James B. Ragland

Hepatic triglyceride lipase deficiency in liver disease

The activity of post-heparin lipases in patients with alcoholic hepatitis and viral hepatitis was evaluated. Lipoprotein lipase and hepatic triglyceride lipase were differentiated by assay under high and low salt conditions and also by separation on heparin-agarose affinity chromatography columns. The mean activity of hepatic triglyceride lipase in the sera of liver disease patients was only 21–24% of the mean of controls, but lipoprotein lipase in patients’ sera was not different from normal levels. Hepatic triglyceride lipase deficiency may partially account for the accumulation of a triglyceride-rich low density lipoprotein in liver disease.

Multiplicity of mitochondrial monoamine oxidases

Abstract There have been only two brief reports which presented direct evidence of the existence of more than one monoamine oxidase in mitochondria although this has been suggested by many workers. Gorkin (1963) partially separated p-nitrophenylethylamine oxidase activity from m-nitro-p-hydroxybenzylamine oxidase activity by ion exchange chromatography of mitochondrial extracts in the presence of nonionic detergent (OP-10). Youdim and Sandler (1967) report the appearance of two or three bands of enzyme activity upon polyacrylamide gel electrophoresis of partially purified monoamine oxidase from rat liver or human placental mitochondria. This paper describes the separation of solubilized liver mitochondrial monoamine oxidases from three species by gel filtration in the presence of detergent. Based on substrate specificity there appear to be at least three different monoamine oxidases present in rat and rabbit liver and at least two in beef liver.

The Role of Lecithin:Cholesterol Acyltransferase Deficiency in the Apoprotein Metabolism of Alcoholic Hepatitis

In alcoholic hepatitis a severe but reversible LCAT deficiency provides a model to investigate the role of LCAT in lipoprotein metabolism. Serial changes in the lipid and apoprotein composition of the plasma lipoproteins were investigated throughout the illness of patients with alcoholic hepatitis. In severe alcoholic hepatitis, LCAT and cholesteryl esters were greatly reduced or undetectable in plasma. Lipoproteins were isolated by sequential ultracentrifugation of fasting plasma. VLDL was normal in triglyceride and phospholipid content but deficient in cholesteryl esters. Polyacrylamide gel electrophoresis of this fraction revealed greatly increased apo B (≈97%) as tetra-methylurea insoluble protein with traces of apo C and apo E, a composition compatible with nascent VLDL of hepatic origin. LDL was rich in triglyceride but deficient in cholesteryl esters. HDL was enriched in phospholipid but deficient in cholesteryl esters. Polyacrylamide gel electrophoresis demonstrated only apo B in LDL. The predomin...

Quantitative, multicomponent analysis of fatty acids from cholesteryl esters by chemical ionization reconstructed mass chromatography

Reconstructed mass chromatography using methane as a carrier and reagent gas for chemical ionization gas chromatography-mass spectrometry of the derived methyl esters allows rapid, quantitative microdeterminations of complete cholesteryl ester fatty acid profiles. The sensitivity of this method is consistent with completely specific, multicomponent assay at the picomole level. Introduction of two homologues as internal standards, one into the intact biological specimen and the other after derivatization, provides a measure of the net efficiency of the processes of extraction and derivatization. This procedure may be extended readily to the determination of fatty acid profiles in most biological fluids.

d-Galactosamine hepatotoxicity: V. Role of free fatty acids in the pathogenesis of fatty liver

Abstract The role of free fatty acids (FFA) in the pathogenesis of fatty liver was investigated in female rats who received a single ip injection of d -galactosamine-HCl, (GalN), 750 mg/kg body weight. Groups of rats were either fasted for 14 hr prior to GalN injection and then fasted for the duration of the experiment or were fed ad libitum prior to and after GalN administration. Plasma FFA were determined in groups of fasting or fed rats sacrificed at intervals between 0 and 24 hr after GalN administration. The results revealed a progressive increase in plasma FFA in GalN-injected fasted rats (0 hr, 0.40 μmol/ml; 24 hr, 1.09 μmol/ml) whereas in fed animals only a modest increase in plasma FFA concentrations occurred. Hepatic triglyceride content was determined in groups of fasted and fed rats at 6 and 24 hr after GalN administration. Hepatic triglycerides, in fasted rats, were increased 7-fold at 6 hr (22.4 ± 8.5 mg/g) and were markedly increased at 24 hr (114.8 ± 18.4 mg/g). In contrast, feeding protected the rats from the development of fatty liver since hepatic triglycerides were only twice controls at 6 hr and 4-fold increased 24 hr after GalN. Ultrastructural studies were performed at 15, 24, and 48 hr after GalN in fed and fasted rats. Electron microscopy disclosed hepatocellular necrosis and profound fat accumulation in the fasted animals; however, feeding afforded marked protection against the development of fatty liver and hepatic injury. The results of these studies indicate that the GalN-induced fatty liver is associated with a sustained elevation of plasma FFA. The increase in plasma FFA can be prevented by feeding the animals prior to and after GalN administration suggesting that a stimulus for FFA elevation may be the alterations in carbohydrate metabolism known to be induced by GalN in rat liver.