Pulsatile secretion of growth hormone and insulin in relation to feeding in rats

1987 ◽  
Vol 253 (5) ◽  
pp. R772-R778
Author(s):  
P. Even ◽  
J. Danguir ◽  
S. Nicolaidis ◽  
C. Rougeot ◽  
F. Dray
Keyword(s):  
Growth Hormone ◽  
Insulin Secretion ◽  
Food Intake ◽  
Wistar Rats ◽  
Plasma Concentrations ◽  
Endocrine Activity ◽  
Blood Samples ◽  
Gh Secretion ◽  
Male Wistar Rats ◽  
Intracardiac Catheters

In unrestrained male Wistar rats chronically implanted with intracardiac catheters, blood samples were taken every 20 min throughout the 24 h of the diurnal cycle. Plasma concentrations of growth hormone (GH), insulin, and glucose were measured. The pattern of food intake was continuously monitored. The existence of 3-h pulsatile cycles of GH secretion was confirmed. In addition, short bursts of insulin secretion were observed in the middle of every second GH peak-to-peak interval. Food intake appeared to be enhanced during short periods that corresponded with GH release into the blood and was reduced during the GH peak-to-peak periods in which the bursts of insulin secretion were observed. From these observations this study draws a schematic relationship between the rhythmicity of the secretion of GH and insulin and the probability of occurrence of feeding. We speculate that the rhythmic endocrine activity may be causally related to feeding.

Characterization of feeding behavior induced by central injection of GRF

1990 ◽  
Vol 259 (3) ◽  
pp. R651-R657 ◽  
Author(s):  
P. R. Dickson ◽  
F. J. Vaccarino
Keyword(s):  
Growth Hormone ◽  
Food Intake ◽  
Suprachiasmatic Nucleus ◽  
Paraventricular Nucleus ◽  
Wistar Rats ◽  
Preoptic Area ◽  
Behavioral Responses ◽  
Behavioral Measures ◽  
Male Wistar Rats

The behavior resulting from injection of rat hypothalamic growth hormone-releasing factor (GRF) (0, 0.01, 0.1, 1.0 pmol) into the suprachiasmatic nucleus-medial preoptic area (SCN/MPOA) or the paraventricular nucleus (PVN) of the hypothalamus was examined. After injections of GRF, feeding and other behavioral responses of male Wistar rats were observed for 90 min. In the SCN/MPOA, GRF dose dependently increased food intake, increasing mean meal length at 0.1 pmol and increasing rate of eating with no effect on meal length at 1.0 pmol. Other behavioral measures were unaffected by GRF. There was no effect after injections into the PVN. These data are taken as confirmation that the SCN/MPOA region of the hypothalamus is important for the central stimulatory effects of GRF on feeding. The possibility that the PVN is involved in the expression of feeding derived from intra-SCN/MPOA GRF injections is discussed.

Reduction of enantioselectivity in the kinetic disposition and metabolism of verapamil in rats exposed to toluene

2008 ◽  
Vol 86 (5) ◽  
pp. 232-239 ◽  
Author(s):  
F.H. Mateus ◽  
J.S. Lepera ◽  
M.P. Marques ◽  
V.B. Boralli ◽  
V.L. Lanchote
Keyword(s):  
Single Dose ◽  
Oxidative Metabolism ◽  
Wistar Rats ◽  
Plasma Concentrations ◽  
Wilcoxon Test ◽  
Control Group ◽  
Chiral Drugs ◽  
Blood Samples ◽  
Male Wistar Rats ◽  
Air Control

Toluene and verapamil are subject to extensive oxidative metabolism mediated by CYP enzymes, and their interaction can be stereoselective. In the present study we investigated the influence of toluene inhalation on the enantioselective kinetic disposition of verapamil and its metabolite, norverapamil, in rats. Male Wistar rats (n = 6 per group) received a single dose of racemic verapamil (10 mg/kg) orally at the fifth day of nose-only toluene or air (control group) inhalation for 6 h/day (25, 50, and 100 ppm). Serial blood samples were collected from the tail up to 6 h after verapamil administration. The plasma concentrations of verapamil and norverapamil enantiomers were analyzed by LC-MS/MS by using a Chiralpak AD column. Toluene inhalation did not influence the kinetic disposition of verapamil or norverapamil enantiomers (p > 0.05, Kruskal–Wallis test) in rats. The pharmacokinetics of verapamil was enantioselective in the control group, with a higher plasma proportion of the S-verapamil (AUC 250.8 versus 120.4 ng·h·mL–1; p ≤ 0.05, Wilcoxon test) and S-norverapamil (AUC 72.3 versus 52.3 ng·h·mL–1; p ≤ 0.05, Wilcoxon test). Nose-only exposure to toluene at 25, 50, or 100 ppm resulted in a lack of enantioselectivity for both verapamil and norverapamil. The study demonstrates the importance of the application of enantioselective methods in studies on the interaction between solvents and chiral drugs.

