J. Ho

Synthesis of VLDL by isolated rat hepatocytes in suspension

Abstract Very low density lipoprotein (VLDL) synthesis was studied using suspensions of isolated rat hepatocytes prepared and incubated as described previously (1). These hepatocytes synthesized and secreted VLDL over a 24-hr period, in quantities permitting its isolation, without using carrier, for determining absolute synthesis rates and analysing the peptide pattern. The mean secretion of triglyceride, cholesterol and rat VLDL protein was 410 ± 46.6, 36.6 ± 0.1 and 34.9 ± 5.4 (mean ± SEM, n = 5) μg/g hepatocyte/hr over 24 hr, during which incorporation of 3H-valine into VLDL protein approached linearity. Suitable polyacrylamide gel electrophoresis showed the hepatocytes secreted the peptides found in circulating rat VLDL but with a different proportion of the fast to the slowly migrating ones.

Isolated rat hepatocytes as a model to study drug metabolism: dose-dependent metabolism of diphenylhydantoin.

Abstract The metabolism of diphenylhydantoin (DPH) was studied using isolated rat hepatocytes. The V max of DPH metabolism when calculated from the disappearance of DPH in the medium was 0.39 to 0.48 μmole/g cell/hr which is comparable to that in microsomal preparations. Disappearance rate of DPH was concentration-dependent but not of a simple Michaelis-Menten type. The formation of a DPH metabolite (glucuronide of hydroxylated DPH, HPPH-G) has an apparent V max of 0.29 to 0.32 μmole/g cell/hr. DPH binds extensively to hepatocytes and its distribution between the hepatocytes and the suspension medium was independent of DPH concentration.

The Effect of Ethanol on Albumin and Fibrinogen Synthesis In Vivo and in Hepatocyte Suspensions

Publisher Summary This chapter discusses the effect of ethanol on albumin and fibrinogen synthesis in vivo and in hepatocyte suspensions. An important and specific function of the endoplasmic reticulum of the hepatocyte is the synthesis of plasma proteins so that a specific hepatotoxic effect of ethanol likely ought to be reflected by a concurrent change in plasma protein synthesis. Furthermore, as the synthesis of these proteins occurs on ribosomes attached to the rough endoplasmic reticulum, changes in RNA metabolism and in the structure of the endoplasmic reticulum seem likely to be associated with alterations of plasma protein synthesis. Experimental alteration or prevention of any hepatotoxic effects of ethanol on RNA metabolism, on the structure of the endoplasmic reticulum, and on the synthesis plasma proteins may suggest means of treating or preventing ethanol-induced hepatic injury.