stituent of marijuana, Cannabis sativa L. It is well known that THC is oxidized to a number of metabolites in the liver of mammals. Recent studies have clarified that P450 plays a major role in the oxidation of THC. We have previously reported that a hepatic microsomal enzyme, named microsomal alcohol oxygenase (MALCO), is able to oxidize 7aand 7b-hydroxy-D-THC to 7-oxo-D-THC in the presence of...

The activity of microsomal 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) [mevalonate:NADP+ oxidoreductase (CoA-acylating); EC 1.1.1.34] was inhibited by ATP+Mg2+. Inactivation of HMG-CoA reductase by ATP+Mg2+ was dependent on time, temperature, and ATP concentration. Incubation of microsomal HMG-CoA reductase with [gamma-32P]ATP+Mg2+ was associated with a reciprocal increa...

Because the onset of triacylglycerol-rich lipoprotein synthesis occurs in guinea pig liver during fetal life, we investigated the microsomal enzyme activities of triacylglycerol synthesis in fetal and postnatal guinea pig liver. Hepatic monoacylglycerol acyltransferase specific and total microsomal activities peaked by the 50th day of gestation and declined rapidly after birth to levels that we...

In cells of Saccharomyces cerevisiae grown with glucose in standing cultures, the microsomal fraction had the highest specific activity for acetyl-coenzyme A synthetase and contained the greatest fraction of the total activity regardless of when the cells were harvested during growth. The addition of acetate did not affect the distribution of the enzyme, nor did subsequent aeration of such cell...

The relation between precursors and restoration of A-form MAO activity in rat liver after administration of clorgyline to rats was investigated by measuring the rates of recovery of A-form MAO activity after treatment with the inhibitor. The half-lives of mitochondrial and microsomal A-form MAO were estimated as 3.5 and 2.0 days, respectively. MAO activity and the amount of MAO molecules were c...

A study of the activation of several long chain saturated and unsaturated fatty acids by rat liver preparations was undertaken. Investigation of reaction requirements and appropriate modifications revealed that rat liver is extremely active in long chain acyl-coenzyme A synthetase or synthetases (acid: CoA ligase (AMP), EC 6.2.1.3) activity. With pahnitate as substrate, the cell membrane fracti...

The hepatic effects of phthalate esters and related compounds on peroxisomal and microsomal enzyme activities were investigated in the intact animal and in primary hepatocyte cultures. In vitro studies with a series of phthalate monoesters demonstrated structure activity differences in the induction of the specific peroxisomal marker KCN-insensitive palmitoyl-CoA oxidation and also of carnitine...

Biological Responses of the Rat to Polychlorinated Biphenyls. BRUCKNER, J. V., KHANNA, K. L. and CORNISH, H. H. (1973). Toxicol. Appl. Pharmacol. 24, 434-448. A commercial polychlorinated biphenyl mixture (PCBs), Aroclor 1242, was administered to rats po by intubation in order to determine toxic manifestations of acute and subacute ingestion. In addition, the effect of PCBs on hepatic microsoma...

Aerobic incubation of 7-dehydrocholesterol with mouse liver microsomes in the presence of a detergent, an iron salt, and NADH or NADPH resulted in the conversion of the sterol to more polar products. In the presence of Fe(3+) or low levels of Fe(2+) the reaction was dependent upon reduced pyridine nucleotide and a microsomal enzyme system. At high levels of Fe(2+) or in the presence of Fe(2+) o...

Gluconeogenesis and glycogenolysis are essential hepatic functions required for glucose homeostasis. During the initial phase of hepatic regeneration, the immediate-early genes (IEG) are rapidly expressed, and the IEG RL-1 encodes for glucose-6-phosphatase (G-6- Pase). G-6- Pase is a microsomal enzyme essential for gluconeogenesis and glycogenolysis. This study employs a partial-hepatectomy mod...