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Targeting Adrenergic Receptors in Metabolic Therapies for Heart Failure. Int J Mol Sci 2021; 22:ijms22115783. [PMID: 34071350 PMCID: PMC8198887 DOI: 10.3390/ijms22115783] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
The heart has a reduced capacity to generate sufficient energy when failing, resulting in an energy-starved condition with diminished functions. Studies have identified numerous changes in metabolic pathways in the failing heart that result in reduced oxidation of both glucose and fatty acid substrates, defects in mitochondrial functions and oxidative phosphorylation, and inefficient substrate utilization for the ATP that is produced. Recent early-phase clinical studies indicate that inhibitors of fatty acid oxidation and antioxidants that target the mitochondria may improve heart function during failure by increasing compensatory glucose oxidation. Adrenergic receptors (α1 and β) are a key sympathetic nervous system regulator that controls cardiac function. β-AR blockers are an established treatment for heart failure and α1A-AR agonists have potential therapeutic benefit. Besides regulating inotropy and chronotropy, α1- and β-adrenergic receptors also regulate metabolic functions in the heart that underlie many cardiac benefits. This review will highlight recent studies that describe how adrenergic receptor-mediated metabolic pathways may be able to restore cardiac energetics to non-failing levels that may offer promising therapeutic strategies.
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Perez DM. Current Developments on the Role of α 1-Adrenergic Receptors in Cognition, Cardioprotection, and Metabolism. Front Cell Dev Biol 2021; 9:652152. [PMID: 34113612 PMCID: PMC8185284 DOI: 10.3389/fcell.2021.652152] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/29/2021] [Indexed: 12/13/2022] Open
Abstract
The α1-adrenergic receptors (ARs) are G-protein coupled receptors that bind the endogenous catecholamines, norepinephrine, and epinephrine. They play a key role in the regulation of the sympathetic nervous system along with β and α2-AR family members. While all of the adrenergic receptors bind with similar affinity to the catecholamines, they can regulate different physiologies and pathophysiologies in the body because they couple to different G-proteins and signal transduction pathways, commonly in opposition to one another. While α1-AR subtypes (α1A, α1B, α1C) have long been known to be primary regulators of vascular smooth muscle contraction, blood pressure, and cardiac hypertrophy, their role in neurotransmission, improving cognition, protecting the heart during ischemia and failure, and regulating whole body and organ metabolism are not well known and are more recent developments. These advancements have been made possible through the development of transgenic and knockout mouse models and more selective ligands to advance their research. Here, we will review the recent literature to provide new insights into these physiological functions and possible use as a therapeutic target.
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Affiliation(s)
- Dianne M Perez
- The Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, United States
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Miyamoto Y, Miyamoto M. Immunohistochemical localizations of secretin, cholecystokinin, and somatostatin in the rat small intestine after acute cisplatin treatment. Exp Mol Pathol 2004; 77:238-45. [PMID: 15507242 DOI: 10.1016/j.yexmp.2004.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Indexed: 10/26/2022]
Abstract
Cisplatin (CDDP) is an antitumor platinum complex that causes the well-studied side effect of renal tubular failure. In the present study, the acute effects of CDDP treatment on the localization of gut hormones in the rat small intestine were examined by immunohistochemistry. Male Sprague-Dawley rats were used for these experiments. Rats were injected intravenously with CDDP (3 mg/kg) in saline or were left untreated (control). After the rats were euthanized at 1, 3, 5, or 10 days after CDDP treatment, the small intestines (duodenum, jejunum, and ileum) were quickly removed, fixed, embedded in paraffin, and cut. No mucosal toxicity was detected by histopathological observation in any of the intestines of CDDP-treated rats. The immunohistochemical detection was performed using anti-secretin, anti-cholecystokinin (CCK), and anti-somatostatin with the avidin-biotin-immuno-peroxidase procedure. The total number of immunoreactive cells per complete cross-section was counted. In the duodenum, the numbers of secretin-immunoreactive cells and somatostatin-immunoreactive cells were dramatically increased 5 days after CDDP treatment. In the jejunum, the number of CCK-immunoreactive cells was increased 1 day after CDDP treatment and those of secretin-immunoreactive cells and CCK-immunoreactive cells were increased 5 days after CDDP treatment. In the ileum, the number of CCK-immunoreactive cells was increased 1 day after CDDP treatment. The change in the secretin-immunoreactive cell count may be caused by metabolic inhibition of gastrin following CDDP-induced nephrotoxicity. The change in the CCK-immunoreactive cell count may promote the excretion of bile. Therefore, somatostatin may regulate secretin and CCK secretion. We conclude that the distribution of these hormone-immunoreactive cells in the rat small intestine might be controlled by CDDP-induced nephrotoxicity without gut mucosal toxicity.
