Content of prostaglandins and cyclic AMP in rat tissue

The content of prostaglandins (PG) and cyclic adenosine-3,5-monophosphate (cyclic AMP) in rat tissues was studied by a radioisotope method. The maximal content of both PG and cyclic AMP was found in the same organs, those functioning most actively: the brain, endocrine glands, and small intestine, and the minimal content in adipose tissue. The investigations show close functional interdependence between PG synthesis and adenylate cyclase activity in the tissues of the body.Kiev Scientific-Research Institute of Endocrinology and Metabolism. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 4, pp. 416–418, April, 1977.     

Effect of diquertin on platelet content of cyclic nucleotides

The effects of diquertin on the content of cyclic nucleotides in human platelets was studied. Diquertin in a concentration of 5 mM increased the content of cAMP and cGMP in native and thrombin-activated platelets probably due to inhibition of phosphodiesterase. Increasing the concentration of diquertin above 5 mM did not potentiate this effect. The antiaggregation effect of diquertin was probably associated with the increase in platelet levels of cyclic nucleotides. Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny,Vol. 128, No. 9, pp. 267–269, September, 1999     

Role of endoperoxides of the prostaglandins in platelet aggegation

Phospholipase A and lysolecithin stimulate the reaction of liberation of thromboplastic factor and aggregation of erythrocytes and platelets. Polarographic investigations have shown that these aggregating agents cause absorption of O₂ in medium containing platelets, possible evidence of the formation of these conditions of intermediate products of prostaglandin synthesis, namely endoperoxides. Albumin does not prevent the liberation reaction and the absorption of O₂ caused by phospholipase and lysolecithin but it completely inhibits their aggregating action. Aspirin, on the other hand, blocks O₂ consumption by platelets althoug its action on the aggregating effect of lysolecithin is only very slight. It is suggested that the aggregation of the blood cells is connected with perturbation of the lipid-protein structure of their membranes and not with endoperoxide synthesis.Gor'kii Research Institute of Traumatology and Orthopedics. (Presented by Academician of the Academy of Medical Sciences of the USSR V. S. Savel'ev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 7, pp. 13–16, July, 1977.     

Effect of cyclic AMP on cells of experimental lymphatic leukemia L-5718

The effect of cyclic AMP (cAMP), dibutyryl-cAMP, and theophylline (an inhibitor of phosphodiesterase, the enzyme converting adenosine-3, 5-monophosphate into adenosine-5-monophosphate) on the intensity of proliferation (as reflected in the increase in the nucleic acid content in the culture), DNA synthesis (thymidine-H³ incorporation), and transplantation properties (ability to repopulatein vivo) of leukemic cells of strain L-5178 was studied. The experiments showed that cAMP in a concentration of 0.8 mM inhibits thymidine-H³ incorporation considerably, retards proliferation, and reduces the transplantability of the leukemic cells. Theophylline and dibutyryl-cAMP have comparatively weak ability to inhibit DNA synthesis and the proliferative activity and transplantation properties of the cells.Laboratory of Biochemistry and Laboratory of Experimental Therapy of Leukemias, Central Institute of Hematology and Blood Transfusion, Ministry of Health of the USSR. Laboratory for the Search for New Antibiotics, All-Union Research Institute for the Search for New Antibiotics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR K. V. Bunin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 3, pp. 365–367, March, 1976.     

Role of E-type prostaglandins in tumor cells during contact with NK cellsin vitro

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 115, N ^o 2, pp. 193–194, February, 1993     

Arginine-vasopressin effect on the content of cyclic nucleotides, cellular protein phosphorylation, and adhesion to plastic of peritoneal mouse macrophages

Intracellular concentration of cAMP and phosphorylation of 15 kD protein in cultured mouse peritoneal macrophages are increased in the presence of arginine-vasopressin. Vasopressin, decreases adhesion of macrophages to plastic. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7 pp. 80–83, July 1998     

Effect of cyclic nucleotides and of isopropylnoradrenalin on the partial pressure and consumption of oxygen

Isopropylnoradrenalin, cyclic AMP, and dibutyryl-3,5-AMP (DB) lower the partial pressure of oxygen (pO₂) in the liver and spleen and increase the oxygen consumption of the body. The time course of these two effects for isopropylnoradrenalin and cyclic AMP correlates closely. The increase in heat production was not accompanied by any significant change in the respiratory quotient. The effects of cyclic AMP were not abolished by pempidine or by dihydroergotamine and were only reduced to some degree by propranolol. The effect of catecholamines on pO₂ is evidently mediated through an increase in the O₂ consumption as a result of the effect of cyclic AMP; the action of cyclic AMP is basically direct, but in vivo it cannot take place through the adrenoreceptor; the compound 2,3-AMP reduces pO₂ and also the O₂ consumption.Department of Biochemistry, Krasnoyarsk Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR S. S. Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 2, pp. 177–180, February, 1977.     

