Blood Glucose Levels In Rats Research Articles

Hypoglycaemic Agent(s) in Leaves ofElaeophorbia drupifera

Male white Wistar rats (250–300 g), after an overnight fast, were treated with a crude extract (20 mg/kg oral) from the leaves of E. drupifera. The extract was administered 2 h before and 2 h after either an oral glucose load (3 g/kg) or a subcutaneous injection of adrenaline (0.01 mg/kg). The results showed that the extract reduced the blood glucose levels in rats that received the extract 2 h before glucose and adrenaline administration by about 34.3% and 35.2%, respectively. For the group that received the extract 2 h after glucose and adrenaline administration, the blood glucose levels were reduced by about 52.8% and 29.7%, respectively. Comparison was made between the action of the extract and a known hypoglycaemic drug — glibenclamide (0.29 mg/kg oral). The extract (20 mg/kg oral) was found to be faster and more effective than glibenclamide in lowering the blood glucose levels in fasting rats.

Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes.

The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs. Multilamellar liposomes consisting of dipalmitoylphosphati-dylcholine (DPPC)and dicetyl phosphate (DCP) (DPPC: DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored. The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats.

The effects of peripheral serotonin2 (5-HT2) and serotonin3 (5-HT3) receptor agonists on blood glucose levels in rats.

The involvement of the peripheral serotonin2A (5-HT2A) receptor in alpha-methyl-5-HT-induced hyperglycemia was examined in rats. The 5-HT2A receptor antagonist, ketanserin, significantly inhibited alpha-methyl-5-HT-elicited hyperglycemia. Taken together with a previous report that 5-HT-induced hyperglycemia was prevented by ketanserin, it is suggested that the peripheral 5-HT2A receptor participates in glucose regulation. As alpha-methyl-5-HT increased serum insulin but did not affect glucagon levels, it is indicated that these pancreatic hormones are probably not related to alpha-methyl-5-HT-induced hyperglycemia. Moreover, the peripheral 5-HT3 receptor agonist, 2-methyl-5-HT, did not affect blood glucose, insulin or glucagon levels. Our results therefore suggest that the peripheral 5-HT3 receptor is not involved in glucose regulation.

Orally Active and Long-Term Acting Insulin-Mimetic Vanadyl Complex: Bis(Picolinato)oxovanadium(IV)

The blood glucose level of rats with streptozotocin (STZ)-induced diabetes has been found to be normalized by administration of vanadyl or vanadate complexes. During our investigations on the development of anti-diabetic vanadyl complexes with various types of coordination mode such as V-O, V-N and V-S, we found that a new bis(picolinato)oxovanadium (TV) complex (VPA) has a strong insulin-mimetic effects as evaluated by an in vitro experiment, in which the inhibition of free fatty acid release in isolated rat adipocytes treated with epinephrine was observed to be similar to that of insulin. VPA was also effective for normalizing the blood glucose level of STZ-induced diabetic rats when given intraperitoneally or orally. The serum glucose level was maintained in the normal range for about 30 days with body weight gain after the end of oral administration of VPA for 14 days. VPA was confirmed to be an orally active and long-term acting insulin-mimetic vanadyl complex to treat insulin-dependent diabetes mellitus (IDDM) in rats.

実験的糖尿病発症ラットにおいてマイタケ投与が耐糖能および尿糖排せつに及ぼす効果について

The effects of Maitake (Grifola frondosa) on blood glucose level in rats with streptozotocin-induced diabetes were investigated. Diabetic rats were produced by injecting 80mg/kg streptozotocin (STZ) into 2-day-old neonates. From the age of 9 weeks, the rats were given Maitake as a dietary admixture at 20% food weight for 180 days. Diabetic rats showed obvious diabetic symptoms such as hyperglycemia, hyperphagia, polydipsia, polyuria and glucosuria. The diabetic levels of blood glucose, water consumption, urine volume and glucosuria were significantly decreased in the rats fed Maitake. From these results, it may be considered that the bioactive substances present in Grifola frondosa ameliorate the symptoms of diabetes.

Effect of pazufloxacin on blood glucose levels in rats

Effect of pazufloxacin on blood glucose levels in rats

Effect of inhibition of hepatic fatty acid oxidation on metabolic and hormonal responses to exercise in rats.

