Effect of nicotinamide on hepatic microsomal drug metabolising system in tumour-bearing rats and mice.

Administration of nicotinamide to Wistar rats (100 mg/kg body wt.) bearing Yoshida sarcoma (ascites) tumour as well as to Swiss and CBA mice (250 mg/kg body wt.) bearing the transplantable fibrosarcoma and the spontaneously induced mammary carcinoma, respectively, was shown to bring about a reversal of the decreased activity of NADPH-cytochrome c reductase in host livers of the tumour-bearing animals.

Nicotinamide-induced hepatic microsomal mixed function oxidase system in rats.

A single intraperitoneal injection of nicotinamide (100 mg/kg body wt.), an endogenous non-toxic metabolite, to male rats was shown to significantly induce all the components of the hepatic microsomal mixed function oxidase system such as NADPH-cytochrome c reductase, cytochrome P-450 and cytochrome b5 as well as activities of drug-metabolizing enzymes such as arylhydrocarbon hydroxylase, aminopyrine demethylase and UDPglucuronosyltransferase. Tryptophan (1000 mg/kg body wt.

The association in vitro of polyribosomes with ribonuclease-treated derivatives of hepatic rough endoplasmic reticulum. Characteristics of the membrane binding sites and factors influencing association.

1. Pancreatic ribonuclease in dilute EDTA has been shown to condition rough-microsomal membranes from adult rat liver to accept exogenously added rat liver polyribosomes in vitro at 0-4 degrees C. Treated smooth membranes would not significantly interact with polyribosomes.

Cytoplasmic changes during thioacetamide induced hepatocarcinogenesis in rats.

Cytoplasmic changes were investigated in livers of rats at various intervals up to 50 weeks during primary induction of hepatoma by thioacetamide feeding.Microsomal Glucose-6-phosphatase and ATPase activities were shown to decrease progressively with increased period of thioacetamide feeding the fall in activities being more pronounced during the first 15 weeks.Hormonal induction of tryptophan pyrrolase and tyrosine transaminase activities was shown to undergo a significant decrease of 65% and 55% respectively at the end of 50 weeks feeding.