Influence de l'hyperinsulinémie sur les récepteurs d'insuline dans le foie du rat en croissance soumis à une restriction énergétique

Abstract

Influence de l'hyperinsulinémie sur les récepteurs d'insuline dans le foie du rat en croissance soumis à une restriction énergétique

Glucagon binding to purified liver plasma membranes from growing rats undergoing energy restriction

“…Another possibility would be that hormones other than glucagon vary. Feeding the experimental diet also induced a small increase in insulin binding to liver plasma membranes (Grizard, Arnal and Pion, 1980). These results are in keeping with the increase in protein anabolism observed in livers from such animals (Arnal et al, 1972) since glucagon produces a drop in liver protein anabolism (Ayuso-Parrilla et al, 1976 ;Martin-Requero et al, 1979), whereas insulin promotes it (Bellemann et al, 1977 …”

“…These changes indicate that there may also be variations in the hormonal mechanisms controlling protein metabolism in liver and muscle. For example, blood insulin decreases but liver insulin receptors increase in growing rats (Grizard, Arnal and Pion, 1980). Some of the present work has been reported previously in an abstract (Balage and Grizard, 1981 ( -34, -44 and -34 %, respectively).…”

“…Therefore, the drop in apparent specific !z51_glucagon binding per mg of purified liver plasma membranes could be explained by a drop in membrane purity. Alternatively, 5'-nucleotidase activity could have decreased as a result of energy restriction (Grizard, Arnal and Pion, 1980 The decrease in glucagon binding to its receptors after feeding the experimental diet correlates with the decrease in glucagon binding found in fasted rats (Fouchereau-Peron et al, 1976 ;Broer et al, 1977 ;Caro and Amatruda, 1980 ;Srikant et al, 1977 ;Freeman et al, 1977). It contrasts with the constant, glucagon binding to isolated hepatocytes found in restricted goats (Gill and Hart, 1979 ;Gill and Hart, 19811.…”

“…the growth rate/crude protein intake ratio) was highly impaired, suggesting an increased rate of amino acid breakdown and gluconeogenesis (Grizard et al, 1975). The control and the high-protein diets, which have been described previously (Grizard et al, 1975 ;Grizard, Arnal and Pion, 1980) (Broer et al, 1977 ;Gill and Hart, 1980 Characteristics of plasma membrane preparations. ― Recovery of glucose-6-phosphatase from membrane preparations was low, indicating that there was no microsomal contamination (table 4).…”