[Prostaglandin E2 binding by gastric mucosa cells in the rat]. / Sviazyvanie prostaglandina E2 kletkami slizistoi obolochki zheludka u krys.

After incubation of gastric pieces with [3H] prostaglandin E2 (PGE2) the label is accumulating predominantly over the cells situating in the middle third of the gastric glands proper, where mucus-secreting cells are mainly situated. As demonstrate biochemical experiments, [3H] PGE2 combines 5.5 times as intensively with the isolated cells fraction, which consists mainly of mucocytes but not of parietal cells. A suggestion is made that prostaglandin E2 contributes to biosynthesis and mucus secretion in the stomach when it immediately combines with mucocytes.

[Biochemical mechanisms of the regulation of gastric mucus secretion in the rat: the role of prostaglandin E2 and histamine]. / Biokhimicheskie mekhanizmy reguliatsii vydeleniia zheludochnoi slizi u krys: rol' prostaglandina E2 i gistamina.

Both prostaglandin E2 (PGE2) and histamine activated the adenylate cyclase system of rat gastric cells. Parietal acid-producing cells of the stomach were the target-cells for histamine, while PGE2 affected the mucous cells of gastric glands. The stimulating effect of PGE2 on mucus production occurred due to activation of protein synthesis. Electron microscopy of mucous cells detected alterations in structure of cells involved in biosynthesis of mucoids. Histamine appears to cause its effect on secretion of gastric mucus via the activating influence on production of hydrochloric acid.

Biochemical cascade mediating the estradiol action.

The data suggest that estradiol enhances the formation of histamine in rat uterus by induction of histidine decarboxylase; histamine activates adenylate cyclase providing accumulation of cyclic 3',5'-AMP, which, probably, induces glycolytic enzymes via phosphorylation of chromatin proteins, and mediates other estradiol effects. The chain of successively acting enzymes and mediators constitutes, obviously, a cascade amplifying the estradiol action. Since histamine is known to act as an intercellular mediator, attempts were made to find out the distribution of estradiol, histamine, and cyclic 3',5'-AMP among uterine cells. Autoradiography has shown that 3H-estradiol is bound by the nuclei of myometrium cells, 3H-histamine was found in the cytoplasm of these cells, 3H-cyclic 3',5'-AMP is selectively bound by the cells of capillary endothelium of the uterus. The estradiol mediators seem to spread their effect on different types of cells which form together a kind of a multicellular functional system.

Multistage functional system amplifying and spreading the effect of estradiol in rat uterus.

Estradiol is demonstrated to induce histidine decarboxylase, and histamine is shown to activate adenylate cyclase in rat uterus. Histamine and cyclic 3',5'-AMP mimic the effects of estradiol in that they enhance RNA synthesis, induce glycolytic enzymes and uterus imbibition. The data suggest that estradiol enhances by induction of histidine decarboxylase the formation of histamine, the latter activates adenylate cyclase providing accumulation of cyclic 3',5'-AMP, which, probably, induces glycolytic enzymes through phosphorylation of chromatin proteins, and mediates other estradiol effects. The chain of successively acting enzymes and mediators constitutes, obviously, a cascade amplifying estradiol action. Since histamine is known to act as an intercellular mediator, attempts were made to find out the distribution of estradiol histamine and cyclic 3',5'-AMP among uterus cells. Autoradiography has shown that [3H]-estradiol is bound by the nuclei of myometrium cells, [3H]-histamine was found above the cytoplasm of these cells, E13H]-cyclic 3',5'-AMP is selectively bound by the cells of capillary endothelium of the uterus. The estradiol mediators seem to spread effect of hormone on cells of different types which form together a kind of multicellular functional system.

[Radioautographic study of the localization of 3H-estradiol, 3H-histamine, and 3H-cyclic adenosine monophosphate in rat uterus]. / Radioavtograficheskoe issledovanie lokalizatsii 3H-estradiola, 3H-gistamina i 3H-tsiklicheskogo adenozinmonofosfata v matke u krys.

