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Biomedical subjects

M Azam

Publications and source records attributed to M Azam.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effect of hyperglycemia on acetylcholinesterase and catecholamine levels in rat brain and heart.

The effect of hyperglycemia due to experimental diabetes induced in rats, causes a decrease in the activity of Acetylcholinesterase in brain regions and heart; changes in the heart being more significant than the brain. Insulin administration reversed this effect in both the hear and the brain. Significant increase in the levels of catecholamines were also found in the brain regions in diabetes, which was reversed by insulin. The decreased activity of acetylcholinesterase observed in diabetes may be due to an early impaired glucose oxidation and glucose transport as a result of lack of insulin, which causes specific alterations in neurotransmitter levels, thereby effecting blood brain barrier transport, thus causing brain dysfunction.

Acetylcholinesterase↗
PubMed1991

Imipramine inhibits monoamine oxidase activity in hyperglycemic rat brain.

The effect of the chronic treatment of tricyclic antidepressants like Imipramine on the catecholamine metabolism of rat brain, in normal and hyperglycemic conditions was investigated. Imipramine was found to elevate the catecholamine levels in controls, while chronic treatment of hyperglycemic animals with the drug, failed to cause any change other than seen as a result of hyperglycemia. The activities of Monoamine oxidase on the other hand, decreases significantly as a result of the treatment, both in controls and in the hyperglycemic state. The results suggest that the drug apart from acting as an antidepressant, assumes the role of a monoamine oxidase inhibitor under pathological conditions.

Animals↗
PubMed1990

Enhancement of rat brain cytosolic monoamine oxidase activity by clorgyline. Comparison with (-)-deprenyl and MDL 72145.

The presence of unsedimentable forms of monoamine oxidase (EC 1.4.3.4) in liver and brain homogenates has prompted fresh studies on the effects of inhibitors on this cytosolic monoamine oxidase. Clorglycine is a specific monoamine oxidase A inhibitor and (-)-deprenyl and MDL 72145 are specific monoamine oxidase B inhibitors. We investigated the effects of (-)-deprenyl, MDL 72145 and clorgyline on the purified enzyme from mitochondria and cytosolic monoamine oxidase along with high speed cytosol and 1% Triton X-100 treated mitochondrial preparations. Clorgyline enhanced the activity of the purified enzyme several-fold. (-)-Deprenyl and MDL 72145 also enhanced and inhibited the activity of cytosolic monoamine oxidase in a concentration-dependent manner.

Allylamine↗
PubMed1990

Purification and immunochemical interrelationship of insulin receptors from rat brain and liver.

Insulin receptors from rat brain and liver were purified. Brain purified receptor exhibited protein bands of apparent Mr = 135,000 and 95,000 molecular weight corresponding to alpha- and beta-subunits, retained a tyrosine specific protein kinase activity and demonstrated phosphorylation that is hormonally sensitive. Antisera were raised against both insulin receptor preparations and enzyme-linked immunosorbent assay was developed. The comparison of two insulin receptors was based on a displacement enzyme-linked immunosorbent assay where antisera were interchanged on predetermined optimal dilutions. This indicated that both insulin receptors possess some unique antigenic determinants thereby implying a structural difference.

Animals↗
PubMed1990

Effect of chronic administration of propranolol on acetylcholinesterase and 5-hydroxytryptamine levels in rat brain and heart.

The effect of chronic administration of propranolol on the rat brain and heart acetylcholinesterase was studied by administering propranolol (5mg/kg body weight) for 14 days. This treatment was found to substantially inhibit the enzyme activity. Levels of 5-hydroxytryptamine were measured in the brain and heart; in brain the levels of 5-hydroxytryptamine increased with propranolol administration, while in the heart there was no change. Effect of different concentrations of propranolol on acetylcholinesterase activity was also studied in vitro and a decreased activity of the enzyme was found in brain and heart homogenates. The significance of these results is discussed in terms of the therapeautic effects of the drug in the control of hypertension.

Animals↗
PubMed1990

Changes in the levels of catecholamines, hexokinase and glucose 6-phosphate dehydrogenase in red cell aging.

The activity of the enzymes hexokinase and glucose 6-phosphate dehydrogenase and the level of catecholamines were measured in isolated rat Red Blood Cells (RBC) during cellular aging. The results clearly showed a linear decline in the two enzyme profiles with corresponding increase in age of RBC. A decrease of 75-85% in the activities were found in the oldest cell fractions as compared to the youngest. The levels of glycosylated haemoglobin and catecholamines were found to increase with aging. A correlation can probably be established between the enzyme activities, the levels of glycosylated haemoglobulin and catecholamines during aging.

