Insulin Receptors in Developing Rat Liver

Abstract

The development of insulin receptors and insulin-stimulated receptor autophosphorylation were studied in livers of prenatal and neonatal rats. Insulin receptors were present in mid-gestation, as early as day 14 in fetal development (full term is 22 days in the rat), with ligand-activated receptor kinase present. In contrast, insulin-stimulated phosphorylation of a M_r 120 kd glycoprotein derived from rat liver membranes, known as ppl20/HA4 and more recently identified as ecto-ATPase, was not observed in fetal liver until day 17 of gestation. Thereafter, phosphorylation of pp120/HA4 increased throughout late gestation. The data suggest that maturation of the insulin receptor kinase occurs soon after initial appearance of the receptor in mid-gestation, but insulin-stimulated phosphorylation of endogenous substrate(s) is dependent on the appearance of specific substrates, such as pp120/HA4.

Prolonged effect of an H1‐receptor blocker antihistamine on the histamine content of white blood cells and mast cells

“…1 During this process, perinatally, the first encounter between the receptor and its target hormone provokes the phenomenon of hormonal imprinting. 2,3 This encounter is needed for the normal completion of receptor maturation to reach the normal binding capacity of the receptor and appropriate response of the cell.…”

Contraceptive Treatment Increases the Affinity of Uterine Estrogen Receptor in Adult Rat

“…The hormone receptors of mammals are immature in the perinatal period (Blazquez, Rubalcava, Montesano and Unger 1976;Margolis, Tanner, Seminara and Taylor 1990) and mature only in the presence of the adequate hormone (Csaba 1980). Hormonal imprinting (Csaba 1980) that takes place at primary interaction of target cells with the adequate hormone accounts for receptor maturation (Csaba 1981;1984;1994) and the binding capacity of receptors as well as the response of the cell become characteristic to that of the receptor-hormone reaction at the adult age.…”