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Affiliation(s)
- Yohei Miyamoto
- Toxicology Laboratory, Pharmaceutical Research Laboratories, Toray Industries, Inc., Kamakura, Kanagawa 248-8555, Japan.
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Kopecky M, Semecky V, Trejtnar F, Laznicek M, Laznickova A, Nachtigal P, Decristoforo C, Mather SJ, Mäcke HR. Analysis of accumulation of 99mTc-octreotide and 99mTc-EDDA/HYNIC-Tyr3-octreotide in the rat kidneys. Nucl Med Biol 2004; 31:231-9. [PMID: 15013489 DOI: 10.1016/j.nucmedbio.2003.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2002] [Revised: 01/31/2003] [Accepted: 06/26/2003] [Indexed: 11/17/2022]
Abstract
The aim of this study was to compare renal handling and distribution of (99m)Tc-octreotide and (99m)Tc-EDDA/HYNIC-Tyr(3)-octreotide (HYNIC-TOC) in rats. In kidney perfusion experiments, the renal clearance value of (99m)Tc-octreotide was three times lower than that of (99m)Tc-EDDA/HYNIC-TOC. The predominant renal excretion of (99m)Tc-EDDA/HYNIC-TOC was associated with a high and long-term renal accumulation up to 48 hrs. Microautoradiographic results indicated that (99m)Tc-EDDA/HYNIC-TOC was retained mainly in the renal medulla within the cells of the collecting ducts and in the surrounding tissue. Lower positivity was found in the proximal and distal tubular cells. We conclude that the mechanism of renal accumulation of somatostatin analogues renal accumulation is complex and that proximal tubular reabsorption is probably not the main mechanism for uptake of (99m)Tc-EDDA/HYNIC-TOC in the kidneys. The presence of the somatostatin receptors, differences in the tonicity level within kidneys and other possible mechanisms could participate in their renal accumulation.
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Affiliation(s)
- Martin Kopecky
- Department of Biological and Medical Sciences, Charles University, Faculty of Pharmacy, Heyrovskeho 1203, 50005 Hradec Kralove, Czech Republic.
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Sheridan MA, Kittilson JD. The role of somatostatins in the regulation of metabolism in fish. Comp Biochem Physiol B Biochem Mol Biol 2004; 138:323-30. [PMID: 15325331 DOI: 10.1016/j.cbpc.2004.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Revised: 04/20/2004] [Accepted: 04/23/2004] [Indexed: 10/26/2022]
Abstract
Somatostatins (SS) are a structurally and functionally diverse family of peptide hormones. Somatostatins possess a wide variety of biological functions, including numerous secretotropic, developmental, and metabolic effects. Studies on fish have revealed considerable insight into the role of SS on the regulation of intermediary metabolism. Somatostatins promote both lipid and carbohydrate breakdown in fish and lamprey. Such actions are mediated by secretotropic effects of SS. For example, SS inhibit insulin (INS); insulin deficiency favors lipolysis and glycogenolysis over lipogenesis and glycogenesis. Somatostatins also directly stimulate the breakdown of stored triacylglycerols (TG) and glycogen in storage tissues. In addition, SS interact with the growth and reproductive axes of fish, findings that suggest SS serve to modulate energy partitioning among various growth, development and reproductive processes.
