Variation de I’insulinémie en fonction de I’âge chez le rat mâle non traité

Abstract

Effect of ageing on insulinemia, determined by radio-immunological method, has been studied in male rats aged 3, 12 and During the intravenous hyperglycemia test, the coefficient of glucose assimilation decreases significantly with age, whereas a hype insulinemia is to be seen. This becomes apparent at the moment of the hyperglycemic peak and still persists 20 min after the beginning of the test. Senescence in the rat is, therefore, accompanied by early decrease in glucose tolerance and abnormally high IRI (immunoreactive insulin) level in the blood.

The effect of glucose on insulin release and ion movements in isolated pancreatic islets of rats in old age.

“…During old age, hyperglycemia and/or deterioration of glucose tolerance have been reported to occur in rats (Gommers & De Gasparo, 1972;Gommers & Genne, 1975;Bracho-Romero & Reaven, 1977) and in man (O' Sullivan, Mahan, Freedlender & Williams, 1971;Sandberg, Yoshimine, Maeda, Symons & Zavodnick, 1973;Dudl & Ensinck, 1977;Defronzo, 1979). A major factor which may contribute to this phenomenon has been suggested to be a diminished insulin secretory response of the pancreatic B cell (Reaven, Gold & Reaven, 1979;Lipson, Bobrycki, Bush, Tietjen & Yoon, 1981;Molina, Premdas & Lipson, 1985).…”

Adipocyte Hormone Responsiveness and Aging in the Rat: Problems in the Interpretation of Aging Research

“…Corticosterone levels may increase with age in the rat, 41 and adrenal steroids are known to affect catecholamine and ACTH‐stim‐ulated lipolysis 3,23 . Whether senescence in rodents is accompanied by an increase 44,48 or a reduction 49 in circulating insulin levels is uncertain and may depend on feeding patterns and the time of sampling, but glucose tolerance appears to decline 48,50 . Insulin and glucose levels affect lipogenesis and lipolysis 2,20 .…”

“…Corticosterone levels may increase with age in the rat,41 and adrenal steroids are known to affect catecholamine and ACTH-stimulated l i p~l y s i s .~,~~ Whether senescence in rodents is accompanied by an or a reduction49 in circulating insulin levels is uncertain and may depend on feeding patterns and the time of sampling, but glucose tolerance appears to decline. 48,50 Insulin and glucose levels affect lipogenesis and lipolysis.2,20 Thyroxine,22 TSH,lg ACTH,51-53 glucagon, l9 prostaglandin,20 and plasma lipoprotein levels% all affect fat tissue metabolism in the rat and may change with age. It is difficult to separate the effects of changing extracellular hormonal influences from the intrinsic effects of aging.…”

Age‐related immunohistochemical studies of A and D cells in pancreatic islets of C57BL/6J mice

“…Aging often has been correlated with physiological abnormalities in glucose homeostasis. Deterioration of glucose tolerance has been reported in aged rats (Klimas, 1968;Gommers and de Gasparo, 1972;Bracho-Romero and Reaven, 1977) and humans (Andres, 1971;O'Sullivan et al, 19711, reflecting either defective insulin secretion, defective islet sensitivity to glucose, or insulin resistance (Davidson, 1979;Defronzo, 1979;Olefsky, 1981;Draznin et al, 1985;Elahi et al, 1985;Sartin et al, 1986). In some strains of mice (NMRI and C57BL/KSJ), aging has been correlated with increased insulin secretion using the whole perfused pancreas as the model (Bonnevie-Nielsen et al, 1983).…”