Glucose In Rabbits Research Articles

Influence of olfactomy, photoperiodic factor and physical activity on the dynamics of circadian rhythm of blood glucose in rabbits

In our study, we analyzed changes in blood glycemic reactions in 30-, 90-, 180-, and 365-day-old rabbits under the influence of physical activity and interceptive stimulation. As a result of the activation of nervous, hormonal, and enzymatic regulatory mechanisms during short-term physical exercise, anabolic reactions of glucose metabolism in the body, regardless of age, are enhanced due to glycogen resources and an additional supply of glucose in the blood. Long-term, but also heavy, physical activity, on the contrary, enhances the catabolic side of glucose metabolism in the body and leads to a decrease in blood glucose levels. In our study, the determination of blood glucose levels in experimental rabbits of different ages was carried out after interoceptive stimulation, in particular, irritation of rectal mechanoreceptors with pressure 80-100 mm Hg. Based on these experimental facts, one can conclude that the mechanisms of interoceptive regulation, especially the central nervous and neuroendocrine mechanisms regulating the homeostatic state of the internal environment, are not fully formed yet in young animals and do not have a long-term effect on the level of glucose in the blood. Based on these experimental facts, it can be concluded that the mechanisms of interoceptive regulation, especially the central nervous and neuroendocrine mechanisms regulating the homeostatic state of the internal environment, have not been fully formed yet in young animals and do not have a long-term effect on the level of glucose in the blood. This can also be explained by the fact that the dynamic and rhythmic nature of blood glycemic reactions in young animals is not so pronounced. However, in older animals, these reactions, while maintaining their high dynamic and rhythmic properties, develop in the form of static hyperglycemia.

Acarbose attenuates migration/proliferation via targeting microRNA-143 in vascular smooth muscle cells under diabetic conditions.

Acarbose (an α-glucosidase inhibitor) has been demonstrated to reduce the progression of atherosclerosis without affecting serum levels of glucose in rabbits fed a high cholesterol diet. The main focus of recent atherosclerosis studies has been microRNA targets. However, the mechanism by which acarbose targets miRNA-mediated atherosclerosis remains unclear. This study aimed to evaluate the effect of acarbose on microRNA-related regulation of rat aortic vascular smooth cell line (A7r5 cell) migration and proliferation induced by diabetic conditions. We reported that acabose exhibit significantly inhibits proliferative and cell migration abilities in A7r5 cells. The expression of protein and levels of mRNA were measured by Western blot analysis and real-time PCR. Acarbose inhibited the phosphorylation of focal adhesion kinase (FAK) and phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), Ras signals, small GTPase proteins expression to attenuate cell migration and proliferation. Furthermore, acarbose upregulated the expression of miR-143, and transfected miR-143 mimic and its inhibitor to explore its mechanism. In conclusion, acarbose reduces VSMC migration and proliferation via upregulating miR-143 to inhibit Ras-related signaling, and potentially prevention of atherosclerosis.

Compatibility of Insulin Lispro, Aspart, and Glulisine with the Solo™ MicroPump, a Novel Miniature Insulin Pump

This study compared the stability of commercially available, rapid-acting insulin in the novel tubeless, skin-adhering Solo insulin pump over 6 days at extreme environmental conditions. Forty-eight pumps for each tested analog were loaded with three different insulin lots and operated at 30 U/day (three sets of 12 pumps) and 15 U/day (one set of 12 pumps) with basal/bolus delivery patterns for 6 days under extreme climatic (37 degrees C, 40% relative humidity) and mechanical (35 strokes/min) stresses. The insulin solutions dispensed were sampled periodically and analyzed for potency, related substances, high molecular weight proteins (HMWP), and preservative content by high-performance liquid chromatography techniques. Biological activity (bioidentity) was demonstrated by an abrupt decrease in blood glucose in rabbits. Solutions were inspected for visual appearance and measured for pH levels. During the 6-day sampling period, the potency of all insulin samples was maintained at 95.0-105.0% of the bulk solution concentration of the insulin vials. The levels of HMWP and related substances remained well below labeling limits. The preservative concentration decreased with time but remained bacteriostatic effective. Solutions maintained pH and clarity and were particulate free. The biological activity was verified. Insulin analogs lispro, aspart, and glulisine maintained physical, chemical, and biological properties for 6 days when used in the Solo MicroPump device.