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Affiliation(s)
- Mark A Sheridan
- Department of Biological Sciences, North Dakota State University, Science, Fargo, ND 58105, USA.
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Turman MA, Apple CA. Human proximal tubular epithelial cells express somatostatin: regulation by growth factors and cAMP. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:F1095-101. [PMID: 9841501 DOI: 10.1152/ajprenal.1998.274.6.f1095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Somatostatin modulates several renal tubular cell functions, including gluconeogenesis and proliferation. In this study, we demonstrate that cultured human proximal tubular epithelial cells (PTEC) express somatostatin. We also demonstrate positive and negative regulation of PTEC somatostatin production. We found that PTEC derived from 14 different human donors consistently expressed somatostatin mRNA and/or peptide as detected by RT-PCR and enzyme-linked immunoassay. Furthermore, Northern blot analysis revealed that PTEC express the same size mRNA transcript (750 nucleotides) as human thyroid carcinoma (TT) cells. The PTEC mitogens, epidermal growth factor(EGF) and hydrocortisone, inhibit PTEC somatostatin secretion, whereas forskolin (a direct stimulator of adenylate cyclase) and fetal bovine serum stimulate secretion. These findings raise the possibility that renal-derived somatostatin modulates tubular cell function in an autocrine/paracrine manner. Manipulation of this pathway may lead to novel methods with which to alter tubular cell proliferation and function in vivo.
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Affiliation(s)
- M A Turman
- Department of Pediatrics, Ohio State University, Columbus, Ohio 43205, USA
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Atrens DM, Menéndez JA. Somatostatin and the paraventricular hypothalamus: modulation of energy balance. Brain Res 1993; 630:238-44. [PMID: 7906997 DOI: 10.1016/0006-8993(93)90662-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of somatostatin injections (0.1, 1 and 5 micrograms) into the paraventricular nucleus of the hypothalamus (PVN) were investigated in an open-circuit calorimeter. Wistar rats were tested, with no food available during the tests. The 0.1 and 1 microgram doses produced large and long-lasting decreases in respiratory quotient, which indicates the preferential utilization of fats as an energy substrate. The 5 micrograms dose produced a brief decrease in energy expenditure. Locomotor activity was not affected by any treatment which indicates that the effects on respiratory quotient and energy expenditure are not secondary to changes in activity. These findings demonstrate that somatostatin in the PVN inhibits thermogenesis and induces the preferential utilization of fats while sparing carbohydrate reserves. However, it is significant that the effects on energy expenditure and energy substrate utilisation occurred at different doses. These data constitute the first evidence that somatostatin in the PVN produces a primary modulation of the metabolic parameters central to energy balance. In separate experiments, all three doses of somatostatin increased blood glucose concentration over a one hour period, and the 5 micrograms dose decreased body weight over a 24 h period. Food and water intake were not affected by the somatostatin injections. Taken together, these findings are interpreted in a model in which somatostatin is a signal to the PVN of increased body fat. This mobilizes sympathetic mechanisms which increase fat utilization and blood glucose levels.
