Female rats received quinoxaline, 2,3-dimethyl quinoxaline, 2,3-diphenyl quinoxaline and 2,3-dithiol quinoxaline by oral intubation for 4 days (500 mg/kg/day) and drug-metabolizing enzymes were investigated. A significant stimulation in liver microsomal enzymes occurred after 2,3-dimethyl quinoxaline and 2,3-diphenyl quinoxaline treatments; these changes were associated with increases in cytochrome P-450 level and in RNA and protein contents of the microsomal fraction. Quinoxaline had no effect on the metabolic rate of the studied substrates but increased the cytochrome P-450 and the RNA and protein levels; whereas, 2,3-dithiol quinoxaline inhibited the aminopyrine and N-methylaniline N-demethylations and decreased the cytochrome P-450 per mg microsomal protein.

Animals↗

PubMed1975

[Relations between the changes of the phagocytic activity of the reticuloendothelial system and the alterations in protein and nucleic acids contents of the rat liver (author's transl)].

The phagocytic activity of the reticuloendothelial system (RES) was evaluated after a single oral administration of soya-bean oil to male rats (15 g/kg). 1. An emulsion of soya-bean oil administered to the rat by gastric intubation activated the phagocytosis of colloidal carbon; the stimulation appeared on the 2nd day after treatment and persisted up to the 3rd day. There was also a relation between the stimulation of RES activity, under our experimental conditions, and the increased level observed in the protein and nucleic acid contents of the liver. 2. In contrast, without emulsion, soya-bean oil depressed the phagocytic activity on the 2nd and 3rd days after administration of the oil. These changes were associated with a diminution in ribonucleic acid and protein contents of the liver. Although the mechanisms of soya-bean oil-induced alterations of phagocytic activity were not clarified, there was a relationship between the RES stimulation or inhibition and the modifications in nucleic acid and protein contents of rat liver.

Animals↗

PubMed1975

[Effect of the quality of various vegetable oil emulsions on phagocytotic activity of the reticuloendothelial system in the rat].

In the liver, reticuloendothelial cells make up 35 p. 100 of the total cellular population. The characterization of the reticuloendothelial system (RES) is its phagocytic activity. Certain fatty acids and lipids produce stimulation or depression of phagocytic function. In the present study, the phagocytic activity of the RES has been evaluated 3 days after oral (15 g/kg) and intravenous (1, 5 g/kg) treatments of male rats with emulsions of peanut, canbra, soyabean, olive and rapeseed oils. The distribution of particle sizes of all suspensions were made microscopically. Phagocytic function was measured by the blood clearance of colloidal carbon injected intravenously; the phagocytic index was calculated from the formula: log C=Kt + log C0 where C and C0 were carbon concentrations in standard volumes of blood removed from the animals at times t and t0 (in minutes). Intravenous administrations with the 5 oil emulsions significantly increased the phagocytic function of the RES. However, with oral administration, stimulation or depression of phagocytic function were dependent of many factors, among them the nature of the oil and the physical and chemical structure of the lipid emulsion. The variations in particle sizes found in emulsions make it extremely difficult to draw any comparison between their effects on the RES phagocytic capacity of rat; but difference in the distribution of various particle sizes provided an indirect approach to studying their influences on RES stimulation or inhibition. However, it is obvious that although modifications of particle sizes may alter the level of phagocytic activity induced by certain oil emulsions, they do not explain the phenomenon. The activity of phagocytic function of oil emulsions on RES cells can be related to their physical or chemical properties; the mode of esterification of the fatty acids may be an important factor. However, no evidence has been obtained which in any way correlates changes in physical or chemical properties of the studied oil emulsions with the observed differences in effects upon the RES cells. No adequate explanation of the role of these parameters in the stimulation or inhibition of phagocytic properties of RES can be made and other studies are necessary.

Administration, Oral↗

PubMed1974