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G1- and G2-chalone effects of pig's stomach mucosa extract were registered in mice stomach gland epithelium. The inhibitory activity of chalones on cell's proliferation reduced following increased level of thyroid hormones. Local (chalones) and organism (thyroid hormones) factors cooperate in control of gland epithelial cell proliferation.

The control effects of thyroid hormones were registered in mice stomach gland epithelium. The growth fraction, rhythm, activity of proliferation changed differently in fundal and pyloric epithelium following increased level of thyroid hormones.

Electron microscopy with application of specific fluorescent histochemical reaction of Falck, as well as some methods of impregnation made it possible to indentify enterochromaffin cells in the stomach of hyperthyroid rats and the rats after cortisone injection under the conditions ox hyperfunction of the thyroid gland. After 20 days of L-thyroxin injection, and after 10 days of hydrocortisone injection, preceded by L-thyroxin, the amount of enterochromaffin cells in the epithelial layer of the gastric mucosa were noted to increase that was accompanied by simultaneous increase of the number of secretory argyrophil granules in their cytoplasm. Simultaneous injection of L-thyroxin and hydrocortisone, while not decreasing statistically significant amount of the cells, produced degradation of their cytoplasm.

Experiments on Wistar rats were made to examine serotonin metabolism in experimental thyrotoxicosis. Correlation analysis demonstrated a direct relationship between the number of detectable serotonin-producing cells and serotonin content in the gastric mucosa at early times of hyperthyroidism and a reverse one at later times.

Electron microscopy and cytochemical analysis have shown that protein-synthesizing apparatus of major stomach cells was characterized by the most pronounced changes observed in cell structures. Comparison between ultrastructural and biochemical analysis demonstrating leucine and orotic acid incorporation into the total protein and RNA, respectively, has revealed the correlation between the structure of nucleus, nucleolia and biosynthesizing activity of secretory cells. It was established that, while in parietal cells the enzymes at the organella level affected mainly mitochondria, in major cells protein-synthesizing apparatus was involved.

Electron histochemical investigation of the rat gastric mucous membrane has demonstrated that an abundant amount of thyroxine administered increases adenylate cyclase (AC) activity in the basal part of plasmolemma of parietal glandulocytes. As a result of the increased AC activity, the level of cyclic adenosine monophosphate cyclic guanylate monophosphate (c GMPh) level decrease. Ultrastructural and biochemical analyses have demonstrated that when hydrocortison is administered on the background of hyperthyroidism, localization of AC and GC activity in glandulocytes, as well as c AMPh and c GMPh contents change towards opposite direction comparing to the case when thyroxine alone is administered.

Alpha-tocopherol has been shown to cause less marked structural and metabolic changes in parietal stomach cells of hyperthyroid rats.

In experimentally hyperthyroid rats an increased amount of gastrin-producing (G) and histamine-producing (ECl) cells was noted by means of immunofluorescent biochemical methods and electron microscopically. Increased amount of the ECl cells was combined with a rise in histamine contents in the gastric mucosa. Hydrocortisone injections resulted in degranulation of the G- and ECl-cells. After hydrocortisone injection, the amount of histamine decreased more than two-fold. It was demonstrated that not only parietal glandulocytes, but also the gastric endocrine cells participated in disorders of a complex acid-producing mechanism.

Bilateral subdiaphragmal vagotomy was performed in sexually-mature Wistar male rats. To prevent neurodystrophic processes in the stomach mucous membrane some animals were injected pantetine subcutaneously at a dose of 30 mg/kg 5 times daily for 10 days. Pantetine injected to vagotomized animals decreased destructive lesions in the stomach mucous membrane. Enhanced biosynthesis and the inhibition of gastrin and serotonin release from G and Ec cells respectively have been observed. The results obtained substantiate the use of pantetine for the pharmacological correction of postoperative complications in patients after vagotomy.

In 212 male rats (200-250 g) ultrastructure of gastric parietal glandulocytes has been studied at various levels of the thyroid hormones in the organism. At experimentally produced hyperthyrosis a definite direct dependence has been noted to exist between the developmental stage of mitochondrial membranes (cristae), mitochondrial enzymes activity and the level of hydrochloride acid secretion. At hypothyrosis, the gastric parietal cells have signs of low differentiation--large number of cisterns in the granular cytoplasmic network and lack of tubulovesicles are noted.

Structural-metabolic changes of the principle cells in the rat gastric glands have been studied electron-microscopically and cytochemically with subsequent cytophotometry during the process of a disturbed pepsin secretion when thyroxin and hydrocortisone are administered. At the experimentally induced hypo- and hyperthyreosis, the gastric juice proteolytic activity is inhibited owing to a decreased energy potential of the principle cell. As ultrastructural analysis has demonstrated, under the conditions mentioned above not only zymogen transport is disturbed, but the release of the mature secretion is also inhibited. Secretory cycle of the principle cell is changed under the effect of hydrocortisone.

Experiments on rats with the use of ultrastructural analysis and fluorescent-histochemical and biochemical methods have shown serotonin to participate in the mechanism of the cytoprotective effect of polyglucin on the stomach. In the presence of experimental hyperthyrosis, intravenous injection of polyglucin coupled with hydrocortisone reduces the percentage of gastric mucosa lesions. This is a consequence of the restriction of serotonin release from serotonin-producing gastric cells.

Gastric secretory granulocytes in Wistar rats were studied electron microscopically and microspectrophotometrically. Injection of L-thyroxin for 10--30 days resulted in decrease of acid phosphatase and ATPh-ase activity in the main and parietal granulocytes. Injection of hydrocortisone after or simultaneously with saturation of the organism with L-thyroxin results in increasing acid phosphatase activity of these cells. After simultaneous prolonged injection of these two hormones, the number of lysosomes increased in parietal glandulocytes and mitochondrial membranes were destroyed in the main and parietal glandulocytes. Together with these phenomena, changes in the activity of oxidative-reductive enzymes were observed, demonstrating a sharp decrease of energetic importance of the main oxidation way in Krebs cycle.

Histochemical and electron microscopy identification revealed five types of endocrine cells (A-like, ECL, G, D, EC) in the gastric fundal and pyloric mucosa. Quantitative positive correlation was found between the revealed ECL, G cells and HCl secretion after the 10-day L-thyroxin administration. The correlation became negative after a longer administration. The ultrastructural changes of A-like ECL and G-cells (L-thyroxin for 10 days) proved their increased functional activity. After a longer period of L-thyroxin administration the ultrastructural characteristics of EC, D-cells suggested their degranulation. The majority of A-like, ECL and G-cells existed in the storing phase due to blocking of the extrusion phase.

Experiments on 48 Wistar rats evidence that in early times of hyperthyroidism, the action of thyroxine on parietal cells is mediated by histamine and cAMP, while in prolonged hyperthyroidism, its action on parietal cells refractory to endogenous histamine and cAMP is found to be unmediated and direct.