The purpose of the present study was to assess the effects of 2-mercaptoacetate (MA), an inhibitor of hepatic fatty acid oxidation, on the metabolic and pancreatic hormone response to a prolonged (3 h) swimming exercise. All rats were first adrenodemedullated and were either submitted for 3 weeks to a normal (5% fat) or a medium-fat diet (MF; 18% fat). After being submitted to an exercise swimming habituation programme for one week, rats under both dietary conditions were either injected with a bolus dose of MA (600 mumol/kg; ip) or with a saline solution. MA and saline injected rats were either sacrificed after a 3-h swimming exercise or after a 3-h resting period. Administration of MA was associated with a lower level of beta-hydroxybutyrate after exercise in rats fed the MF diet, higher resting and exercising blood glucose levels in rats fed the MF diet, and higher resting and exercising levels of hepatic glycogen in rats fed a normal diet. There were, however, no significant effects of MA on free fatty acid, insulin, glucagon, epinephrine, and norepinephrine concentrations in both dietary conditions either at rest or after exercise. Therefore, the present data do not provide any evidence that the administration of MA, an inhibitor of hepatic fatty acid oxidation, influences the pancreatic hormonal response to exercise. There was also no evidence of a lowering effect of MA on blood glucose levels during exercise.

Combination of microdialysis and glucosensor permits continuous (on line) SC glucose monitoring in a patient operated device. II. Evaluation in animals.

The microdialysis technique was used for following the glucose content of the extracellular subcutaneous (SC) fluid under varying blood glucose levels in rats. The glucose content in the microdialysis perfusion fluid was continuously analyzed by means of the measuring flow chamber of an ex vivo glucose monitor. In six ChBB rats blood glucose levels were varied between 40 mg/dl and 575 mg/dl by intravenous (IV) infusion of glucose and by SC injections of insulin, respectively. After a running-in period of about half an hour, the glucose content in the perfusion fluid was closely related to the blood glucose concentration (r > 0.92) up to a time period of 6 hrs. The "relative recovery" rate of glucose by the microdialysis probe in the SC tissue varied within the 6 experimental sessions. The relative recovery rate could be shown to be not dependent on the absolute blood glucose levels in the individual rat within the glucose concentration range tested.

P-489 - Effects of the 5-HT1A receptor agonist buspirone on blood glucose levels in rats.

P-489 - Effects of the 5-HT1A receptor agonist buspirone on blood glucose levels in rats.

Insulin-like effect of vanadyl ion on streptozotocin-induced diabetic rats

Recent studies have indicated that the blood glucose level of rats with streptozotocin (STZ)-induced diabetes (type 1) is normalized without an increase in the plasma insulin level by administration of sodium orthovanadate in the drinking water. The mechanism of this insulin-like effect of vanadate is unknown. In this study, we investigated whether vanadyl ion, which is less toxic than vanadate to rats, also has an insulin-like effect in rats with STZ-induced diabetes. When rats with STZ-induced diabetes were given a daily i.p. injection of vanadyl sulphate (9.3 and 4.6 mg vanadium/kg body weight), their blood glucose level decreased from about 22.2 to about 7.2 mmol glucose/l within 2 days and remained low for at least 12 weeks. This treatment did not affect their low plasma insulin level. Quantitative electron spin resonance (ESR) spectrometry showed that most of the vanadium (about 90%) in their tissues was present as a vanadyl form (VO2+). ESR analysis also showed that the vanadyl ion in tissues was bound endogenously with four oxygen ligands from either water or oxyamino acid residues in proteins. Vanadyl sulphate accelerated glucose incorporation into adipocytes of rats, suggesting that the action of vanadyl ion is peripheral. Interestingly, vanadyl sulphate at a high concentration (about 10 mmol/l) was more effective than insulin in enhancing glucose uptake. This study demonstrated that: (1) vanadyl sulphate (+4 oxidation state), like vanadate ion, normalizes the blood glucose levels of rats with STZ-induced diabetes; (2) the action of vanadyl ion is peripheral; and (3) the active form of vanadium for an insulin-like effect may be a vanadyl form, not vanadate.

Effects of the extracts of Ganoderma lucidum on blood glucose level in rats.