Animals↗
PubMed1990

Modulation of insulin receptors and catecholamines in rat brain in hyperthyroidism and hypothyroidism.

Insulin receptor activity and its relationship with catecholamines and serotonin were investigated in rat brain using Triton X-100 extracts from total membranes, synaptosomes and choroid plexus in experimental hypothyroidism and hyperthyroidism. Insulin receptor activity was assessed by binding to [125I]insulin and catecholamines by high performance liquid chromatography. In choroid plexus thyronines effects are well pronounced and there is modulation vis a vis plasma hormone concentrations. Triiodothyronine levels increase in brain in all experimental groups. This suggests that rat may serve as a useful model for thyronine homeostasis in brain and there may be involvement of very complex regulatory mechanisms in glucose tolerance.

Animals↗
PubMed1990

Effect of hyperthyroidism and hypothyroidism on rat red blood cell insulin receptors and catecholamines: relationship with cellular ageing.

Insulin receptor activity and its relationship with catecholamines in rat young, middle aged and old red blood cells were investigated in experimental hypothyroidism and hyperthyroidism. In control animals, a loss of insulin receptor activity was found with cellular ageing and increased levels of norepinephrine, epinephrine and glycosylated hemoglobin. There was down regulation of insulin receptors together with alterations in membrane bound catecholamines in thyroid hormones imbalances. These results suggest that loss of insulin receptor in cellular ageing is probably part of a more generalised alteration and rat serves as an excellent model in defining the role of thyroid hormones in carbohydrate tolerance.

Animals↗
PubMed1990

Rat brain insulin degrading enzyme in insulin and thyroid hormones imbalances.

Rat brain insulin degrading enzyme activity and its relationship with insulin receptor were investigated in experimental hyperglycemia, hyperinsulinemia, hypothyroidism and hyperthyroidism. Insulin degrading enzyme activity was assessed in synaptosomes and high speed cytosol using [125I]insulin. Levels of insulin degrading enzyme were changed in high speed cytosol in insulin and thyroid hormone imbalances. These results suggest that insulin degrading enzyme in brain is predominantly active in cytosol and is subject to regulation by insulin and thyroid hormones. Probably it plays some role in long term effects of insulin in brain.

Animals↗
PubMed1990

Changes in erythrocyte glutathione peroxidase and glutathione reductase in alloxan diabetes.

Glutathione peroxidase and glutathione reductase activities were measured in erythrocytes from control, diabetic and insulin-treated diabetic rats. A significant decrease in the activity of glutathione peroxidase and an increase in the glutathione reductase activity were found with increase in the time of diabetes which may result in the alteration in the activity of the pentose phosphate pathway by the modulation of the levels of NADPH. Insulin administration reverses the change in the activity of glutathione peroxidase but does not reverse the glutathione reductase activity during diabetes. The overall changes may be due to changes in the levels of insulin, triiodothyronine and thyroxine.

Animals↗
PubMed1990

Modulation of insulin receptors and catecholamines in rat brain in hyperglycemia and hyperinsulinemia.

Insulin receptor activity and its relationship with catecholamines and serotonin were investigated in rat whole brain membranes, synaptosomes and choroid plexus in alloxan induced short term and long term hyperglycemia and hyperinsulinemia. Insulin receptor activity was measured by [125I]insulin binding and catecholamines by high performance liquid chromatography with electrochemical detection. While choroid plexus insulin receptors modulate along with norepinephrine, dopamine and serotonin with the changes in insulin and/or plasma glucose levels, insulin receptor activity in synaptosomes and total membranes is not affected to a great extent except in long term hyperglycemia.

Alloxan↗
PubMed1990

Effect of hyperglycemia and hyperinsulinemia on rat red blood cell insulin receptors and catecholamines: relationship with cellular ageing.

Insulin receptor activity and its relationship with catecholamines in rat young, middle aged and old red blood cells were investigated in short term (4-6) weeks and long term (6-8 months) hyperglycemia and hyperinsulinemia. Loss of insulin receptor activity is linear with cellular ageing and norepinephrine and epinephrine levels increase with age together with levels of glycosylated hemoglobin in control animals and this correlation is altered in hyperglycemia and hyperinsulinemia. These results suggest that loss of insulin receptor in cellular ageing is probably part of a more generalised alteration which is possibly brought about by glycosylation.

Animals↗