[Seasonal changes in the functional state of the liver mitochondria in different animals].

A difference in velocity of oxydation of the ATP substrates synthesis, conjugation and efficacy of oxydation of phosphorylation in animals with different functional systemic state, and seasonal differences in these processes, were found in different animals.

[The spatial distribution of mitochondrial respiration and oxidative phosphorylation along the small intestine in rats of different ages].

Growing rats were shown to have the maximum of respiratory and ATP-synthetase activities in the duodenum and proximal part of the small intestine, the minimum--in its distal part, whereas the medial part of the intestinal tube was in intermediate position. These parameters were equally distributed along the small intestine in adult rats. In old rats, the highest rate of oxygen consumption was revealed in the mitochondria of the medial part, the lower one--in the proximal part, and the lowest level was found in the duodenum and in distal part of the small intestine.

[The enzyme-transport characteristics of the small intestine of rats during aging].

Ageing was shown to be accompanied by changes of the activity levels of the small intestine's carbohydrases, dipeptidases, and alkaline phosphatases. The changes occurred both under normal conditions and after operations on the small intestine. In ageing, the small intestine's capacity for the homeomorphosis decreases irrespective of either increase or decrease in the functional loading.

[The isolation of mitochondria fron different sections of the small intestine and their functional characteristics].

High level of oxygen consumption is specific for the proximal part of small intestine in rats, particularly when mitochondria are active and when oxidative phosphorylation is uncoupled by 2.4 Dinitrophenol. High degree of coupling seems to exist in this part of the intestine.

A revision of current data and views on membrane hydrolysis and transport in the mammalian small intestine based on a comparison of techniques of chronic and acute experiments: experimental re-investigation and critical review.

Literature data and the results of our investigations using both generally accepted and original perfusion techniques of the isolated loop of the rat small intestine in in vivo experiments are reviewed. Significant differences in the functioning of the small intestine under conditions of acute and chronic experiments are revealed. It has been established that in chronic experiments as compared to acute ones: (a) the absorption of glucose, galactose, fructose and glycine is 2-5 times higher; (b) Kt as well as Jmax values of the transport of these nutrients differ considerably; (c) Na+-independent mechanism of glucose and glycine transport predominates; (d) higher rates of membrane hydrolysis and more effective interactions between enzyme and transport systems of the enterocyte brush border membranes are observed; (e) functional characteristics of the small intestine affected by various experimental factors are more stable.

Membrane digestion and transport under physiological conditions: a review of available data.

A technique to study membrane digestion and transport in the small intestine under physiological conditions has been developed. The technique is based on a continuous perfusion of a chronically isolated loop of the rat small intestine. Membrane hydrolysis and transport of some nutrients in the rat small intestine in chronic, as well as in acute (in situ) experiments was investigated.

[Changes in carbohydrate digestion enzymes and liver glycogen during heat adaptation].

Adult white rats were exposed daily during 30 days to 2-hour heating (40--41 degrees)--adaptation, and then were transferred to ordinary temperature conditions at 25--27 degrees--desadaptation. The initial period of adaptation revealed a decrease of the liver glycogen content and a relatively constant level of glycemia. A considerable activation of the carbohydrate digestion enzyme systems followed this lowering of energy resources.

[Effect of alloxan diabetes on the enzyme activity of the mucous membrane of the small intestine].

Experiments on male rats showed that following subcutaneous injection of alloxan in a dose of 15 mg per 100 g of body weight amylolytic, invertase, glycyl-l-tyrosine dipeptidehydrolase activity of the mucosa of the small intestine altered differently. As a result, there occurred a deviation of the enzymatic spectrum from the normal characterized by a sharp increase (with the development of diabetes) of the activity of the carbohydrate hydrolysing enzymes (amylase and invertase) with a simultaneous reduction of the activity of the enzymes participating in protein (dipeptidase) and fat (monglyceridlipase) hydrolysis.