Effect of Starvation on Nutrition and Insulin Secretion in Pregnant Rats and their Fetuses.

Tanigawa, Keiichiro; Ohguni, Satoshi; Masaki, Yohji; Tsuchiyama, Shinichi; Kawaguchi, Mikiko; Kato, Yuzuru

doi:10.1507/endocrj1954.36.195

Cited by 5 publications

(1 citation statement)

References 14 publications

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“…Indeed, development of insulin resistance during pregnancy may protect the mother from the deleterious effect of a lack of insulin (25,26). In addition, elevated ketones are redistributed to the fetus to be used as fuel, which may be less deleterious to the mother (27,28). The mating day was considered as day 1 of gestation and STZ injection.…”

Section: In Vivo Studies In Ratsmentioning

confidence: 99%

In Vivo and in Vitro Regulation of Hepatic Glucagon Receptor mRNA Concentration by Glucose Metabolism

Burcelin¹,

Mrejen²,

Decaux³

et al. 1998

Journal of Biological Chemistry

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We have recently cloned the murine glucagon receptor (GR) gene and shown that it is expressed mainly in liver. In this organ, the glucagon-GR system is involved in the control of glucose metabolism as it initiates a cascade of events leading to release of glucose into the blood stream, which is a main feature in several physiological and pathological conditions. To better define the metabolic regulators of GR expression in liver we analyzed GR mRNA concentration in physiological conditions associating various glucose metabolic pathways in vivo and in vitro in the rat and in the mouse. First, we report that the concentration of the GR mRNA progressively increased from the first day of life to the adult stage. This effect was abolished when newborn rodents were fasted. Second, under conditions where intrahepatic glucose metabolism was active such as during fasting, diabetes, and hyperglycemic clamp, the concentration of GR mRNA increased independent of the origin of the pathway that generated the glucose flux. These effects were blunted when hyperglycemia was corrected by phlorizin treatment of diabetic rats or not sustained during euglycemic clamp.In accordance with these observations, we demonstrated that the glycolytic substrates glucose, mannose, and fructose, as well as the gluconeognic substrates glycerol and dihydroxyacetone, increased the concentration of GR mRNA in primary cultures of hepatocytes from fed rats. Glucagon blunted the effect of glucose without being dominant. The stimulatory effect of those substrates was not mimicked by the nonmetabolizable carbohydrate L-glucose or the glucokinase inhibitor glucosamine or when hepatocytes were isolated from starved rats. In addition, inhibitors of gluconeogenesis and lipolysis could decrease the concentration of GR mRNA from hepatocytes of starved rats. Combined, these data strongly suggest that glucose flux in the glycolytic and gluconeogenic pathways at the level of triose intermediates could control expression of GR mRNA and participate in controlling its own metabolism. The glucagon receptor (GR)1 is a 63,000-Da plasma membrane protein that belongs to a subfamily of peptide hormone receptors (1, 2). All members of this family contain seven transmembrane domains and are coupled with GTP-binding proteins. Upon binding to its receptor, glucagon initiates its action by activating several GTP-binding proteins which are ratelimiting steps in various signal transduction cascades (3-12).The GR gene is expressed mainly in liver (2,8,13,14) where it initiates a cascade of events leading to synthesis and release of glucose into the blood stream (15). Hepatic glucose production represents a major process in several physiological and pathological conditions. In newborns, glucagon is secreted within an hour of parturition and initiates several processes leading to hepatic glucose production (16) from glycogenolysis and gluconeogenesis (17). Then, during suckling glucagon stimulation ensures hepatic synthesis of glucose, which is otherwise poorly provided by mother's...

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Section: In Vivo Studies In Ratsmentioning

confidence: 99%

In Vivo and in Vitro Regulation of Hepatic Glucagon Receptor mRNA Concentration by Glucose Metabolism

Burcelin¹,

Mrejen²,

Decaux³

et al. 1998

Journal of Biological Chemistry

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Role of 17-β-estradiol and progesterone on glucose homeostasis: Effects of food restriction (50%) in pregnant and non pregnant rats

et al. 1997

J Endocrinol Invest

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The role of 17-beta-estradiol and progesterone on glucose homeostasis was examined in pregnant and non pregnant rats with or without food restriction (50%). Blood glucose and insulin levels were significantly decreased in food restricted pregnant (PM) compared with control pregnant (PC) and in food restricted non pregnant (M) compared with non pregnant control (C). The plasmatic level of progesterone was similar in PC and PM, while the plasmatic level of 17-beta-estradiol was significantly decreased in PM compared with PC at 15 and 20 days. In spite of food restriction, the changes in the insulin/glucose ratio throughout gestation were similar in PC and PM. A positive and significant relation between 17-beta-estradiol and the level of insulin at day 5 of gestation, and a negative and significant relation between the level of 17-beta-estradiol and level of insulin at day 15 of gestation were found in PC. A negative and significant relation between the levels of progesterone and the levels of insulin at day 5 of gestation, at day 10 this relation is positive and significative, and at day 15 a positive and significant relation exists between levels of 17-beta-estradiol and levels of insulin were found in PM. These results suggest that 17-beta-estradiol acts directly on beta-cells to control insulin secretion. Food restriction does not alter the changes in the sensitivity of tissues to the insulin action, and does modify the action of 17-beta-estradiol and progesterone on beta-cell.

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Effect of pregnancy on insulin metabolism in spontaneously hyperensive rats

et al. 1999

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Effect of Starvation on Nutrition and Insulin Secretion in Pregnant Rats and their Fetuses.

Cited by 5 publications

References 14 publications

In Vivo and in Vitro Regulation of Hepatic Glucagon Receptor mRNA Concentration by Glucose Metabolism

In Vivo and in Vitro Regulation of Hepatic Glucagon Receptor mRNA Concentration by Glucose Metabolism

Role of 17-β-estradiol and progesterone on glucose homeostasis: Effects of food restriction (50%) in pregnant and non pregnant rats

Effect of pregnancy on insulin metabolism in spontaneously hyperensive rats

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