Methylamine but not mafenide mimics insulin-like activity of the semicarbazide-sensitive amine oxidase-substrate benzylamine on glucose tolerance and on human adipocyte metabolism

It has been reported that benzylamine reduces blood glucose in rabbits, stimulates hexose uptake, and inhibits lipolysis in mouse, rabbit, and human adipocytes. In the presence of vanadate, benzylamine is also able to improve glucose disposal in normoglycaemic and diabetic rats. Such insulin-mimicking properties are the consequence of hydrogen peroxide production during benzylamine oxidation by semicarbazide-sensitive amine oxidase (SSAO). The aim of the study was to determine whether other SSAO-substrates could share such potential antidiabetic properties. Thus, mafenide, a synthetic antimicrobial sulfonamide structurally related to benzylamine, and which has been recently reported to interact with SSAO, was tested in the above mentioned models, in parallel with methylamine, a proposed endogenous SSAO-substrate. All tested amines stimulated glucose uptake and inhibited lipolysis in rat and mouse fat cells. Methylamine and benzylamine, but not mafenide, reduced the hyperglycaemic response during a glucose tolerance test in rabbits while the three amines tested were devoid of insulin-releasing activity under both in vivo and in vitro conditions. In human adipocytes, mafenide did not stimulate glucose transport since it was not a high-affinity substrate for SSAO and generated less hydrogen peroxide than benzylamine or methylamine. Therefore, mafenide could not be considered as an antidiabetic drug despite being oxidized and exhibiting insulin-mimicking effects in rat and mouse adipocytes. By contrast, the endogenous substrate methylamine improved glucose utilization in all in vitro and in vivo models, leading to consider novel SSAO substrates as drugs with potential anti-hyperglycaemic properties.

Effects of insulin-induced acute hypoglycemia and normoglycemic hyperinsulinemia on the retinal uptake and ocular metabolism of glucose in rabbits

Glucose is the principal metabolic substrate for the retina in mammals, being essential for maintaining the functional activity of the retina; it can be supplied to the tissue by both vitreous humor and blood. Yet, the impact of hypoglycemia on retinal glucose metabolism has been poorly investigated. We have therefore studied the effects of acute insulin-induced hypoglycemia on the glucose uptake and metabolism in the retina, by analyzing the hypoglycemia-induced changes in the ocular distribution and metabolic fate of [ 3H]-2-deoxy- d-glucose (2-DG) and [ 14C]- d-glucose, both injected in the vitreous body. Rabbits were rendered hypoglycemic by subcutaneous injection of insulin (0.8 and 1.2 IU/kg). Insulin-induced hypoglycemia increased both retinal [ 3H]-radioactivity levels and retina to vitreous humor ratio of [ 3H]-radioactivity levels ([ 3H]-[R/VH]). Radio-chromatography showed that hypoglycemia did not induce any change in the retinal conversion of 2-DG to 2-DG-6-phosphate, but increased the conversion of [ 14C]- d-glucose to [ 14C]-lactate. Normoglycemic hyperinsulinemia caused no change in either retinal [ 3H]-radioactivity levels or [ 3H]-[R/VH] while decreasing retinal [ 14C]-radioactivity levels and retina to vitreous ratios of 14C-radioactivity levels. These results indicate that acute hypoglycemia increases the uptake rate of glucose by the retina and suggest that normoglycemic hyperinsulinemia may decrease retinal lactate, possibly stimulating its removal from the retina.

A lipoprotein lipase-promoting agent, NO-1886, improves glucose and lipid metabolism in high fat, high sucrose-fed New Zealand white rabbits.

The synthetic compound NO-1886 is a lipoprotein lipase activator that lowers plasma triglycerides and elevates high-density lipoprotein cholesterol (HDL-C). Recently, the authors found that NO-1886 also had an action of reducing plasma glucose in high-fat/high-sucrose diet–induced diabetic rabbits. In the current study, we investigated the effects of NO-1886 on insulin resistance and β-cell function in rabbits. Our results showed that high-fat/high-sucrose feeding increased plasma triglyceride, free fatty acid (FFA), and glucose levels and decreased HDL-C level. This diet also induced insulin resistance and impairment of acute insulin response to glucose loading. Supplementing 1% NO-1886 into the high-fat/high-sucrose diet resulted in decreased plasma triglyceride, FFA, and glucose levels and increased HDL-C level. The authors also found a clear increased glucose clearance and a protected acute insulin response to intravenous glucose loading by NO-1886 supplementation. These data suggest that NO-1886 suppresses the elevation of blood glucose in rabbits induced by feeding a high-fat/high-sucrose diet, probably through controlling lipid metabolism and improving insulin resistance.

