amounts of insulin and glucagon for the entire study, the plasma glucose concentration (109 +/- 5 mg/dL), glucose production (3.24 +/- 0.30 mg/kg/min), and glucose utilization (3.17 +/- 0.32 mg/kg/min) remained unchanged. When the glucagon infusion rate was increased fourfold at the end of the control period, the plasma glucose level increased from 107 +/- 4 to 225 +/- 23 mg/dL by 1 hour and remained elevated. Glucose production increased from 3.14 +/- 0.29 to 7.66 +/- 0.51 mg/kg/min by 15 minutes and decreased to 4.23 +/- 0.35 mg/kg/min by 3 hours. Glucose utilization rose from a basal value of 3.20 +/- 0.26 to 5.46 +/- 0.27 mg/kg/min by 3 hours. When a fourfold increase in the insulin infusion rate was brought about at the end of the control period, glucose production decreased from 2.83 +/- 0.20 to 1.16 +/- 0.57 mg/kg/min by 1 hour, after which it increased slightly (1.62 +/- 0.81 mg/kg/min). Glucose utilization increased from 2.92 +/- 0.30 to 8.12 +/- 1.12 mg/kg/min by 3 hours. Euglycemia was maintained by glucose infusion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of insulin on glucagon-stimulated glucose production in the conscious dog. 224 75

The effects on pancreatic responses of highly potent cyclic hexapeptide (cyclo (N-Me-Ala-Phe-D-Trp-Lys-Thr-Phe)) (Veber analog) and octapeptide analogs of somatostatin such as D-Phe-Cys-Phe-D-Trp-Lys-Thr-Cys-Thr-ol (SMS 201-995), D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2 (RC-121), and D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Trp-NH2 (RC-160) have been compared with somatostatin tetradecapeptide (SS-14) and atropine. The parameters evaluated were pancreatic responses to secretin and meat feeding in conscious dogs with chronic pancreatic fistula and amylase release from the dispersed pancreatic acini. The analogs were administered intravenously or intraduodenally. The cyclic hexapeptide and octapeptide analogs, given iv in graded doses against a constant background stimulation with secretin, produced similar and dose-dependent inhibition of pancreatic HCO3- and protein secretion. Analogs RC-121, RC-160, and the Veber analog were about two to four times more active than SS-14 in suppressing HCO3- secretion and equipotent in reducing protein secretion, but SMS 201-995 was only about half as potent as somatostatin in inhibiting HCO3-. RC-160 was effective in inhibiting secretin-induced protein secretion at lower doses than other analogs. In tests with feeding, SMS 201-995, the Veber analog, RC-121, and RC-160 were more potent inhibitors of exocrine pancreatic secretion of HCO3- and protein and exhibited more prolonged inhibitory effects than SS-14. The Veber analog, RC-121, and RC-160 were also more effective after intraduodenal administration. Atropine also caused significant inhibition of both HCO3- and protein responses to secretin and meal feeding. All four analogs decreased the postprandial insulin and pancreatic polypeptide release to a similar degree as SS-14. Neither SS-14 nor the analogs tested significantly affected basal or caerulein-, gastrin-, secretin-, or bethanechol-stimulated amylase release from the dispersed canine pancreatic acini. Atropine reduced amylase release induced by bethanechol, but not that stimulated by caerulein, gastrin, or secretin. This indicated that the analogs, as somatostatin, are ineffective as secretory inhibitors in vitro. We conclude that cyclic hexapeptide and octapeptide analogs are more potent and longer acting inhibitors of pancreatic secretion than somatostatin-14 in vivo.
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PMID:Comparison of somatostatin and its highly potent hexa- and octapeptide analogs on exocrine and endocrine pancreatic secretion. 244 2

The aim of this study was to investigate the role of thyroid hormones and glucocorticoids on GH secretion. Secretion of GH in response to GH-releasing hormone (GHRH) (5 micrograms/kg) was markedly (P less than 0.001) decreased in hypothyroid rats in vivo (peak GH responses to GHRH, 635 +/- 88 micrograms/l in euthyroid rats vs 46 +/- 15 micrograms/l in hypothyroid rats). Following treatment with tri-iodothyronine (T3; 20 micrograms/day s.c. daily for 2 weeks) or cortisol (100 micrograms/day s.c. for 2 weeks) or T3 plus cortisol, a marked (P less than 0.01) increase in GH responses to GHRH was observed in hypothyroid rats (peak GH responses, 326 +/- 29 micrograms/l after T3 vs 133 +/- 19 micrograms/l after cortisol vs 283 +/- 35 micrograms/l after cortisol plus T3). In contrast, none of these treatments modified GH responses to GHRH in euthyroid animals. Hypothyroidism was also associated with impaired GH responses to the GH secretagogue, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6). Secretion of GH in response to GHRP-6 in vivo was reduced (P less than 0.01) in hypothyroid rats (peak GH responses, 508 +/- 177 micrograms/l in euthyroid rats vs 203 +/- 15 micrograms/l in hypothyroid rats). In-vitro studies carried out using monolayer cultures of rat anterior pituitary cells derived from euthyroid and hypothyroid rats showed a marked impairment of somatotroph responsiveness to both GHRP-6 and somatostatin in cultures derived from hypothyroid rats. In summary, our data suggest that thyroid hormones and glucocorticoids influence GH secretion by modulating somatotroph responsiveness to different GH secretagogues.
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PMID:Effects of hypothyroidism, tri-iodothyronine and glucocorticoids on growth hormone responses to growth hormone-releasing hormone and His-D-Trp-Ala-Trp-D-Phe-Lys-NH2. 249 23


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