Gastroduodenal mucosa prostaglandins participate in realization of the effect of the antiulcer drug venter

It is shown that in patients with ulcer disease endogenous biosynthesis of prostaglandins E and F_2α in gastric and duodenal mucosa is suppressed. In patients treated with Venter (sucralfat), ulcer healing is accompanied by enhanced prostaglandin production in both scar tissue and unaffected areas. Stimulation of prostaglandin E and F_2α, synthesis in the gastroduodenal mucosa followed by activation of their cytoprotective effect in the gastrointestinal system is a key mechanism underlying the effect of Venter. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 7, pp. 90–93, July, 1998     

Effect of melatonin on cyclic nucleotide content and intensity of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypoxia

Single intraperitoneal injection of melatonin in a dose of 1 mg/kg prevented accumulation of cGMP and intensification of lipid peroxidation in the hippocampus and habenula of rats exposed to acute hypobaric hypoxia (12,000 m). Changes in habenular content of cGMP suggest that melatonin prevents hypoxia-induced activation of heme-oxygenase. Translated fromByulleten' Eksperimental" noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 168–171, August, 2000     

Adaptation to physical load increases the activity of prostaglandins E and I2 and reduces stress reaction

Adaptation to physical load protects against stress and other damage. It is suggested that this protection is associated with activation of prostaglandins E (PGE) and I₂ (PGI₂). Plasma contents of PGE₂, PGI₂, and thromboxane A₂ (TxA₂) and the severity of stress reaction are measured in male Wistar rats adapted to swimming. Training increases the concentrations of these prostaglandins and the prostaglandin/TxA₂ ratio, reduces almost 2-fold the severity of stress reaction as assessed by the plasma corticosterone concentration and corticosterone/insulin ratio. After stress, the PGI₂ and PGI₂/TxA₂ in adapted rats were, respectively, 33 and 31% higher than in unadapted. These findings suggest that prostaglandins are involved in the reduction of stress reaction. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 12, pp. 622–624, December, 1996     

Time course of the binding of some prostanoids in the serum of mice with lewis lung carcinoma with spontaneous metastases. Effect of exogenous prostaglandins on tumor dissemination

It is shown that the ability of serum to bind some prostanoids changes depending on the stage of development of the primary tumor node. Surgical removal of the tumor modulates the binding of TxB₂. When the PGE₂ content increases in the organism, the PGE₂ binding in the serum is stepped up, and dissemination is enhanced. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, № 3, pp. 296–298, March, 1994. Presented by P. V. Sergeev, Member of the Russian Academy of Medical Sciences     

Investigation of the mechanism of action of ouabain and cyclic AMP of the transport of calcium ions by rat heart mitochondria

The action of ouabain and cyclic AMP on the Ca-accumulating capacity and outflow of Ca²⁺ ions from loaded rat heart mitochondria was studied by the tetracycline probe method. In the course of the investigations no effect of ouabain on these processes was found. Cyclic AMP did not act on Ca binding by the mitochondrial membrane but it induced rapid liberation of Ca²⁺ from organelles loaded with these ions.Department of Molecular Pharmacology, Medico-Biological Faculty, N. I. Pirogov Second Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR S. S. debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 2, pp. 158–160, February, 1977.     

Immunoenzyme assay of glycocalicin, platelet glycoprotein Ib fragment. Evaluation of platelet turnover in circulation and differential diagnosis of thrombocytopenia

We propose a method for measurement of plasma glycocalicin, a fragment of platelet membrane glycoprotein Ib. The concentration of glycocalicin is elevated in thrombocythemia and reduced in thrombocytopenia caused by insufficient platelet production, but not in immune thrombocytopenia due to enhanced platelet degradation. Thus, plasma content of glycocalicin is an indicator of platelet turnover. The proposed assay can be used for differential diagnostics of thrombocytopenia. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 128, No. 10, pp. 476–479, October, 1999     

Significance of adenylate cyclase system of the liver in its chronic diseases

The activity of adenylate cyclase in the hepatocyte plasma membranes, content of cAMP, and cAMP/cGMP ratio in the liver and blood plasma are decreased in patients with chronic liver diseases (fatty dystrophy, chronic hepatitis, and cirrhosis). This decrease depends on the disease severity and is most pronounced in cirrhosis. The sensitivity of liver adenylate cyclase to insulin and glucagon is changed. It is concluded that disorders in the adenylate cyclase system are an important molecular mechanism in the pathogenesis of chronic liver diseases. Translated fromByulleten' Eksperimental'noi Biologii i Medistiny, Vol. 124, No. 4, pp. 450–453, April 1998