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Affiliation(s)
- D M Atrens
- Department of Psychology, University of Sydney, NSW, Australia
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Kusterer K, Blöchle C, Konrad T, Palitzsch KD, Usadel KH. Rat liver injury induced by hypoxic ischemia and reperfusion: protective action by somatostatin and two derivatives. REGULATORY PEPTIDES 1993; 44:251-6. [PMID: 8097890 DOI: 10.1016/0167-0115(93)90134-t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Natural somatostatin and two synthetic derivatives (octreotide, 008) were tested for their ability to prevent hypoxic ischemic cell injury of the isolated perfused rat liver. The cyclic octapeptide octreotide is known to have endocrine and cytoprotective activities, whereas the cyclic hexapeptide 008 exerts protective actions without any endocrine effects. In isolated perfused rat livers flow rate was reduced and oxygen supply interrupted for 180 min. Then the livers were normoxically reperfused for 30 min. LDH and GLDH activity as well as Ca2+ concentration was determined in the effluent. Hypoxic ischemia led to a substantial enzyme release from the liver and to a strong Ca2+ influx. Pretreatment with somatostatin, octreotide and 008 significantly reduced LDH and GLDH release (P < 0.001). The somatostatins significantly increased the Ca(2+)-influx into the hypoxic, ischemic perfused rat liver (P < 0.001). Ca(2+)-influx is known to be an essential factor in the final common pathway of cell death induced by hypoxic ischemia. Even though the administration of the somatostatins was associated with an enhanced Ca(2+)-influx, the somatostatins reduced hypoxic ischemic liver injury.
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Affiliation(s)
- K Kusterer
- Center of Internal Medicine, University of Frankfurt, Frankfurt am Main, Germany
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García-Escribano C, Díez-Marqués ML, González-Rubio M, Rodríguez-Puyol M, Rodríguez-Puyol D. Somatostatin antagonizes angiotensin II effects on mesangial cell contraction and glomerular filtration. Kidney Int 1993; 43:324-33. [PMID: 8095076 DOI: 10.1038/ki.1993.50] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of somatostatin (ST) on the regulation of the glomerular filtration rate have not been extensively studied. The present experiments were designed to analyze this possible relationship. ST alone did not modify the planar cell surface area (PCSA) of cultured rat mesangial cells (CRMC), but it prevented and reversed the reduction in PCSA induced by 10 nM angiotensin II (Ang II) in a dose- and time-dependent manner. ST (1 microM) completely prevented and reversed the increase in the myosin light chain phosphorylation induced by 10 nM Ang II. Incubation with pertussis toxin (PT, 0.5 micrograms/ml) inhibited the effect of ST on the Ang II-dependent changes in PCSA, but this effect was not inhibited by the blockade of the vasodilatory prostaglandins (indomethacin, 10 microM) or nitric oxide (L-N-methyl-arginine, 0.2 mM) synthesis. 2',5'-dideoxyadenosine (DDA, 0.1 mM), an adenylate cyclase blocker, and methylene blue (MB, 30 microM), a soluble guanylate cyclase blocker, did not interfere with the ST inhibitory effect on the Ang II-dependent reduction in PCSA of rat mesangial cells. ST also blocked the reduction in PCSA induced by phorbol myristate acetate (PMA, 300 nM). ST was also able to prevent and revert the Ang II dependent reduction in glomerular cross-sectional area of isolated rat glomeruli, also in a dose- and time-dependent fashion. Finally, intravenous administration of ST (200 ng/kg body wt as a bolus plus a continuous injection of 25 ng/min/kg body wt) partially blocked the reduction in GFR (measured as CIn) and RPF (measured as CPAH) and the increase in filtration fraction induced by the intravenous administration of Ang II (1.7 micrograms/min/kg body wt) in anesthetized rats. In summary, these results suggest that ST could antagonize the renal actions of Ang II, increasing the GFR and RPF decreased by Ang II, and this effect could be dependent, at least partially, on a direct relaxing effect of ST on mesangial cells.
