Dynamics of insulin secretion in dogs with alloxan diabetes

Hypoinsulinemia in the superior pancreatico-duodenal vein and depression of the first phase of insulin secretion by the pancreas, characteristic of alloxan diabetes of different degrees of severity, are not observed in the femoral vein. The results of an investigation of the dynamics of the insulin and glucose concentrations in the superior pancreatico-duodenal vein emphasize the dominant role of the pancreatic factor in the pathogenesis of alloxan diabetes in dogs. Data obtained by the study of these indices in the peripheral femoral vein do not reflect this state of affairs adequately.Laboratory of Pathological Physiology, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Department of Normal Physiology, North-Ossetian Medical Institute, Ordzhonikidze. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 3, pp. 278–281. March, 1978.     

Development of diabetes mellitus in the offspring of female rats with alloxan diabetes in six generations

S. M. Kirov Leningrad Postgraduate Medical Institute. Institute of Obstetrics and Gynecology, Academy of Medical Sciences of the USSR. I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR. Genetics Center, Leningrad. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 105, No. 1, pp. 13–15, January, 1988.     

Lymphocyte kinetics in mice with alloxan diabetes

Central Research Laboratory, Tyumen' Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR N. V. Vasil'ev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 10, pp. 404–406, October, 1990.     

Mechanisms of inhibition of synaptic transmission in the sympathetic ganglia of rats with alloxan diabetes

In experiments on isolated cranial sympathetic ganglia of rats with alloxan diabetes the preganglionic nerve was stimulated and combined presynaptic action potentials (APs) and EPSPs of neurons of the ganglion were recorded. In rats with moderately severe alloxan diabetes progressive depression of rhythmic APs of the ganglion correlated completely with inhibition of the excitatory power of the presynaptic endings, i.e., with a decrease in the liberation of mediator and exhaustion of its operative fraction. In rats with the severe form of diabetes postsynaptic inhibition of neurons of the ganglion also was observed. The dynamic characteristics of conversions of the mediator, assessed on the basis of examination of posttetanic potentiation patterns, showed a very small change in the output of mediator but a substantial (by 38%) depression of replenishment of the mediator reserves per second compared with the control.Laboratory of Physiology of the Autonomic Nervous System, I. P. Pavlov Institute of Physiology, Academy of Medical Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 9, pp. 272–274, September, 1978.     

Insulin sensitivity of muscle tissue isolated from rats with manifest alloxan diabetes of varied duration

Sensitivity of muscle tissue to insulin was studied by measuring the intensity of its action on incorporation of labeled glucose into glycogen by the isolated diaphragm of 20 control rats and 27 rats with alloxan diabetes. If the duration of diabetes was 5–8 days the sensitivity of the muscle tissue to insulin was unchanged. After alloxan diabetes lasting 22–24 days, a significant decrease was found in the sensitivity of the muscle tissue to insulin. With an increase in the duration of decompensated alloxan diabetes to 5–8 months, a further decrease in incorporation of labeled glucose into glycogen by the diaphragm was observed. The results show that the sensitivity of muscle tissue to insulin is reduced by metabolic disturbances characteristic of diabetes mellitus.Laboratory of Physiology and Pathology of the Human Endocrine System. I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. G. Baranov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 10, pp. 412–414, October, 1979.     

Effect of estradiol on prolactin secretion by adenohypophyseal cells of intact and ovariectomized rats in primary monolayer cultures

Estradiol directly stimulated prolactin secretion by adenohypophyseal cells of intact rats in monolayer culture. Complex relations between estradiol and certain other regulators of the function of the pituitary lactotrophs were found. Changes in the synthesis and secretion of prolactin in animals with disturbed function of their gonads were shown to continue for 3 or 4 days during culture of adenohyphyseal cellsin vitro.Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 7, pp. 92–94, July, 1979.     

Changes in the count of pancreatic beta- and alpha-cells and blood glucose level in rats with alloxan-induced diabetes

We estimated the count of pancreatic alpha- and beta-cells and blood glucose level at various stages of alloxan-induced diabetes in rats. Alloxan decreased the count of insulin-producing beta-cells, but increased the number of glucagon-secreting alpha-cells in the pancreas (week 1 of diabetes). These changes were accompanied by hyperglycemia. The decrease in blood glucose level in diabetic rats was associated with an increase in beta-cell count against the background of high density of pancreatic alpha-cells.     

Role of metabolic regulators in the assimilation of casein hydrolysate in alloxan diabetes

Experiments on rats with alloxan diabetes showed that administration of metabolic regulators (insulin, vitamin C, vitamins of the B group, and nerobolyl) increases the assimilability of casein hydrolysate, as shown by the positive nitrogen balance, maintenance of body weight, and increase in the dry residue of the tissues. The results provide further experimental verification of the need to create hydrolysates with vitamins and hormones in order to make parenteral feeding more effective.Experimental Division, Research Institute of Hematology and Blood Transfusion, L'vov. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 5, pp. 560–561, May, 1976.     

