Evolution metabolique en fonction de l'age chez le rat: Role de l'insuline

The aim of our work was to study the developmental changes in plasma and hepatic concentrations of carbohydrates, lipids, and proteins in "Wistar" rats between prepartum day 1 [fetus considered J-1] and postpartum day 133 [adult considered j+133]. In addilion, the evolution of insulinemia has been examined. The 2 1 day aged fetus [j-1], as compared to the adult [j+1 33] showed a lower glycemia, a higher stock of hepatic glycogen, lower rates of lipids and proteins in the plasma and in the liver. The fetol insulinemia was significantly higher than adult's. After the delivrance we have attended to an increase of the glycemia and a very marked deplelion of the glycogenic stock in the liver. The plasma and hepatic lipids and proteins rose after birth. The insulinemia fell considerably and reached the lowest level. Between the 14th and 30'" day of the postnatal life, a restoration of the stock of the hepatic gtycogen, a normal glycemia, an elevation of the plasma and hepatic rates of proteins, and a decrease of the lipidic levels in plasma and liver were recorded. In addition the concentration of insulin increased during this period. All these values remained steady during the adult stage. We conclude that the development of rat

Effect du jeune sur la glycemie et la proteinemie chez le rat jeune et adulte

The aim of Our work has consisted of studying the effects of a severe three- day fast on the evolution of the body weight, on glycemia and on proteinemia among the young and mature male rate. The decrease in body weight which is more marked among young rats after starvation shows that the loss of body mass due to fasting decreases with the age of the rats. The physiological perturbations of nutritive constants that have been recorded during this period of fast show that the mature rat first attacks its non-protein stocks or glucides, which leads to a decrease in its glycemia and in its lipids; whereas the young rat uses its proteins after only three days of starvation because of its small stock of lipids

Effects of age and dehydration on the activity of the vasopressinergic axis in rats

The aim of our work was to study the different blood parameters as well as the activity of the vasopressinergic axis in young and mature male rats under normal conditions and following a 3-day dehydration cycle by water deprivation. Under normal conditions, our study demonstrates higher levels of vascopressin in mature rats as compared to young rats. This could be due in part to the higher blood osmolality in the mature rats. After dehydration, hyprovolemia, plasmatic hyperosmolaity, hypernatremia and hyperproteinemia cause a stimulation in vassopression synthesis and release, as seen in results obtained from the hypothalamus, hypophysis and plasma in both young and mature rats. However, the response of the vasopressinergic axis to dehydration is greater in young rats, suggesting a more pronouncd sensitivity to osmotic factors