[Carbohydrate hydrolysis, transport and utilization during limited motor activity in rats]. / Gidroliz, transport i utilizatsiia uglevodov pri ogranichenii dvigatel'noi aktivnosti u krys.

Carbohydrate hydrolysis, transport and utilization were investigated in rats exposed to diminished motor activity for 90 days. Glycemic curves were examined using provocative tests with equivalent quantities (1.5 g/kg body weight) of poly-, oligo- and monosaccharides (starch, maltose, glucose). Simultaneously, carbohydrases were measured in the homogenates of the pancreas, duodenal mucosa and small intestine as well as radioimmune insulin and glucagon were determined in blood. In the course of hypokinesia carbohydrate hydrolysis, transport and utilization varied in a different manner. At the beginning of exposure the activity of carbohydrases responsible for carbohydrate hydrolysis in the cavity and membranes increased which was accompanied by hyperglycemia and rapid utilization of carbohydrates. This is associated with nonspecific reactions to hypokinesia and higher requirements of the body for the energy substrate. By hypokinesia day 30 carbohydrate hydrolysis and transport were inhibited, hypoglycemia developed but glucose utilization remained unchanged. At a later stage of exposure the system of carbohydrate hydrolysis and transport showed an adaptive reaction; inhibition of pancreatic amylase was accompanied by accelerated enzyme transport in the small intestine and glucose resorption. In this situation the glycemic curves became extended suggesting a delay in glucose utilization. The latter was induced by changes in the endocrine compartment of the pancreas.

[Digestive function of the small intestine and pancreas in rats on artificial feeding]. / Sostoianie pishchevaritel'noi funktsii tonkoi kishki i podzheludochnoi zhelezy krys v usloviiakh iskusstvennogo pitaniia.

Full-value diets of similar composition were given to male rats weighing 207-230 g, by intravenous (group 1) or intragastric (group 2) routes. The proportion of amino acids, fats and carbohydrates was 9.9:15.7:74.4 (with regard to their calorific value). The diet calorific value comprised 60.6 kcal/rat/day. An average mass increase in group 1 was 2.44 +/- 0.14 g/day, in group 2 - 1.75 +/- 0.11 g/day. The protein content and activities of alpha- and gamma-amylase, invertase, maltase, and glycil-L-leucine dipeptidase were assayed in the intestinal mucosa of the proximal portion of the small intestine in group 1 rats, while a decreased alpha-amylase activity in the distal portion of the small intestine was recorded in the animals of group 2. The mass of the pancreas in the rats of group 1 and 2 was authentically lower than in the control rats which received oral feeding with natural foods. The lowest mass of the pancreas was observed in the rats of group 1. Specific activity of trypsin, lipase and RNase in the pancreatic tissues of rats in groups 1 and 2 was similar. The results of the study have evidenced a lowered function of the digestive system under conditions of artificial feeding, especially in case of intravenous nutrition.

[Digestive system status after prolonged space flights]. / Sostoianie pishchevaritel'noi sistemy posle dlitel'nykh kosmicheskikh poletov.

In the crewmembers of four Salyut-6 long-term flights, enzyme excretory function of the gastro-intestinal tract was investigated. These studies included: gastric proenzyme, pepsinogen, and pancreatic enzymes, amylase and lipase, in blood and urine, trypsin in blood, intestinal enzymes, invertase and glycyl-L-leucine dipeptidase in feces, and lipids in feces. The results obtained demonstrated a correlation between changes in enzyme excretion and space flight duration and profile. After the 140- and 175-day flight the most marked changes in the digestive organs were seen; they manifested as a simultaneous increase in secretory function of the stomach and the pancreas. However, after the 185-day flight, in which advanced countermeasures were used, the above changes were less distinct.

[Functional state of the gastrointestinal tract organs in rats after a flight on the Kosmos-1129 biosatellite]. / Funktsional'noe sostoianie organov zheludochno-kishechnogo trakta posle poleta na biosputnike "Kosmos-1129".

The enzyme-excretory and motor functions of the gastrointestinal tract of rats flown for 18.5 days onboard the biosatellite Cosmos-1129 were studied. Immediately postflight, the pepsin synthesis decreased and the dipeptide parietal hydrolysis increased. At R + 6, the activity of the enzymes responsible for the cavitary and parietal hydrolysis of lipids significantly grew and that of the enzymes involved in protein hydrolysis fell. At R + 30, the carbohydrate hydrolysis was inhibited and the activity of lipolytic enzymes enhanced markedly. The amplitude and rhythm of stomach biopotentials were dysbalanced. The so-called immobilization stress of intact rats brought about activation of lipase, monoglyceridyl lipase, dipeptidase and inhibition of amylase and invertase. The immobilization exposure of flight rats caused inhibition of the membrane hydrolysis of proteins and carbohydrates and lack of the pancreatic reaction.