Regulation of hormonal secretion and DNA synthesis in lactotrophs of the rat adenohypophysis in primary cell culture in vitro

Laboratory of Biological Investigation of Hormonal Compounds, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Department of Morphology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. A. Pankov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 105, No. 4, pp. 481–483, April, 1988.     

Structural changes in components of the blood-retina barrier in rat retina during photodamage in alloxan diabetes and their correction with ascovertin

The outer part of the blood-retina barrier was most sensitive to light exposure (6000 1x, 6 h) during photodamage. It was manifested in hemodynamic disturbances, endothelial dysfunction, and focal death of the pigment epithelium. The photo effects increased during alloxan diabetes. The specific area of open vessels decreased, while the number of thrombotic vessels in the choroid increased. Administration of ascovertin improved hemodynamic parameters of the eye and decreased the specific area of focal damage. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 12, pp. 703–706, December, 2007     

Transcranial electrostimulation activates reparative regeneration and the insulin-producing function of pancreatic B-cells in alloxan diabetes in rats

Studies on rats with experimental diabetes induced by administration of alloxan showed that transcranial electrostimulation of endorphinergic brain structures stimulates the regeneration of damaged β-cells in pancreatic islets of Langerhans. This was identified on pancreatic sections stained with hematoxylin and eosin. De novo formation of small islets was noted, as evidenced by their regeneration from progenitor cells. After transcranial electrostimulation, islet β-cells stained by the Gomori method showed recovery of granularity-a sign of insulin production. Application of an immunoenzyme method demonstrated recovery of blood insulin levels, the dynamics of increases in which showed a highly significant negative correlation with a decrease in blood glucose. These data led to the conclusion that the antihyperglycemic effect of transcranial electrostimulation in experimental alloxan diabetes results from reparative regeneration of β-cells in islets of Langerhans with recovery of their insulin-producing function. __________ Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 92, No. 2, pp. 204–213, February, 2006.     

Tissue-specific reduction of galanin content in the pancreas in alloxan diabetes in the mouse

Galanin inhibits insulin secretion and has been proposed to function as a sympathetic neurotransmitter in the endocrine pancreas in some species, for example in the dog. In this study, pancreatic and adrenal gland galanin content were measured following experimental diabetes induced by alloxan in mice. Three days after administration of alloxan (70mgkg^-1, i.p.) in normal mice, pancreatic content of galanin-like immunoreactivity (GLIR) was reduced to 65 ± 11 % of that in untreated controls (P < 0.01), whereas adrenal gland GLIR was unchanged. Similarly, 8 days after alloxan administration, pancreatic GLIR was reduced (P < 0.002), whereas adrenal gland GLIR was unaffected. Pancreatic GLIR also inversely correlated with plasma glucose levels (r = -0.5055, P < 0.005). To distinguish between the direct effects of alloxan vs. indirect metabolic effects induced by the drug, alloxan-diabetic mice were treated with insulin twice daily, which normalized the plasma glucose levels (7.6 ± 0.3 mmol l^-1). Pancreatic GLIR was then not significantly different from controls. Thus pancreatic but not adrenal gland GLIR content is reduced in alloxan-induced diabetes in mice. The data support a role for galanin as a pancreatic sympathetic neurotransmitter which may participate in the metabolic alterations seen in alloxan diabetes in mice.     

Effect of thyrotropin releasing hormone and thyroxine on cytochrome oxidase activity in the rat adenohypophysis

Thyrotropin releasing hormone (TRH), in a dose of 0.01 and 1.0 g/ml, sharply increased cytochrome oxidase activity in the adenohypophysis of rats fed for 6 weeks with methylthiouracil. This effect of TRH on enzyme activity was blocked by thyroxine (T₄), if added to the incubation medium in a concentration of 20 g/ml. Actinomycin D (20 g/ml) prevented the blocking of cytochrome oxidase by T₄. TRH in a concentration of 0.01 g/ml and T₄, in a dose of 2.0 g/ml, caused no change in cytochrome oxidase activity in the adenohypophysis of intact and partially thyroidectomized rats.Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 11, pp. 559–562, November, 1977.     

Effect of thyrotrophin releasing hormone on secretion of thyrothrophic hormone and prolactin in a monolayer culture of rat adenohypophysis

Cells of the adenophypophysis in a primary 5–8-day monolayer culture react to addition of thyrotrophin releasing hormone (TRH) by rapid dose-dependent liberation of thyrotrophic hormone (TSH) and prolactin into the culture medium. This effect is independent of the content of serum in the nutrient medium. The thyroid hormone thyroxin blocks the stimulating action of TRH on the secretion of TSH, but not of prolactin. The blocking effect of thyroxin is evidently manifested not on cell membranes, but in the cytoplasm distally to the effect of cyclic AMP, along the pathway of transmission of the hormonal signal.Laboratory of Biological Standardization of Hormones, Institute of Experimental Endocrinology and Hormone Chemistry, Academy of Medical Sciences of the USSR, Moscow. Department of Morphology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Yudaev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 2, pp. 215–217, February, 1978.