Interaction of 5-azacytidine and dexamethasone in the control of hepatic tyrosine aminotransferase.

The nucleoside analog 5-azacytidine is able to induce tyrosine aminotransferase several-fold in the liver of suckling rats. Bilateral adrenalectomy abolishes this inducing effect. The drug also decreases significantly the concentration of cytosolic glucocorticoid receptor accompanied by an increase of the glucocorticoid receptor concentration in the nuclei.

[Age-dependent reproductive performance of Shoe:WIST rats].

Reproductive performance of fertile female Shoe: WIST rats decreases with increasing age. The decreases in productivity and litter size of the females do not depend on the age of the male. Circannual investigation exhibits a significant depression of reproductive performance in autumn of all the age groups.

Influence of the placenta on fetal plasma insulin and neonatal hepatic enzyme induction in the rat.

In order to study the placental role in controlling glucose metabolism and neonatal induction of tyrosine aminotransferase in rat liver, a comparison was made between the artificially delivered-rat feto-placental unit and the newborn littermates. The immunoreactive serum insulin in the feto-placental unit remains as high as in utero for at least 1 h whereas in the newborn rat it decreases rapidly after delivery. From Caesarian section to 6 h later, in contrast to the newborn littermates, the feto-placental unit remains hyperglycaemic.

Effect of prenatal insulin and glucagon injection on the glycogen content of rat placenta and fetal liver.

The placental glycogen content per g wet weight decreases after the 16th day of gestation but remains nearly constant till the 21st day of gestation when expressed per placenta as whole organ. Injection of insulin to rat fetuses at the 21st day of gestation gives rise to hypoglycemia and an increase of the glycogen content in liver and in placenta. Intrauterine glucagon application makes fetuses hyperglycemic in consequence of a mobilization of the placental glycogen stores.

Interaction of adrenal and pancreatic hormones in the control of hepatic enzymes during development.

In the liver of suckling rats, the synthesis of hepatic tyrosine aminotransferase, serine dehydratase, and phosphofructokinase 2 as well as of renal beta-glucosidase is controlled by the circulating concentrations of adrenal and pancreatic hormones. Glucagon is capable of stimulating enzyme synthesis only in the presence of a steroid hormone. Dexamethasone and estradiol have been found to exert a permissive function on the inducibility of the studied enzymes by glucagon.