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Affiliation(s)
- C García-Escribano
- Department of Physiology, University of Alcalá de Henares, Madrid, Spain
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Rosa J, Rosa J, Fister V. Effects of somatostatin on glucagon-stimulated glycogenolysis and gluconeogenesis in hepatocytes cultured in vitro. ACTA ACUST UNITED AC 1992; 146:205-11. [PMID: 1359734 DOI: 10.1111/j.1748-1716.1992.tb09409.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effects of somatostatin (SS-14) on glycogenolysis and gluconeogenesis in rat hepatocytes cultured in vitro in a serum-free medium were investigated. Somatostatin (122 nmol l-1) did not significantly change the basal glucose production with or without pyruvate (10 mmol l-1). Glucagon strongly (over 100%) increased the glucose production in hepatocytes incubated in a medium supplemented with 10 mmol l-1 pyruvate. This increase in glucose production is the result of increased rates of gluconeogenesis and glycogenolysis. Somatostatin partially inhibited the glucagon stimulated increase in glucose production. Glucagon also significantly increased the glucose production in a glucose-free medium without pyruvate, which resulted from an increase of glycogenolysis. Somatostatin did not inhibit the increase in glucose production in these conditions. After a 4 h 'fast', glycogen in hepatocytes fell to a very low level. Glucose production was minimal. After the addition of pyruvate, there was a increase in gluconeogenesis and glucose production. Glucagon stimulated the rate of gluconeogenesis. Somatostatin completely inhibited this glucagon-stimulated increase in gluconeogenesis.
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Affiliation(s)
- J Rosa
- Department of Physiology, Zagreb University School of Medicine, Croatia
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Abstract
Previous investigations of centrally administered somatostatin (SRIF) have tended to employ pharmacological (nmol and greater) doses of the peptide. Under this protocol contradictory findings of feeding effects have been reported. There is evidence that the use of physiological doses can induce a completely distinct response from that obtained with pharmacological doses. In order to discern whether physiological doses of centrally administered somatostatin have any effect on feeding. SRIF in doses ranging from 0.4 pmol to 3 nmol were administered into the lateral ventricles of rats. Low pmol doses (0.4-40) administered during the light photoperiod increased 1 h feeding whereas 3 nmol decreased 1 h feeding. None of the doses tested during the dark photoperiod significantly altered 1 h food intake. Similarly, no significant change in 24-h food intake was observed following injections of any of the doses tested, whether in the light or dark. A dose of SRIF that increased feeding (1 pmol) did not significantly alter 1 h water intake when applied centrally in the light nor did it alter spontaneous locomotor activity. Furthermore, when applied peripherally it did not change 1 h food intake. These studies suggest that SRIF may work centrally to regulate food intake. A similarity exists between SRIF's feeding effects and the feeding effects we have previously described following central injections of growth hormone-releasing factor (GRF), both in terms of dose-response and photosensitivity. This suggests that these 2 peptides may act via a common mechanism to regulate food consumption; possibly in co-ordination with their regulation of growth hormone release. The possibility that such feeding regulation occurs as part of a short intrahypothalamic feedback loop is discussed.
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Affiliation(s)
- R J Unwin
- Department of Clinical Pharmacology, Royal Postgraduate Medical School, Hammersmith Hospital, London, England
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Fairweather I, Mahendrasingam S, Johnston CF, Halton DW, Shaw C. Peptidergic nerve elements in three developmental stages of the tetraphyllidean tapeworm Trilocularia acanthiaevulgaris. An immunocytochemical study. Parasitol Res 1990; 76:497-508. [PMID: 1696377 DOI: 10.1007/bf00931055] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The localization and distribution of seven neuropeptides in the nervous system of the plerocercoid, adult and free proglottis stages of the tetraphyllidean tapeworm Trilocularia acanthiaevulgaris have been determined by an indirect immunofluorescence technique. Six of the peptides are vertebrate-derived, namely, pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), substance P (SP) and somatostatin (SRIF); the seventh is the invertebrate neuropeptide, FMR Famide. This is the first demonstration of VIP and SP immunoreactivity in a cestode parasite, and for SRIF this is its first description in any parasitic platyhelminth. Cell bodies and nerve fibres immunoreactive to PP, PYY, VIP, SP and FMRFamide are present throughout the CNS; the distributions of PHI and SRIF were more restricted. In the PNS, nerve fibres immunoreactive to PP occur in the bothridia, whilst in the free proglottis nerve fibres immunoreactive to PYY and VIP innervate the gonads; VIP-immunoreactive nerve elements also supply the reproductive ducts. Extra-neuronal sitings of peptide immunoreactivities were evident for PHI, in association with the excretory system, and for SRIF, in presumed tegumental cell bodies in the free proglottis. The results are discussed in relation to the possible roles of the peptides in the neurophysiology and developmental biology of the worm.
