Role of plasma insulin concentration in regulating glucose and lipid metabolism in lean and obese Zucker rats

It has been previously observed that the thermic effect of a glucose load is potentiated by prior exercise. To determine whether this phenomenon is observed when different carbohydrates are used and to ascertain the role of insulin, the thermic effects of fructose and glucose were compared during control (rest) and postexercise trials. Six male subjects ingested 100 g fructose or glucose at rest or after recovery from 45 min of treadmill exercise at 70% of maximal O2 consumption. Measurements of O2 consumption, respiratory exchange ratio, and plasma concentrations of glucose, insulin, glycerol, and lactate were measured for 3 h postingestion. Although glucose and fructose increased net energy expenditure by 44 and 51 kcal, respectively, over baseline during control trials, exercise increased the thermic effect of both carbohydrate challenges an additional 20-25 kcal (P less than 0.05). Glucose ingestion was associated with large (P less than 0.05) increases in plasma insulin concentration during control and exercise trials, in contrast to fructose ingestion. Because fructose, which is primarily metabolized by liver, and glucose elicited a similar postexercise potentiation of thermogenesis, the results indicate that the thermogenic phenomenon is not limited to skeletal muscle. These results also demonstrate that carbohydrate-induced postexercise thermogenesis is not related to an incremental increase in plasma insulin concentration.

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Development of pancreatic and plasma insulin in prenatal and suckling Zucker rats

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1982.242.4.e220 ◽

1982 ◽

Vol 242 (4) ◽

pp. E220-E225 ◽

Cited By ~ 2

Author(s):

I. J. Turkenkopf ◽

P. R. Johnson ◽

M. R. Greenwood

Keyword(s):

Lipoprotein Lipase ◽

Lipase Activity ◽

Plasma Insulin ◽

Metabolic Changes ◽

Insulin Concentration ◽

Zucker Rats ◽

Lipoprotein Lipase Activity ◽

Adipocyte Size ◽

Plasma Insulin Concentration ◽

Males And Females

Pancreatic and plasma insulin concentrations in preobese and lean Zucker rats were determined during three developmental periods: 1) gestation, 2) suckling, and 3) postweaning. Individual fetal samples were derived from two types of matings: 1) homozygous obese males (fafa) with heterozygous females (Fafa), and 2) homozygous lean males and females (FaFa). Suckling and postweaned pups from similar matings were partially pancreatectomized, tail bled, and identified retrospectively. In 21-day-old fetuses bearing the fa gene, plasma insulin concentration was elevated (P less than 0.001) and pancreatic concentration was slightly lower (P less than 0.05) compared to homozygous lean fetuses. Neither pancreatic nor plasma insulin concentration differed between preobese and lean pups during suckling, except that pancreatic concentration became elevated in preobese pups on postnatal day 20 (P less than 0.05). Plasma insulin concentration was elevated 24 h postweaning (P less than 0.01). These data support the hypothesis that the fa gene initiates metabolic changes during gestation that are modulated during suckling, but reappear at weaning. The data also establish that increased adipocyte size and lipoprotein lipase activity in 7- to 12-day-old preobese pups are not dependent on concomitant hyperinsulinemia.

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Lipid metabolism of orchiectomised rats was affected by fructose ingestion and the amount of ingested fructose

British Journal Of Nutrition ◽

10.1017/s0007114511003679 ◽

2011 ◽

Vol 107 (6) ◽

pp. 817-825

Author(s):

Satoru Makino ◽

Taro Kishida ◽

Kiyoshi Ebihara

Keyword(s):

