[Pinocytotic route of calcium transport through the intestinal epithelium in newborn rats]. / Pinotsitoznyi put' transporta kal'tsiia cherez kishechnyi épitelii u novorozhdennykh krysiat.

A comparative electron microscope study has been made on the localization of calcium in the epithelium of duodenum in chicks and rats during cation absorption. The main amount of calcium in animal epithelium concentrated in the brush border region and lateral membranes. In new-born rats, calcium is localized on the inner surface of pinocytic vesicles, which are moving from the apical surface through the area above the nucleus towards the lateral plasmatic membrane of enterocytes.

[Participation of the goblet cells of the small intestine in the excretion of Fe, Zn and Pb cations]. / Uchastie bokalovidnykh kletok tonkogo kishechnika v ékskretsii kationov Fe, Zn i Pb.

A comparative study of the excess of Zn, Fe and Pb on the amount of goblet cells (GC) and localization of these cations in the chick small intestine epithelium was carried out. In chicks with additional dose of Zn (2 g/kg) and Pb (0.2 g/kg), compared to control chicks the amount of GC in the epithelium of various intestinal parts increased by 1.5-1.8 times. Under a high dose of Pb (2.0 g/kg), the amount of GC increased by 3-4 times, and degenerative changes in the epithelium were observed. A histochemical electron microscopical study of duodenal sections revealed an accumulation of Fe, Zn and Pb within GC and in their excretion, in addition to brush border and glycocalyx. The involvement of intestinal GC in cation excretion is proven.

[Role of goblet enterocytes in the intestinal excretion of calcium]. / Rol' bokalovidnykh énterotsitov v kishechnoi ékskretsii kal'tsiia.

A comparative study on the amount of goblet cells and excretion of endogenic calcium in the small intestine of chicks has been made. The amount of goblet cells (per brush area unit) significantly increased at the deficiency of vitamin D3 as well as at the surplus of calcium in the diet. Excretion intensity of endogenic calcium (determined by 45Ca) correlates directly with the amount of goblet cells. Histochemical and electron microscopical investigations show that precipitate accumulations containing calcium are absorbed in goblet cells and their secret on the surface of the cells. The significance of goblet cells in the intestinal excretion of endogenic calcium is discussed.

[Vitamin D, calcium-binding protein and calcium absorption in the intestines]. / Vitamin D, kal'tsiisviazyvaiushchii belok i absorbtsiia kal'tsiia v kishechnike.

The author presents his own and literature data concerning the action of vitamin D and its analogs on the biosynthesis of calcium-binding protein (CaBP) in the chick intestinal mucosa. The mechanism of involvement of this protein in calcium transport across the intestinal epithelium is discussed. CaCP is considered as a specific test-substance for vitamin D. A close correlation between the CaCP content in the intestinal mucosa and the vitamin antirachitic effect is demonstrated. The quantitative estimates of the biological activity of various forms of vitamin D, their metabolites and synthetic analogs with respect to the CaCP content are given.

[Stimulating effect of vitamin A on the absorption and metabolism of zinc in chicks]. / Stimuliruiushchee deistvie vitamina A na obmen i vsasyvanie tsinka u tsypliat

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. Vitamin A was administered per os at a dose of 24,000 i. u. (in oil) and 72 hours later zinc absorption in the ileum increased noticeably and zinc balance in the body became positive.

[Comparative antirachitic activity of vitamins D2 and D3 in the body of chicks]. / Sravnitel'naia antirakhiticheskaia aktivnost' vitaminov D2 i D3 v organizme tsypliat.

In the four-week study the antirachitic action of vitamin D2 in different does (5000, 7500, 10 000 I. U. per kg food) and of vitamin D3 in a dose of 500 I. U. per kg food was investigated in chicks. The vitamin efficiency was measured with respect to the following seven parameters: weight gain, serum content of Ca and P, serum activity of alkaline phosphatase, bone ash content, content of Ca-binding protein in the duodenal mucosa, and weight of parathyroid glands. In regard to these parameters, vitamin D2 in a dose of 7500 I. U./kg and vitamin D3 in a dose of 500 I.U./kg produced a similar effect. Thus, the antirachitic effect of vitamin D3 was 15 times higher than that of vitamin D2. In the three-day study of the effect of vitamins D2 and D3 on the synthesis of Ca-binding protein it was found that they exerted a similar effect when the dose of vitamin D2 was 14.5 times higher than that of vitamin D3.

[Rapid biological method for assessing D-vitamin supply of chicks]. / Biologicheskii ekspress-metod otsenki D-vitaminnoi obespechennosti tyspliat.

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. The level of binding was determined by the content of specific calcium-binding protein in the intestinal mucosa. A close correlation between the dosage of D3-vitamin and the amount of Ca2+ consumed by the intestine from the solution and bound with the mucosa was established. These findings together with the simplicity of the procedure suggest that measurement of the calcium binding capacity of an intestinal segment can be used as a rapid method of assaying the D-vitamin status of the animal.

[Biological method of quantitating vitamin D in different preparations and diets]. / Biologicheskii metod kolichestvennogo opredeleniia bitamina D v razlichnykh preparatakh i kormakh.

A biological method for quantitative assay of vitamin D3 in various preparations has been developed. The method is based on a close correlation between the vitamin D3 dose and the content of calcium-binding protein in the duodenal mucosa of rachitic chickens 72 hrs after vitamin D3 administration. Calcium-binding protein is assayed by radial immunodiffusion in agar-agar. The calibration curve of the dose-protein dependence allows measurements of I to 500 IU of vitamin D3 in the sample tested. The method shows good accuracy and reproducibility. The paper presents the results of quantitation of vitamin D in various preparations.

[Evaluation of the vitamin D activity of yeasts with altered sterol metabolism]. / Otsenka D-vitaminnoi aktivnosti shtammov drozhzhei s izmenennym metabolizmom sterinov.

The sterol content of Saccharomyces strains with altered ergosterol metabolism was studied by UV-spectrophotometry, thin-layer chromatography and chromatographic mass-spectroscopy. A technique for estimation of D-vitamin activity of the yeast strains is proposed. The irradiated biomass of the strains accumulated ergosta-5,7-dien-3 beta-ol and also cholesta-5,7,24-trien-3 beta-ol and cholesta-5,7,22,24-tetraen-3 beta-ol is characterized by high antirachitic activity.

[1 alpha-hydroxyvitamin D3: chemical synthesis and biological effect]. / 1 alpha-oksivitamin D3: khimicheskii sintez i biologicheskoe deistvie.

A method for the synthesis of an analog of vitamin D3--1alpha-hydroxy vitamin D3 (1alpha-OH D3) from cholesta-4,6-dien-3beta-ol was developed. Biological activity of this compound in the chick organism was measured. The growth stimulating effect of 1alpha-OH D3 and its effect on bone tissue mineralization and serum biochemical parameters (content of calcium, inorganic phosphorus and activity of alkaline phosphatase) were 4--5 times higher than those of vitamin D3 in low doses (19.5--39 pmole/day). In chicks given 1alpha-OH D3 at doses of 39--195 pmole/day most biochemical parameters reached plateau typical of chicks adequately provided with vitamin D. A peculiar feature of 1alpha-OH D3 was a rapid response of the chick organism to/low doses. As early as one hour after intramuscular injection of 650 pmole of 1alpha-OH D3 to D-avitaminotic chicks, the content of calcium-bound protein in the intestinal mucosa and active transport of calcium ions in the inverted intestinal sac increased drastically. It was demonstrated that 1alpha-OH D3 showed antirachitic action, when the physiological reaction to vitamin D3 was inhibited by dietary strontium.