Effect of Caesalpina Bonducella Seeds on Blood Glucose in Rabbits

The seeds of Caesalpinia bonducella (L.) Flem. (Caesalpiniaceae) are sold in shops in Dar es Salaam, Tanzania, for the treatment of diabetes mellitus. A suspension of the powdered seed kernel in 0.5% carboxymethylcellulose (CMC) was tested for ability to lower blood glucose in fasted and glucose-fed normal albino rabbits. Following administration of 0.2, 0.4 and 0.8 g/kg body weight of the powder there was no difference in areas under the fasting blood glucose and oral glucose tolerance test (OGTT) curves as compared to controls given CMC (P > 0.05). Similarly, 0.2 g/kg body weight of the powder administered for 7 consecutive days had no effect on either fasting blood glucose or the clearance of a glucose load from the blood. However, 0.1 g/kg body weight chlorpropamide significantly decreased the area under the fasting blood glucose and OGTT curves as compared to controls given CMC (P = 0.05). Thus, contrary to a previous report, we could not detect any hypoglycaemic activity in the seeds of Caesalpinia bonducella growing in Dar es Salaam.

A Study of the Effect of Phyllanthus Amarus Extracts on Blood Glucose in Rabbits

Aerial parts of Phyllanthus amarus are used by Traditional Healers of Tanga, northeastern Tanzania, to control symptoms of non-insulin dependent diabetes mellitus (NIDDM). An aqueous extract of the aerial parts, 0.1 and 1 g/kg body weight, significantly enhanced clearance of glucose from the blood as compared to controls during an oral glucose tolerance test (OGTT), using normal fasted albino rabbits (P = 0.05). The two doses of the extract reduced the area under the OGTT curve by 7.8% and 11.4%, respectively. Both doses had no effect on blood glucose in the unfed rabbits. Chlorpropamide, 0.1 g/kg body weight, showed a greater effect, than both doses, on glucose clearance in the fed state and on blood glucose in the fasted rabbits (P = 0.05). A methanol extract of the aerial parts, 1 g/kg body weight, worsened glucose tolerance causing a significant increase in area under the OGTT and fasting blood glucose curves (P = 0.05). We conclude that the aqueous extract contains a hypoglycaemic activity as claimed...

Experimental study of efficacy and optimal dose of intraoperative glucose in rabbits under general anesthesia.

This experimental study was designed to investigate the efficacy of glucose loading during surgery. Rabbits, fasted overnight, received 20 ml·kg-1·h-1 fluid infusion containing glucose at various concentration (0,0.5, 1.0, 1.5, 2.0% w/v) for 3 h intraoperatively. Plasma glucose level increased after the beginning of operation, but the increase was slight in groups given 0.2 g·kg-1·h-1 or lower doses of glucose. Glucose at higher doses caused marked hyperglycemia. These higher doses also promoted urinary glucose excretion, and in the group given the maximum glucose dose (0.4 g·kg-1·h-1), this parameter was significantly elevated compared with findings in the 0.2 g·kg-1·h-1 group (P<0.05), whereas it showed no significant difference among groups given 0-0.2g·kg-1·h-1. The liver glycogen content in animals that received no glucose was significantly lower than that of the 0.2 g·kg-1·h-1 group (P <0.01). However, there was no correlation between glycogen level and glucose dose among groups receiving glucose. These results suggest that intraoperative glucose supplementation is effective in preventing glycogen depletion, and indicate that, to avoid glucose overloading, the optimal dose is 0.1-0.2 g·kg-1·h-1.

Experimental study of efficacy and optimal dose of intraoperative glucose in rabbits under general anesthesia

Experimental study of efficacy and optimal dose of intraoperative glucose in rabbits under general anesthesia

Intraocular distribution of topically administered insulin and effects on intraocular glucose in rabbits

Intraocular distribution of topically administered insulin and effects on intraocular glucose in rabbits

Hypoinsulinemic and hyperglycemic effects of beta-endorphin in rabbits.