Lipid Metabolism ◽

Plasma Insulin ◽

Uncoupling Protein ◽

Mrna Level ◽

Insulin Concentration ◽

Cholesterol Concentration ◽

Liver Cholesterol ◽

Maize Starch ◽

Plasma Insulin Concentration ◽

Faecal Excretion

We examined whether lipid metabolism in orchiectomised (ORX) rats was affected by fructose ingestion and the amount of ingested fructose. Sucrose was used as a fructose source. Sham-operated and ORX rats were fed one of the following three diets for 28 d: a maize starch-based diet without sucrose (SU0), a diet by which half or all of maize starch was replaced by sucrose (SU50 or SU100). Body-weight gain and food intake were increased by sucrose ingestion, but decreased by ORX. Plasma total cholesterol concentration was increased by ORX and dose-dependently by sucrose ingestion. Plasma TAG concentration was decreased by ORX, but was increased dose-dependently by sucrose ingestion. Plasma insulin concentration was decreased by ORX, but was not affected by sucrose ingestion. Liver TAG was increased by sucrose ingestion and ORX; however, liver cholesterol concentration was not affected by sucrose ingestion and ORX. The hepatic activity of cholesterol 7α-hydroxylase 1 was not affected by sucrose ingestion and ORX; however, faecal excretion of bile acids was decreased. The mRNA level of microsomal TAG transfer protein, which is the gene related to hepatic VLDL production, was increased by ORX and sucrose ingestion. The mRNA level of uncoupling protein-1 was decreased by ORX, but not by sucrose ingestion. Plasma insulin concentration tended to correlate with the level of sterol-regulatory element-binding protein-1c mRNA (r 0·747, P = 0·088). These results show that lipid metabolism in ORX rats would be affected by the consumption of fructose-rich sweeteners such as sucrose and high-fructose syrup.

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The parasympathetic nervous system and glucocorticoid-mediated hyperinsulinaemia in the genetically obese (fa/fa) Zucker rat

Journal of Endocrinology ◽

10.1677/joe.0.1180087 ◽

1988 ◽

Vol 118 (1) ◽

pp. 87-92 ◽

Cited By ~ 20

Author(s):

J. M. Fletcher ◽

N. McKenzie

Keyword(s):

Nervous System ◽

Plasma Glucose ◽

Plasma Insulin ◽

Parasympathetic Nervous System ◽

Insulin Concentration ◽

Zucker Rats ◽

Glucose Load ◽

Plasma Insulin Concentration ◽

Obese Rats ◽

Basal Plasma

ABSTRACT Lean (Fa/-) and genetically obese (fa/fa) Zucker rats were adrenalectomized at 18 days of age (3 days before weaning) before the onset of hyperinsulinaemia. At 40–41 days of age, basal and glucose-stimulated insulin concentrations did not differ significantly between lean and obese rats. Plasma insulin and glucose concentrations were higher in both phenotypes 24 h after administration of corticosterone (2·0 mg at 12-h intervals). Corticosterone-treated obese rats had higher basal and glucose-stimulated insulin levels than similarly treated lean animals, although plasma glucose concentrations did not differ between phenotypes. The basal plasma insulin concentration of obese rats treated with corticosterone for 24 h was reduced 15, 30 and 45 min after injection of atropine (0·3 mg) without any significant change in the plasma glucose level. Injection of atropine (0·3 mg) 20 min before a glucose load prevented the greater increment in plasma insulin concentration of corticosterone-treated obese rats compared with similarly treated lean animals. Atropine administration (0·3 mg) to intact obese rats at 40 days of age reduced, but did not abolish, their hyperinsulinaemia compared with intact lean animals. It is concluded that (1) pre-weaning adrenalectomy prevents the development of hyperinsulinaemia in genetically obese rats, (2) corticosterone replacement for only 24 h restores the hyperinsulinaemia of obese rats, (3) the differential effects of corticosterone on insulin secretion by lean and obese rats are mediated by the parasympathetic nervous system and (4) the parasympathetic nervous system contributes to, but is not the only cause of, hyperinsulinaemia in intact obese rats. J. Endocr. (1988) 118, 87–92

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Insulin clearance: an underappreciated modulator of plasma insulin concentration