The water extract of Ganoderma lucidum was found, by the oral glucose tolerance test (OGTT), to reduce blood glucose and insulin 10 min after oral glucose infusion as compared to control rats. In addition, the water extract increased blood insulin 30 min and 60 min after oral glucose infusion without affecting blood glucose level as compared to control rats. Intravenous infusion of adrenaline with the oral glucose tolerance test (OGTT) caused an increase of blood glucose without elevating blood insulin level, as found by the oral glucose tolerance test (OGTT). The water extract of G. lucidum reduced the elevation of blood glucose without elevating blood insulin by the intravenous infusion of adrenaline and oral infusion of glucose.

Effect of four flavonoids on blood glucose of rats

The effects of aglycones morin and quercetin and their corresponding glycosides quercitrin and rutin were studied on the blood glucose levels of rats. Quercetin and quercetrin caused hypoglycaemia in rats, while rutin and morin showed almost no difference. Quercetin, which showed 50% pronounced hypoglycaemic effect, reduced significantly the blood glucose level of alloxan diabetic rats.

Hypothalamic involvement in the hyperglycemia and satiety actions of somatostatin in rats.

To determine whether the anorexic and the hyperglycemia actions of somatostatin were mediated through the hypothalamic nuclei, rats were infused with somatostatin and normal saline through previously implanted hypothalamic cannulae. Administration of somatostatin (0.5-1.5 microgram in 1.0 microliter) into the lateral hypothalamus, but not the ventromedial or the anterior hypothalamus, caused a reduction in food consumption without affecting relative water intake (or water-to-food ratio) in conscious rats in a freely moving state. On the other hand, administration of somatostatin into the lateral hypothalamus, but not the anterior or the ventromedial hypothalamus, caused an increase in blood glucose level in rats. This hyperglycemia was antagonized by vagotomy, but not by spinal transection or adrenalectomy. The data indicate that the lateral hypothalamus is the most sensitive site of the somatostatin-induced anorexia and the action of somatostatin on the lateral hypothalamus-vagus efferent activity is also a possible mechanism mediating hyperglycemia in rats.

Immunohistochemical and electron microscopic changes in the endocrine pancreas after thymectomy.

This study showed that six months after adult thymectomy blood glucose level in rats was significantly lower compared to that of control animals. The low glucose level found in thymectomized rats was accompanied by structural changes in the pancreatic islets. Electron microscopy and paraldehyde fuchsin (PAF) stained paraffin sections revealed partial degranulation of B-cells.

The influence of a new compound, PATP, on glucose transport in the isolated fat cell

A newly synthesized compound, N-(4-pyridylcarbonyl amino) 1, 2, 3, 6 tetrahydropyridine (PATP) was earlier found to elevate the blood glucose level in rats. This suggested that the compound might be accomplishing this by blocking glucose transport into tissue cells. This hypothesis has now been examined in the isolated fat cell system using a modification of the method to improve the accuracy of measurements made. This study indicated that PATP is a competitive inhibitor of glucose transport and metabolism (K I = 0.89 mM) but could not unequivocally prove that the effect was on transporter action alone. That the compounds action was at this level, however was shown by its ability to inhibit the uptake of the transported but non-metabolized sugar, 3-0-methyl glucose (K I = 3 mM). PATP is a non-phenolic inhibitor of glucose transport unrelated in structure to the sugar or to another more potent inhibitor, phloretin.

Effect of forskolin on islet cyclic AMP, insulin secretion, blood glucose and intravenous glucose tolerance in rats.

The in vivo effect of forskolin on insulin release, blood glucose and intravenous glucose tolerance test has been studied in the rat. In addition in vitro experiments on the effect of forskolin on islet cAMP and insulin release have been performed for comparison purposes. In batch incubated islets forskolin increased cAMP levels concentration dependently, the EC50 being approximately 25 microM. The maximal effect occurred after 5 min. In the presence of 2.8 mM glucose 10 microM forskolin did not stimulate insulin release; however, it potentiated both phase of 11.1 mM glucose induced insulin secretion. I.v. administration of 1.5 mg/kg of forskolin increased blood glucose levels in rats, which was associated with significant elevation of serum insulin. During an i.v. glucose tolerance test forskolin potentiated the insulin releasing capacity of glucose but did not significantly affect blood glucose levels. It is conceivable that cAMP per se does not initiate but rather amplifies insulin release by glucose. Since the synergistic effect of forskolin and glucose on insulin release in vivo is not associated with increased elimination rate it is possible that forskolin exhibits additional effects which counteract the glucose lowering action of insulin.