Augurin stimulates food intake in male Wistar rats

2013 ◽  
pp. 1-1
Author(s):  
Michael Patterson ◽  
John Tadross ◽  
Keisuke Suzuki ◽  
Kylie Beale ◽  
Charoltte Boughton ◽  
...  
Keyword(s):  
Food Intake ◽  
Wistar Rats ◽  
Male Wistar Rats

scholarly journals Intense physical exercise potentiates glucose inhibitory effect over food intake of male Wistar rats

2018 ◽  
Vol 103 (8) ◽  
pp. 1076-1086 ◽  
Author(s):  
João Paulo Cavalcanti-de-Albuquerque ◽  
Grasielle Clotildes Kincheski ◽  
Ruy Andrade Louzada ◽  
Antônio Galina ◽  
Anna Paola Trindade Rocha Pierucci ◽  
...  
Keyword(s):  
Food Intake ◽  
Physical Exercise ◽  
Wistar Rats ◽  
Inhibitory Effect ◽  
Male Wistar Rats

Disturbances of growth hormone-insulin-like growth factor axis and response to growth hormone in acidosis

1998 ◽  
Vol 275 (1) ◽  
pp. R120-R128
Author(s):  
Karina Jandziszak ◽  
Carlos Suarez ◽  
Ethan Wasserman ◽  
Ross Clark ◽  
Bonnie Baker ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Food Intake ◽  
Linear Growth ◽  
Growth Failure ◽  
Serum Levels ◽  
Igf Binding Proteins ◽  
Gh Secretion ◽  
Term Administration ◽  
Igf Binding ◽  
Final Length

Severe chronic metabolic acidosis (CMA) in rats is associated with poor food intake and downregulation of growth hormone (GH), insulin-like growth factors (IGFs), and liver receptors; the administration of recombinant GH (rGH) fails to improve the growth failure. In mice with carbonic anhydrase II deficiency (CAD), a model of moderate CMA with food intake close to normal, we studied serum levels of GH, IGFs, and IGF-binding proteins, and the growth response to rGH. CAD was associated with low serum levels of GH in males. Randomized administration of rGH from ∼5 to ∼12 wk to CAD mice improved food efficiency and increased serum IGF-I levels, final length, and weight compared with placebo without affecting blood pH. Although administration of rGH also increased linear growth in healthy animals, the effect was less than that in CAD mice and was only observed when started before 6 wk of life. Thus growth failure in CAD mice is associated with a decrease in GH secretion in males but not in females. Long-term administration of rGH increases linear growth in CAD mice despite persistent CMA.

scholarly journals The effect of dietary protein source and guar gum on gastrointestinal growth and enteroglucagon secretion in the rat

1987 ◽  
Vol 58 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Susan Southon ◽  
Jennifer M. Gee ◽  
I. T. Johnson
Keyword(s):  
Dietary Protein ◽  
Wistar Rats ◽  
Guar Gum ◽  
Protein Source ◽  
Endocrine Activity ◽  
Intestinal Length ◽  
Daily Food ◽  
Male Wistar Rats ◽  
Small Intestinal ◽  
Dietary Protein Source

1. Male Wistar rats (approximately 100 g) were given fibre-free semi-synthetic diets containing either casein or albumin (168 g/kg diet) as the protein source with or without guar gum (75 g/kg diet) (casein, albumin, casein- guar gum and albumin-guar gum groups).2. Small intestinal length, weights of caecal tissue and contents and plasma enteroglucagon concentration were significantly increased in guar-gum-fed animals compared with the fibre-free groups.3. Total caecal weight and plasma enteroglucagon concentration were higher in the albumin-guar gum group compared with the casein-guar gum group. The weights of caecal tissue and contents were significantly increased in rats given the fibre-free albumin diet compared with those consuming a similar diet with casein as the protein source, although daily food intake tended to be lower.4. It is concluded that the effect of materials classed as dietary fibre may be significantly influenced by the non- polysaccharide component of the diet, and that such interactions may influence both the growth and endocrine activity of the gastrointestinal tract.

