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)

AMP-activated protein kinase (AMPK) plays a key role in regulating metabolism, serving as a metabolic master switch. The aim of this study was to assess whether increased concentrations of the AMP analog, 5-aminoimidazole-4-carboxamide-1-beta-D-ribosyl-5-monophosphate, in the liver would create a metabolic response consistent with an increase in whole-body metabolic need. Dogs had sampling (artery, portal vein, hepatic vein) and infusion (vena cava, portal vein) catheters and flow probes (hepatic artery, portal vein) implanted >16 days before a study. Protocols consisted of equilibration (-130 to -30 min), basal (-30 to 0 min), and hyperinsulinemic-euglycemic or -hypoglycemic clamp periods (0-150 min). At t = 0 min, somatostatin was infused and glucagon was replaced in the portal vein at basal rates. An intraportal hyperinsulinemic (2 mU . kg(-1) . min(-1)) infusion was also initiated at this time. Glucose was clamped at hypoglycemic or euglycemic levels in the presence (H-AIC, n = 6; E-AIC, n = 6) or absence (H-SAL, n = 6; E-SAL, n = 6) of a portal venous 5-aminoimidazole-4-carboxamide-ribofuranoside (AICAR) infusion (1 mg . kg(-1) . min(-1)) initiated at t = 60 min. In the presence of intraportal saline, glucose was infused into the vena cava to match glucose levels seen with intraportal AICAR. Glucagon remained fixed at basal levels, whereas insulin rose similarly in all groups. Glucose fell to 50 +/- 2 mg/dl by t = 60 min in hypoglycemic groups and remained at 105 +/- 3 mg/dl in euglycemic groups. Endogenous glucose production (R(a)) was similarly suppressed among groups in the presence of euglycemia or hypoglycemia before t = 60 min and remained suppressed in the H-SAL and E-SAL groups. However, intraportal AICAR infusion stimulated R(a) to increase by 2.5 +/- 1.0 and 3.4 +/- 0.4 mg . kg(-1) . min(-1) in the E-AIC and H-AIC groups, respectively. Arteriovenous measurement of net hepatic glucose output showed similar results. AICAR stimulated hepatic glycogen to decrease by 5 +/- 3 and 19 +/- 5 mg/g tissue (P < 0.05) in the presence of euglycemia and hypoglycemia, respectively. AICAR significantly increased net hepatic lactate output in the presence of hypoglycemia. Thus, intraportal AICAR infusion caused marked stimulation of both hepatic glucose output and net hepatic glycogenolysis, even in the presence of high levels of physiological insulin. This stimulation of glucose output by AICAR was equally marked in the presence of both euglycemia and hypoglycemia. However, hypoglycemia amplified the net hepatic glycogenolytic response to AICAR by approximately fourfold.
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PMID:Portal venous 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside infusion overcomes hyperinsulinemic suppression of endogenous glucose output. 1567 95

Skeletal muscle protein synthesis is elevated in neonates in part due to an enhanced response to the rise in insulin and amino acids after eating. In vitro studies suggest that glucose plays a role in protein synthesis regulation. To determine whether glucose, independently of insulin and amino acids, is involved in the postprandial rise in skeletal muscle protein synthesis, pancreatic-substrate clamps were performed in neonatal pigs. Insulin secretion was inhibited with somatostatin and insulin was infused to reproduce fasting or fed levels, while glucose and amino acids were clamped at fasting or fed levels. Fractional protein synthesis rates and translational control mechanisms were examined. Raising glucose alone increased protein synthesis in fast-twitch glycolytic muscles but not in other tissues. The response in muscle was associated with increased phosphorylation of protein kinase B (PKB) and enhanced formation of the active eIF4E.eIF4G complex but no change in phosphorylation of AMP-activated protein kinase (AMPK), tuberous sclerosis complex 2 (TSC2), mammalian target of rapamycin (mTOR), 4E-binding protein-1 (4E-BP1), ribosomal protein S6 kinase (S6K1), or eukaryotic elongation factor 2 (eEF2). Raising glucose, insulin, and amino acids increased protein synthesis in most tissues. The response in muscle was associated with phosphorylation of PKB, mTOR, S6K1, and 4E-BP1 and enhanced eIF4E.eIF4G formation. The results suggest that the postprandial rise in glucose, independently of insulin and amino acids, stimulates protein synthesis in neonates, and this response is specific to fast-twitch glycolytic muscle and occurs by AMPK- and mTOR-independent pathways.
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PMID:Glucose stimulates protein synthesis in skeletal muscle of neonatal pigs through an AMPK- and mTOR-independent process. 1755 Oct 2