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Affiliation(s)
- I Fairweather
- Department of Biology, Queen's University, Belfast, Northern Ireland
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Eriksson LS, Wahren J. Intravenous and subcutaneous administration of a long-acting somatostatin analogue: effects on glucose metabolism and splanchnic haemodynamics in healthy subjects. Eur J Clin Invest 1989; 19:213-9. [PMID: 2499481 DOI: 10.1111/j.1365-2362.1989.tb00220.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of SMS 201-995, a long-acting somatostatin analogue, on splanchnic blood flow and glucose metabolism, was investigated in five groups of healthy subjects. Groups A (n = 4), B (n = 5), C (n = 5) and D (n = 5) were studied before, during and after a 60-min intravenous infusion of SMS (1.7, 0.8, 0.2 and 0.1 micrograms min-1, respectively). Group E (n = 6) was investigated before and for 6 h after a subcutaneous injection of 25 micrograms of SMS. The splanchnic blood flow decreased by 20-25% in all groups in response to SMS and remained low during the entire observation periods. Arterial concentrations of glucose showed a 15-20% decline during SMS infusion in Groups A and B (P less than 0.05-0.01) and a less pronounced decrease in the other groups. Fifteen minutes after the end of infusion the glucose levels started to rise and in group A, the levels were significantly higher than basal (+25%, P less than 0.05-0.01) at 90-180 min after the end of infusion. The net splanchnic glucose production, determined in groups A and B, decreased by 65-75% in response to SMS infusion. Towards the end and immediately after the infusions, however, the net glucose output increased, but decreased again at 30-60 min after the end of infusion. Arterial, insulin and glucagon concentrations decreased significantly during infusion in all groups. This decline was more pronounced for insulin (50%) than for glucagon (20-25%) and insulin concentrations remained low for a longer period after the end of infusions.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L S Eriksson
- Department of Medicine, Karolinska Institute, Huddinge Hospital, Stockholm, Sweden
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Priestley T, Woodruff GN. The inhibitory effect of somatostatin peptides on the rat anococcygeus muscle in vitro. Br J Pharmacol 1988; 94:87-96. [PMID: 2900039 PMCID: PMC1853932 DOI: 10.1111/j.1476-5381.1988.tb11502.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
1. Electrically evoked contractions of the rat anococcygeus muscle were inhibited in a concentration-dependent manner by somatostatin-14 (SS14), -28 (SS28) and two synthetic hexapeptide analogues: L-363,301 (Pro-Phe-D-Trp-Lys-Thr-Phe) and L-363,586 (N-Me-Ala-Tyr-D-Trp-Lys-Val-Phe), with pIC50 values of 7.41, 7.38, 7.07 and 8.34, respectively. 2. The inhibitory effects of SS14 were dependent on stimulation frequency and external calcium ion concentration. Calcium behaved as a non-competitive antagonist of SS14, it reduced the maximal inhibitory effect of the peptide and at a concentration of 5.08 mM it significantly affected the pIC50 value. 3. SS14 (3 x 10(-7) M) did not affect the tonic actions of bath-applied noradrenaline in the absence of field stimulation. 4. The effects of SS14 persisted in naloxone (10(-5) M) and were, therefore, not due to an action at opiate receptors. Furthermore, experiments involving the lyophilization of bath contents, showed no evidence to support an indirect mechanism involving the release of an endogenous inhibitory substance. 5. High concentrations (10(-5) M) of SS14 or L-363,301 inhibited the relaxation response evoked by electrical stimulation of guanethidine (3 x 10(-4) M)-treated preparations. 6. These results are consistent with similar actions of SS14 on other smooth muscle preparations and are presumed to reflect a presynaptic inhibition of transmitter release by a direct action on somatostatin receptors. The antagonistic effect of calcium on this response is discussed with reference to a possible role in receptor desensitization.