Central action of thyrotrophin-releasing hormone on growth hormone secretion in domestic fowl

1990 ◽  
Vol 126 (1) ◽  
pp. 83-88 ◽  
Author(s):  
S. Harvey ◽  
R. W. Lea ◽  
C. Ahene
Keyword(s):  
Growth Hormone ◽  
Domestic Fowl ◽  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Growth Hormone Secretion ◽  
Central Effect ◽  
Central Action ◽  
Thyrotrophin Releasing Hormone ◽  
Gh Secretion ◽  
Peripheral Plasma

ABSTRACT Peripheral plasma concentrations of GH in adult chickens were increased, in a dose-related manner, between 5 and 30 min after the intracerebroventricular (i.c.v.) injection of 0·1 or 10 μg TRH. In contrast, i.v. administration of comparable doses of TRH had no significant effect on circulating GH concentrations. [3H]3-methyl-histidine2-TRH ([3H]Me-TRH) was located in the pituitary gland and peripheral plasma within 5 min of its i.c.v. administration, although in amounts that were unlikely to affect directly pituitary function. [3H]Me-TRH rapidly accumulated in the hypothalamus following its i.c.v. administration (but not after i.v. injection), and the central effect of TRH on GH secretion in birds is therefore likely to be induced by effects at hypothalamic sites. Journal of Endocrinology (1990) 126, 83–88

scholarly journals D-Pinitol from Ceratonia Siliqua Is an Orally Active Natural Inositol That Reduces Pancreas Insulin Secretion and Increases Circulating Ghrelin Levels in Wistar Rats

2020 ◽  
Author(s):  
Juan Antonio Navarro ◽  
Juan Decara ◽  
Dina Medina-Vera ◽  
Ruben Tovar ◽  
Juan Suarez ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Signaling ◽  
Wistar Rats ◽  
Glycolytic Enzyme ◽  
Rapid Absorption ◽  
Male Wistar Rats ◽  
Oral Pharmacokinetics ◽  
Orally Active ◽  
Active Natural ◽  
Potential Use

To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analysed its oral pharmacokinetics and its effects on a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), b) insulin signaling in the liver and c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associate with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation while sustaining glycaemia through liver-based mechanisms of glycolysis control.

scholarly journals Protective role of melatonin against adipose-hepatic metabolic comorbidities in experimentally induced obese rat model

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260546
Author(s):  
Mary J. Obayemi ◽  
Christopher O. Akintayo ◽  
Adesola A. Oniyide ◽  
Ayodeji Aturamu ◽  
Olabimpe C. Badejogbin ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Insulin Resistance ◽  
Food Intake ◽  
High Fat Diet ◽  
Wistar Rats ◽  
Liver Lipid ◽  
Control Group ◽  
Metabolic Dysfunction ◽  
High Fat ◽  
Male Wistar Rats

Background Adipose and hepatic metabolic dysfunctions are critical comorbidities that also aggravate insulin resistance in obese individuals. Melatonin is a low-cost agent and previous studies suggest that its use may promote metabolic health. However, its effects on some comorbidities associated with obesity are unknown. Herein, we investigated the hypothesis that melatonin supplementation would attenuate adipose-hepatic metabolic dysfunction in high fat diet (HFD)-induced obesity in male Wistar rats. Materials and methods Twenty-four adult male Wistar rats (n = 6/group) were used: Control group received vehicle (normal saline), obese group received 40% high fat diet, melatonin-treated group received 4 mg/kg of melatonin, and obese plus melatonin group received 40% HFD and melatonin. The treatment lasted for 12 weeks. Results HFD caused increased food intake, body weight, insulin level, insulin resistance and plasma and liver lipid but decreased adipose lipid. In addition, HFD also increased plasma, adipose and liver malondialdehyde, IL-6, uric acid and decreased Glucose-6-phosphate dehydrogenase, glutathione, nitric oxide and circulating obestatin concentration. However, these deleterious effects except food intake were attenuated when supplemented with melatonin. Conclusion Taken together, the present results indicate that HFD exposure causes adipose-hepatic metabolic disturbance in obese animals, which are accompanied by oxidative stress and inflammation. In addition, the present results suggest that melatonin supplementation attenuates adipose-hepatic metabolic dysfunction, accompanying obesity by suppression of oxidative stress/inflammation-dependent mechanism and increasing circulating obestatin.

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