The present study was designed to investigate the in vivo effects of beta-endorphin on plasma levels of glucagon, insulin and glucose in rabbits, and to elucidate some of the mechanisms involved. beta-Endorphin (50 micrograms) injected intravenously into fasted rabbits, decreased plasma levels of insulin (-4.5 +/- 1.3 microU/ml, P less than 0.05) and increased plasma levels of glucose (+2.7 +/- 0.4 mmol/l, P less than 0.05). Similar hypoinsulinemic and hyperglycemic effects were observed for 25 and 2.5 micrograms beta-endorphin in fasted and 50 and 0.5 micrograms beta-endorphin in fed rabbits. beta-Endorphin produced slight and transient increases in plasma levels of glucagon at the highest dose in fed rabbits, only (+80 +/- 9 pg/ml, P less than 0.05). The beta-endorphin-induced hypoinsulinemia was not inhibited by phentolamine, yohimbine, propranolol or atropine, which is in consistency with a direct inhibitory effect of beta-endorphin on the beta-cell in rabbits. The beta-endorphin-induced hyperglycemia was reduced by naloxone (+0.8 +/- 0.1 mmol/l) but not by N-methyl-naloxone (ORG 10908) a peripheral opiate receptor blocking drug (+2.2 +/- 0.2 mmol/l), suggesting a central nervous action on opiate receptors. This central action of beta-endorphin was probably not mediated by catecholamine release or other stimulation of adrenergic or muscarinic receptors, since the beta-endorphin-induced hyperglycemia was not inhibited by phentolamine, yohimbine, propranolol or atropine. These results suggest that the beta-endorphin-induced hyperglycemia was caused, at least in part, by a peripheral inhibition of insulin release and a central stimulation on glucoregulation.

Acute effects of oxytocin and vasopressin on plasma levels of glucagon, insulin and glucose in rabbits.

Acute effects of oxytocin and vasopressin on plasma levels of glucagon, insulin and glucose in rabbits.

171) - Effects of β-adrenergic blocking agents and hypoglycemic agents on blood glucose in rabbits

171) - Effects of β-adrenergic blocking agents and hypoglycemic agents on blood glucose in rabbits

Effect of Hypothalamic Stimulation on Blood Glucose in the Rabbit

Studies were carried out in rabbits to localize by electrical stimulation the sites in the hypothalamus that are concerned with the production of hyperglycemia, and to determine the contribution of the sympathetico-adrenal system in producing this effect. Stimulation of the anterior hypothalamic area, paraventricular nuclei, and rostral border of the ventromedial nuclei produced a significant elevation of blood glucose in normal rabbits and also in adrenal-demedullated animals. Corticotropin (ACTH), 2 U/kg, produced a hyperglycemia comparable to that observed following electrical stimulation, whereas growth hormone (GH), 2.5 mg/kg, had no effect on blood glucose. The data indicate that the anterior hypothalamus plays a part in the regulation of blood glucose, which is independent of the sympathico-adrenal system. It is suggested that the hyperglycemia produced by hypothalamic stimulation in these studies is due to the release of one or more anti-insulin factors by the anterior pituitary.

The effect of adrenergic blocking agents on plasma glucose in rabbits

The influence of phentolamine and propranolol on blood sugar was studied in normal and in hypoglycaemic rabbits. Phentolamine increased resting plasma glucose, and reduced the hypoglycaemic response to insulin. The percentage change in blood sugar induced by phentolamine was diminished during insulin hypoglycaemia. In contrast, propranolol decreased resting plasma glucose, increased the hypoglycaemic response to insulin and delayed the restoration of normal blood sugar levels. The relative effect of propranolol on plasma glucose was increased during hypoglycaemia. It was concluded that the effects of phentolamine on blood sugar were unrelated to alpha-adrenergic blockage. However, the effects of propranolol were consistent with antagonism of the beta-effects of circulating adrenaline.

Influence of endocrine glands on carbohydrate metabolism; effects of experimental hyperthyroidism and thyroidectomy on assimilation coefficient of glucose in rabbits.

Influence of endocrine glands on carbohydrate metabolism; effects of experimental hyperthyroidism and thyroidectomy on assimilation coefficient of glucose in rabbits.

Urethm Narosis, Influence of on the Specific Dynamic Action of Glycocoll and Glucose in Rabbits.

Urethm Narosis, Influence of on the Specific Dynamic Action of Glycocoll and Glucose in Rabbits.