Comparative effects of adrenaline and noradrenaline on the synthesis and secretion of soluble protein by isolated hepatocytes

Abstract

1. 1. Adrenaline (A) supplementation of the incubation medium of monolayer cultures of hepatocytes at 0.1, 0.2, 0.3, 1 and 10 ng/ml resulted in consistently enhanced levels of secreted and newly synthesised non-secreted proteins; supplementation with 100 and 1000 ng/ml resulted in lower or unchanged levels. These effects were most consistent 6 hr after a medium change. 2. 2. Noradrenaline supplementation of the medium resulted in increased levels of secreted and non-secreted proteins at low concentrations (<2.4 ng/ml) at 6 hr after a medium change, but significantly decreased levels of both populations at high concentrations of noradrenaline (NA) (2.4 < NA < 1000 ng/ml), at 6–9 hr after a medium change and sustained to 24 hr, the most significant decrease being at 10 ng/ml. 3. 3. All combinations of concentrations of A + NA resulted in non-dose-dependent decreased levels of both the secreted and non-secreted soluble protein fractions. The most significant decreases occurred at concentrations of (1 + 5) and (10 + 10) ng/ml adrenaline + noradrenaline. 4. 4. Medium supplementation with adrenaline, noradrenaline or a combination of the two had no effect on the uptake of [ 3H]leucine by the cells. 5. 5. The results are discussed in relation to receptor status on the hepatocyte membranes.