Journal of Investigative Medicine ◽

10.1136/jim-2016-000149 ◽

2016 ◽

Vol 64 (7) ◽

pp. 1162-1165 ◽

Cited By ~ 16

Author(s):

Sun H Kim ◽

Gerald M Reaven

Keyword(s):

Plasma Glucose ◽

Plasma Insulin ◽

Narrow Range ◽

Physiological State ◽

Insulin Clearance ◽

Insulin Concentration ◽

Β Cells ◽

Plasma Insulin Concentration ◽

Insulin Secretion Rate

Plasma glucose concentrations are tightly regulated and maintained within a narrow range in non-diabetic individuals. Maintenance of this physiological state is primarily a function of the ability of the pancreatic β-cells to modify insulin secretion rate (ISR), thus preventing wide-swings in plasma glucose concentrations. As a consequence, and in contrast to plasma glucose concentrations, plasma insulin concentrations vary substantially in non-diabetic individuals. Although differences in ISR are primarily responsible for the variability in plasma insulin concentration, there is increasing evidence that differences in insulin clearance rate (ICR) also play a role in regulation of plasma insulin concentration. The goal of this mini-review is to highlight situations that demonstrate the important role of ICR in both insulin and glucose homeostasis.

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Effect of 5-Aminoimidazole-4-Carboxamide-1- -D-Ribofuranoside Infusion on In Vivo Glucose and Lipid Metabolism in Lean and Obese Zucker Rats

Diabetes ◽

10.2337/diabetes.50.5.1076 ◽

2001 ◽

Vol 50 (5) ◽

pp. 1076-1082 ◽

Cited By ~ 217

Author(s):

R. Bergeron ◽

S. F. Previs ◽

G. W. Cline ◽

P. Perret ◽

R. R. Russell III ◽

...

Keyword(s):

Lipid Metabolism ◽

Zucker Rats ◽

Glucose And Lipid Metabolism ◽

Obese Zucker Rats

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146 Nutritional Advances in Fetal and neonatal development: effect of fatty acid supplementation

Journal of Animal Science ◽

10.1093/jas/skaa054.207 ◽

2020 ◽

Vol 98 (Supplement_3) ◽

pp. 121-122

Author(s):

Alejandro E Relling

Keyword(s):

Small Intestine ◽

Fatty Acid ◽

Plasma Insulin ◽

Linear Increase ◽

Late Gestation ◽

Insulin Concentration ◽

Plasma Insulin Concentration ◽

Pufa Supplementation ◽

Epa And Dha ◽

Offspring Growth

Abstract Data from a series of experiments demonstrates that maternal supply of polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), during late gestation affects offspring growth. The increase in growth is independent on the fatty acid supplemented during the growing or finishing phase of the offspring; but it is sex dependent. Dam PUFA supplementation increases wether growth. Supplementation with EPA and DHA to pregnant ewes and to their offspring after weaning showed a treatment interaction in mRNA concentration of hypothalamic neuropeptides associated with dry matter intake (DMI) regulation. A dose increased in EPA and DHA in pregnant ewe diets shows a linear increase in growth, but a quadratic change in DMI or feed efficiency; growth was associated with a linear increase in plasma glucose concentration and a linear decrease in plasma ghrelin concentration. In lambs born from ewes supplemented with different sources of FA during a glucose tolerance test; males’ plasma insulin concentration increased as FA unsaturation degree increased in the dam diet, the opposite happened with females’ plasma insulin concentration. Recent data from our lab showed that the supplementation with EPA and DHA during the last third of gestation to pregnant ewes increased liver and small intestine global DNA methylation and small intestine transporters for amino acids in the fetus. Despite EPA and DHA during late gestation increase growth in the offspring; when EPA and DHA were supplemented in early gestation, offspring growth was lesser that lambs born from ewes supplemented a saturated and monounsaturated lipid. The reason for the difference in results it is not clear. However, more studies focusing in some aspect of the biology will help to understand what specific fatty acid needs to be supplemented at different stages of gestation to improve offspring growth.

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