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Affiliation(s)
- T Priestley
- Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex
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Affiliation(s)
- M H Humphreys
- Division of Nephrology, San Francisco General Hospital, California 94110
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Steer KA, Sochor M, Kunjara S, Doepfner W, McLean P. The effect of a somatostatin analogue (SMS 201-995, Sandostatin) on the concentration of phosphoribosyl pyrophosphate and the activity of the pentose phosphate pathway in the early renal hypertrophy of experimental diabetes in the rat. BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1988; 39:226-33. [PMID: 2454125 DOI: 10.1016/0885-4505(88)90080-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of a long-acting somatostatin analogue on the acute renal hypertrophy following induction of experimental diabetes in the rat has been studied. The kidney weight increase occurring at 2 and 7 days after alloxan injection was significantly lower in the diabetic group receiving somatostatin. Similarly, the previously reported increase in glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) found in the kidney at 2 and 7 days of diabetes was less marked in the group receiving SMS 201-995. The fall in renal phosphoribosyl pyrophosphate associated with early diabetic renal hypertrophy (7) was also lessened by administration of SMS 201-995. No effects of the drug were found in the normal rat on the same regimen of treatment. These observations indicate involvement of glucagon and/or growth hormone in the initiation of kidney growth in diabetes.
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Affiliation(s)
- K A Steer
- Department of Biochemistry, Middlesex Hospital Medical School, London, United Kingdom
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Simón MA, Calle C. Adrenergic receptors are not mediators in the lipolytic effect of somatostatin in rat adipocytes. Life Sci 1987; 41:2411-7. [PMID: 2891012 DOI: 10.1016/0024-3205(87)90666-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Beta-adrenergic receptors have been purported to act as possible mediators in the lipolytic effect of somatostatin in vivo. Investigations with isolated rat adipocytes studying the lipolytic activity of somatostatin (1.7 x 10(-7) M), glucagon (8.1 x 10(-8 M) and norepinephrine (10(-6) M), have shown that the lipolytic effect stimulated by somatostatin is not altered by 10(-5) M propranolol (beta-antagonist); is significantly enhanced by 10(-5) M isoproterenol (beta-agonist) and is not altered by the addition of 10(-6) M phenoxybenzamine (alpha-antagonist) or 10(-6) M phenylephrine (alpha-agonist). Similar results were found when lipolysis was stimulated by glucagon, whereas the lipolytic effect stimulated by norepinephrine was blocked by propranolol. These results indicate that the direct lipolytic effect of somatostatin on isolated rat adipocytes does not seem to be mediated through mechanisms involved with adrenergic receptors.
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Affiliation(s)
- M A Simón
- Department of Biochemistry, School of Medicine, Complutense University, Madrid
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Foote RW, Niemerich G. Weakening of naloxone antagonism in vitro and in vivo with octreotide (SMS 201-995). Eur J Pharmacol 1987; 141:325-30. [PMID: 2889609 DOI: 10.1016/0014-2999(87)90548-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Octreotide, a potent long-acting somatostatin analogue, has been shown to have a wide range of physiological actions. We have demonstrated a somatostatin-like inhibition of the electrically evoked contractions of the mouse vas deferens and an opioid antagonistic property in the same tissue. In addition, pretreatment with octreotide reduced the potency of naloxone antagonism in vitro in the mouse vas deferens and in vivo in the mouse charcoal meal test. The latter effect suggests that the agonist receptor interactions are taking place on sites allosteric to the agonist site and that the conventionally accepted concept of opioid antagonism may have to be modified.
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Affiliation(s)
- R W Foote
- Sandoz Ltd., Preclinical Research, Basel, Switzerland
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