AMP-activated protein kinase (AMPK), an enzyme functioning as a cellular sensor of low energy, stores and promotes adaptive changes in growth, differentiation, and metabolism. While AMPK is primarily thought of as a regulator of systemic metabolism, it has been clearly established that it also has a role in the regulation of cell growth and may be a therapeutic target for proliferative disorders. Growth hormone (GH) secretion from the anterior pituitary and GH-induced synthesis and release of insulin-like-growth-factor-1 (IGF-1) from the liver determine linear growth before puberty. Actually, GH and IGF-1 are potent growth factors affecting cell growth and differentiation in different tissues, and still have anabolic functions and serve as essential regulators of fuel metabolism in adulthood, as well. A variety of peripheral hormonal and metabolic signals regulate GH secretion either by acting directly on the anterior pituitary and/or modulating GH-releasing hormone or somatostatin release from the hypothalamus. Actually, intracellular transduction of endocrine and metabolic signals regulating somatotroph function is still debated. Based on the previously summarized contents, the aim of the present work has been to review currently available data suggesting a role of AMPK in the interplay between GH axis activity and metabolic functions.
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PMID:Points of integration between the intracellular energy sensor AMP-activated protein kinase (AMPK) activity and the somatotroph axis function. 2273 9

We investigated the effects of the AMPK activator AICAR as compared to somatostatin-14 on cell viability and GH secretion in human GH-secreting pituitary adenomas in vitro and in rat GH3 cells. Overnight treatment with AICAR increased phospho-(threonine-172) AMPK levels (activated AMPK) in cultured human adenomas. As to the effects on cell viability, four adenomas out of 15 were responsive to AICAR (0.4mM) and five adenomas were responsive to SS-14 (100 nM). One adenoma was responsive to both somatostatin and AICAR. The effects of cotreatment with SS-14 and AICAR were investigated in eight adenomas. In two adenomas, the effects of AICAR+SS-14 did not exceed the effect of AICAR. In two adenomas which were not responsive to either AICAR or SS-14, the cotreatment was able to reduce cell viability versus control. Two adenomas were not responsive to any treatment. As to the effects on GH secretion, nine adenomas out of 15 were responsive to AICAR. Twelve adenomas were responsive to SS-14. Eight adenomas were responsive to both AICAR and SS-14. Cotreatment exceeded the effect of single treatments in 4 out of 10 adenomas. In GH3 cells, AICAR reduced the activity of p70S6 kinase, which plays an important role in cell growth. SS-14 did not affect significantly AMPK phosphorylation and p70S6K activity but it was able to enhance the inhibitory effect of AICAR on phospho-S6 levels. Moreover, AICAR and SS-14 reduced ERK phosphorylation with a different time course. The combined treatment reduced phospho-ERK levels at any time point.
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PMID:Effects of AMPK activation and combined treatment with AMPK activators and somatostatin on hormone secretion and cell growth in cultured GH-secreting pituitary tumor cells. 2311 72

Metformin (MET) has recently emerged as a potentially active agent in cancer prevention and treatment. MET is thought to exert its antitumor effects either via modification of systemic metabolism or through cell-autonomous effects (e.g., activation of AMPK and inhibition of the mTOR pathway). Preliminary findings of the PRIME-NET study suggest that the addition of MET to treatment with everolimus (EVE) and/or somatostatin analogs (SSAs) can provide clinical benefit in diabetic neuroendocrine tumor (NET) patients. In light of this and other retrospective evidence of MET's anticancer activity in NETs, prospective studies are needed. A pilot, single-arm, open-label, prospective study (MetNET-2 trial, NCT02823691) was designed to evaluate the safety of MET in combination with lanreotide in well-differentiated gastrointestinal (WD GI) and lung NETs.
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PMID:Rationale and protocol of MetNET-2 trial: Lanreotide Autogel plus metformin in advanced gastrointestinal or lung neuroendocrine tumors. 2858 Jul 93