Oral lactate intensifies insulin toxicity during severe insulin-induced hypoglycemia in mice

ABSTRACT We investigated whether oral lactate could prevent seizures and deaths in mice with severe hypoglycemia induced by a high dose of insulin. For this purpose, mice were fasted for 15 h and then given an intraperitoneal injection of regular insulin (5.0 U/kg or 10.0 U/kg). Immediately after insulin injection, the mice received an oral dose of saline (control), glucose (5.5 mmol/kg), or lactate (18.0 mmol/kg). Glucose and lactate levels were measured in the blood and brain before and after the seizures began. Glucose and lactate delayed (p < 0.05) the onset of seizures associated with severe insulin-induced hypoglycemia. Elevated (p < 0.05) brain levels of lactate were associated with an absence of seizures in mice that received glucose or lactate, suggesting that lactate could prevent convulsions associated with severe insulin-induced hypoglycemia. However, the same oral dose of lactate that delayed the onset of convulsions also increased the mortality rate. In contrast, diazepam (3.0 mg/kg) prevented seizures and markedly decreased the frequency of death during severe insulin-induced hypoglycemia. The results demonstrated that in contrast to oral glucose, oral lactate intensifies insulin toxicity.

Evaluation of the impact of orally administered carbohydrates on postprandial blood glucose levels in different pre-clinical models

ABSTRACT We developed a pre-clinical model in which to evaluate the impact of orally administered carbohydrates on postprandial blood glucose levels. For this purpose, we compared the effects of different carbohydrates with well-established glycemic indexes. We orally administered (gavage) increasing amounts (0.2, 0.4, 0.6, 0.8, and 1.0 g/kg) of sucrose and lactose to rats which had been fasted for 6 h or 15 h, respectively. In part of the experiments we administered frutose (gavagem). Three different models were compared for measuring postprandial blood glucose levels: a) evaluation of interstitial glucose concentrations by using a real time continuous glucose monitoring system; b) evaluation of glucose levels in blood obtained from the rat tail; c) evaluation of serum glucose levels in blood collected after decapitation. Our results showed that blood obtained from the tails of 15-h fasted rats was the best model in which to evaluate the effect of carbohydrates on postprandial blood glucose levels.

Efeitos da suplementação de fibras solúveis, dieta de cafeteria e exercício físico sobre aorta torácica de ratos / Effects of supplementation by soluble fibers, cafeteria diet and physical exercise on rats´ thoracic aorta

As fibras alimentares vêm despertando interesse de especialistas das áreas de nutrição e saúde. Elas contribuem para a redução do risco de desenvolvimento de doenças cardiovasculares, além de ajudar no processo de perda de peso, principalmente quando seu consumo é associado à atividade física. Entretanto existem poucos trabalhos associando o uso de fibras solúveis à uma dieta hipercalórica e ao exercício físico. Assim, objetivo desse estudo foi investigar os efeitos das fibras solúveis sobre a aorta torácica e perfil lipídico de ratos machos wistar sedentários e treinados submetidos à dieta de cafeteria. Os parâmetros morfométrico e estereológico: espessura íntima-média e densidade de volume do músculo liso e do colágeno e o perfil lipídico foram determinados. Não foram observadas alterações na espessura da parede vascular, densidade de volume do músculo liso e colágeno. No entanto, o perfil lipídico apresentou-se alterado com o uso da dieta de cafeteria. A fibra alimentar associada ao treinamento aeróbio e a uma dieta balanceada apresentou resultado eficaz, não alterando a morfologia do vaso.

Food fibers have recently been in the limelight of nutrition and health experts. They reduce the development of cardiovascular diseases and help in the process of loss weight especially when their intake is associated with physical activity. However, few studies are extant on the use of soluble fibers associated to a hypercalorie diet and physical exercise. Current analysis deals with the effects of soluble fibers on the thoracic aorta and lipid profile of sedentary and trained male Wistar rats subjected to a cafeteria diet. Morphometric and stereological parameters comprised mid thickness and density of the volume of the smooth muscle and collagen, and lipid profile. No changes were reported on the thickness of the vascular wall, density of volume of the smooth muscle and collagen. However, lipid profile was modified due to the cafeteria diet. Food fiber associated with aerobic training and with a balanced diet provided an efficacious result with no alteration in the vase´s morphology.

Investigation of the Acute Effects of Dry Extract of Glycine Max on Postprandial Glycemia in Rats

The acute effects of Glycine max (GM) on post prandial glycemia (PPG) in male Wistar rats were investigated. All substances were orally administered by gavage in overnight fasted animals. The elevation of PPG promoted by starch (1g/kg) was prevented by GM (2.5 mg/kg, 5.0 mg/kg, 7.5 mg/kg, 10.0 mg/kg, and 100.0 mg/kg). In conclusion GM showed potential antidiabetic effect.