Hypoglycemic activity of l-α-(3,4- dimethoxyphenethylaminomethyl)-2- hydroxybenzylalcohol [formula omitted] fumarate (TA-078) in the mouse, rat and dog

l-α-(3,4-Dimethoxyphenethylaminomethyl)-2-hydroxybenzylalcohol 1 2 fumarate (TA-078) is a new hypoglycemic agent structurally different from any existing hypoglycemic drug. It depresses the rise of blood glucose when it is orally administered to glucose-loaded mice, rats and beagle dogs at minimal doses of 1, 10 and 2.5 mg/kg, respectively. In contrast with tolbutamide, TA-078 hardly affected fasting blood glucose levels in rats and dogs and only weakly reduced fasting blood glucose levels in mice. Oral administration of TA-078 to KK mice also improved glucose tolerance, while no improvement was observed in streptozotocin-diabetic rats. TA-078 elevated plasma immunoreactive insulin (IRI) levels in mice and rats soon after its oral administration. In fasted rats, TA-078 caused only a transient increase in plasma IRI but did not affect plasma immunoreactive glucagon (IRG) levels in the early phase after its administration. On the other hand, tolbutamide induced a sustained increase in plasma IRI and a transient but marked decrease in plasma IRG. In perfused rat pancreas, TA-078 stimulated insulin secretion. The stimulation by 10 μg/ml TA-078 in the perfusion liquid required the presence of a normal concn (5.6 mM) of glucose, whereas the same concn of tolbutamide stimulated insulin release even at a low glucose concn (2.8 mM).

Behavioral regulation of the blood glucose level in rats

Rats bearing one or two intravenous (IV) or one intravenous and one intragastric (IG) chronic catheters, were allowed to press one or two levers controlling the IV injection of either insulin or glucagon alone, or insulin paired with glucagon or with a glucose solution IV or IG. It was shown that rats readily learned to press for the various solutions and exhibited a sustained pattern of self-injection specific to these solutions and to their combinations. The rats self-injected insulin, glucagon and glucose preferentially during the 20 min preceding and following meals. Alone, or in combination with other solutions, glucose and glucagon were self-injected preferentially before meals and insulin after meals. Consequently, glucose or glucagon to insulin self-injection ratios were inversed from the pre-meal to the post-meal periods. In addition, rapid alternations from one lever to the other were observed in the coupled self-injections of insulin and glucose or insulin and glucagon. No effects of the self-injections on the free feeding pattern were observed. The results are interpreted as evidence for the reinforcing effects of a correction of both hypoglycemia and hyperglycemia and for a role of these systemic primary reinforcements in the normal post-ingestive modulation of oral feeding responses.

Effects of progesterone, oestradiol and-or clomiphene on liver glycogen and blood glucose in intact and adrenalectomised rats during delayed implantation.

ABSTRACT Prolonged administration of progesterone alone caused significant changes in liver glycogen. Oestradiol-17β increased the liver glycogen 18 hours after the treatment. A single administration of clomiphene citrate on day 9 post-coitum (pc) inhibited the oestradiol or progesterone induced increase in hepatic glycogen. Bilateral adrenalectomy on day 3 pc abolished the changes in liver glycogen induced by progesterone, oestradiol and/or clomiphene. Administration of progesterone, oestradiol or clomiphene caused a decrease in blood glucose levels in rats during delayed implantation. Although the effects of progesterone and oestradiol on blood glucose levels were abolished by adrenalectomy, clomiphene induced changes persisted in the adrenalectomised rats. It is concluded that progesterone, oestradiol and/or clomiphene induced changes in liver glycogen are mediated through the adrenal glands. Changes in the blood glucose levels are discussed in relation to increased insulin level in the blood and also in relation to the increased glucocorticoid secretion following various treatments.

Blood glucose levels in adrenalectomized rats with an established sugar preference

Blood glucose levels in rats with an established sugar preference were compared to rats with no such preference before and after adrenalectomy. The results indicated that an established preference for sugar does not affect the milligram percentage of blood glucose under the present conditions. Regardless of the established preference, there were no significant differences between adrenalectomized groups for any of the postoperative periods.