[Response of glycine and glycyl-L-valine uptake parametrs across in vitro everted sacs of chicken gut to variations in oxygenation rate and fasting].

Energy-dependent accumulation of glycine and glycyl-L-valine within the small intestinal mucosa in a chicken model of in vitro local oxygenation of the small intestinal preparation was studied. It has been shown that the most effective bilateral oxygenation significantly increase accumulation of glycyl-L-valine in the proximal segment as compared to that under oxygenation only from serosal surface both in the fed and 24-hour fasted chickens, whereas in other segments these differences was less apparent. This may be due to increased H+/ peptide cotransporter expression in the proximal segment.

[Effects of natural (zinc, vitamin E) and synthetic (diludin) antioxidants on the intestinal permeability in chicks with vitamin A deficiency].

The main concern of this work was to examine the relation between altered antioxidant status on the one hand and increase in L-tryptophan absorption in the small intestine in order to bring further information regarding to possible role of vitamin A and zinc to maintaining of intestinal epithelial barrier integrity, on the other hand. In control, only some ideal tight junctions at the tip of the villi were permeable to ZnC1(2), whereas in A-hypovitaminosis permeability increased significantly. Studies demonstrate that an increased L-tryptophan accumulation in the intestinal mucous may result from a free radical damage to the mucous surface with formation of "leaky" junctions in the ilea.

[The role of zinc in the iliac absorption of various L-tryptophane forms in chickens].

Zinc was found to enhance absorption of free and "peptide" L-tryptophan across the chick mucosal brush border. Intestinal absorption of free L-tryptophan can be partially inhibited by excessive amount of zinc. The findings suggest that zinc interacts with free and "peptide" L-tryptophan transports protecting them against degradation.

[Alternative paths of zinc transepithelial transport in the small intestine].

Interrelations among changes in 11-oxycorticosteroids (11-OSC) in blood plasma, catecholamines (CA), and acetylcholinesterase (AChE) activity in nerve fibres of the thymus, as well as qualitative content and proliferative capacity of thymic and blood cells under the effect of the rat recombinant interleukin-1 beta (IL-1 beta) normally and under conditions of hypothalamic-pituitary-adrenocortical depression, were studied. The changes were the most obvious within 15 and 120 min following the IL-1 beta administration: elevation of the 11-OSC, increase in the CA content, and decrease in the AChE activity in thymic nerve fibres. Preliminary administration of dexamethasone prevented the effects.

[The characteristics of amino acid transport in the small intestine of chicks with avitaminosis A].

An increased amino acid absorption occurred early in chicks in the vitamin A deficiency. This data suggests an effect of the vitamin A upon differentiation of amino acid channels within apical membrane of the absorbing cells.

[Morphofunctional analysis of zinc-accumulating capacity of digestive system organs].

The distribution of zinc and related changes have been studied in zinc--loaded chick pancreas, ileum and liver at the ultrastructural level by sulphide--silver method. White Leghorn chicks fed a high zinc diets (50, 500, 1000, 2000 and 4000 mgZn/kg diet) for 6 weeks, were killed at intervals; portions of their organs were fixed for light and electron microscopy; other samples were analyzed for zinc by AA spectrophotometry. A drastic increase of zinc level in chick pancreas fed 2000 mg Zn/kg diet (as ZnCl2) was associated with acinar cell degeneration.

[Disorders of zinc transport through the ileal epithelium in vitamin A deficiency and ischemia].

By means of histochemical revealing of zinc and applying radioactive isotope 65Zn accumulation, absorption and distribution of cations of this metal in the mucous membrane of the iliac intestine have been studied in chicken, normal, at ischemia and at A-avitaminosis. An essential zinc-depositing ability is peculiar to coverings of mucus upon the intestine epithelium, and among intracellular components--to smooth endoplasmic reticulum. A-avitaminosis and especially ischemia result in increasing permeability of the apical part of the external membrane of epitheliocytes, in overloading of the latter with zinc cations, when they are introduced into the intestine, as well as in decreasing transepithelial transport of zinc.

[Absorption and localization of zinc in the ileum of chicks dependent on provision with vitamin A].

Vitamin A increase the accumulation and transport of zinc in the chick ileal mucosa. Regulating effect of this vitamin on the mentioned processes was already observed in the initial stage zinc uptake in the intestinal mucosa--its storage in the mucus layer. Stimulation of zinc absorption by vitamin A can be related to a specific carrier-vitamin A-dependent zinc-binding protein.

Vitamin-A-dependent zinc-binding protein and intestinal absorption of Zn in chicks.

It was demonstrated that the development of experimental avitaminosis A in chicks led to secondary zinc deficiency. The balance of Zn in the chick became negative, while the Zn content of various tissues decreased. Thus in vitamin-A-deficient chicks the serum Zn content was 1258 (SD 26.

[Plasma zinc content in patients with chronic renal insufficiency before and after kidney transplantation].

Zinc content in blood plasma was measured in patients with chronic renal failure (CRF) before and after kidney transplantation by atomic-absorption spectrophotometry. Plasma zinc was revealed to be lowered. However, routine intake of vitamin A by the patients led to an elevation in zinc content.

[Direct stimulatory action of blood serum, vitamin D3, and its hydroxy-analogs on calcium transport in the small intestine of chicks in vitro].

A study was made of the effect of blood serum, vitamin D3 and its hydroxy-analogs (25-hydroxyvitamin D4. 1 alpha-hydroxyvitamin D3) on Ca2+ transport across the wall of the noninverted small sac of D-avitaminosis chicken during incubation in vitro. It was shown that blood serum from chickens fed vitamin D3 in different doses (50--20 000 IU) and at varying time (1--72 h) before sacrifice produced a marked stimulating action on the cation transport 10 min after administration into the intestinal cavity as compared with the effect produced by the serum from D-avitaminosis chickens.

[Rapid biological method for assessing D-vitamin supply of chicks].

A segment of the small intestine of chicks turned inside out and pulled on a glass rod was placed into a buffer solution. The Ca2+ consumption from the solution was monitored, using the color murexide reaction. The Ca2+ binding during the first 5 min was much higher in the chicks well supplied with D-vitamin than in the D-vitamin deficient chicks.

[Stimulating effect of vitamin A on the absorption and metabolism of zinc in chicks].

Zinc metabolism and absorption were examined in chicks of two groups that differed in vitamin A supply. Five week chicks that were given a diet without an addition of vitamin A showed overt symptoms of A-avitaminosis. The condition was followed by marked changes in the zinc metabolism and absorption in the intestine and by insignificant changes in the calcium metabolism.