The method of radioautography has demonstrated that 3H-estradiol adheres to the nuclei of some myometrium cells, 3H-histamine is accepted by the cytoplasm of the majority of the myometrium cells, 3H-cyclic-AMP is selectively bound by the endothelial cells of capillaries and small vessels in all layers of the uterus. From the data obtained it is possible to conclude that estradiol and its mediators, histamine and cyclic-AMP, specifically interact with different cells and with different cell structures.

[Multiphasic regulatory system mediating the effect of estradiol in rat uterus]. / Mnogostupenchataia reguliatornaia sistema, oposreduiushchaia deistvie estradiola v matke krys.

Estradiol is shown to induce histidine decarboxylase and histamine to activate adenylate cyclase in the rat uterus. Cyclic AMP like histamine simulates the effect of estradiol, intensifying RNA synthesis and inducing glycolytic enzymes and uterus inhibition. It was found by autoradiography that 3H-estradiol is accepted by the nuclei of some myometrium cells, 3H-histamine by their cytoplasm and 3H-cAMP is selectively bound by endothelium cells of the uterus capillaries. The estradiol messengers (histamine and cAMP) seem to mediate hormonal effect of some uterus heterofunctional cells forming a kind of multicellular functional system.

Integration of biochemical functions of different cells of rat gastric mucosa for hydrochloric acid secretion.

The regulation patterns of gastric acid secretion in rats were investigated. Pentagastrin and histamine stimulate gastric acid secretion, but the inhibitors of DNA-dependent synthesis of RNA and of proteins prevent only the pentagastrin action. It has been found that pentagastrin induces histidine decarboxylase in gastric mucosa, ensuring local accumulation of histamine. The latter activates adenylate cyclase and results in 3',5'-AMP accumulation in gastric tissues. The administration of pentagastrin, histamine or 3',5'-AMP enhances the activity of gastric carbonic anhydrase, the enzyme which takes part in HCl formation. The data suggest that these three compounds act sequentially (pentagastrin leads to histamine leads to3',5'-AMP) and the effect of the last one could be mediated through 3',5'-AMP dependent protein kinase. The experiments in vitro demonstrated that gastric carbonic anhydrase can be separated into two isoenzymes and thephosphorylation of one of them by the 3',5'-AMP dependent protein kinase sharply increases its activity. The findings raise the possibility that histamine and 3',5'-AMP, mediating gastrin action, form together with enzymes (histidine decarboxylase, adenylate cyclase, protein kinase, carbonic anhydrase) a caascade of amplifiers. Autoradiographic studies have shown that [3H]-pentagastrin is not bound by oxyntic cells but adheres preferentially to histamine-producing alpha-like endocrine cells and to the chief cells, while 3H-histamine adheres preferentially to oxyntic and to chief cells. Electron microscopy indicates that only pentagastrin (but not histamine) initiates in alpha-like endocrine cells ultrastructural changes characteristic for induction. Pentagastrin, histamine and 3',5'-AMP administration produces in oxyntic cells ultrastructural changes typical for the secretion processes. These results lead to assumption that pentagastrin (gastrin) induces histidine decarboxylase in alpha-like endocrine cells of gastric glands. Histamine which is secreted enhances adenylate cyclase activity in the neighbouring oxyntic cells where 3',5'-AMP dependent protein kinase activates carbonic anhydrase by means of phosphorylation. These different cells form, probably, a multicellular functional unit for gastric acid secretion.

[Histochemical study of carbonic anhydrase and HCO3(-)-stimulated adenosine triphosphatase in the rat stomach during hydrochloric acid secretion]. / Gistokhimicheskoe issledovanie karboangidrazy i HCO3(-)-stimuliruemoi adenozintrifosfatazy v zheludke krys pri sekretsii solianoi kisloty

By means of histochemical methods it was established that carboanhydrase of the parietal cells of fundal glands and HCO-3 stimulated ATP-ase of the rat's gastric mucosa capillaries disposed next to the parietal cells were activated by food and histamine. The obtained data confirm the idea of the multicellular functional essembly sustaining HCL secretion (R. I. Salganik, 1974). Should gastrin induce the formation of histamine in endocrinous cells and the histamine activate carboanhydrase in parietal cells, our data confirm the supposition that HCO-3-ions stimulate ATP-ase sustaining the exchange between HCO-3-cells and C1- of blood to form HCl in the endothelial cells of blood capillaries adjacent to the parietal cells.