Effects of nutritive and nonnutritive stomach loads on plasma glucose level and lateral hypothalamic eating threshold in the rat

Excitability of the rat's lateral hypothalamic feeding system was determined by measuring the threshold for electrically induced eating. The effects of different stomach loads on the magnitude and time course of this threshold and of blood glucose concentration were investigated. In a first experiment, 10 ml loads of either 50% (w/v) dextrose (21 kcal), 20% dextrose (8.5 kcal), bulk (50% kaolin in water), or tap water were compared against mock intubations with the empty syringe. Thresholds rose within minutes after loading with glucose, to a maximum at about 30 min, and then normalized slowly in a precise dose-response relationship. The nonnutritive kaolin load produced a comparable threshold increase to 20% glucose, but reached its maximum as soon as 10 min after intubation. The tap water load did not differ significantly from the mock control. In a second experiment, isocaloric 10 ml loads (20 kcal) of either dextrose, casein-hydrolysate or an emulsion of soyabean-oil were compared against mock intubations. The protein load was less effective than glucose, and the fat load less effective than protein, in increasing thresholds. While the glucose load produced a marked hyperglycemia, both the protein and fat load did not. Also, protein and fat loads did not maintain satiety longer than the simple bulk load.     

Effects of insulin on food intake and plasma glucose level in fat-fed diabetic rats

Schedules of insulin treatment which reliably increased eating in fat-fed diabetic rats were studied for their effect on plasma glucose concentrations. An inverse correlation between intake and plasma glucose was observed in fat-fed diabetics given long-term treatment with protamine-zinc insulin (PZI); however changes in glucose did not account for the differential effect of insulin on food intakes in normal controls or normal and diabetic rats fed a low-fat food. A single injection of 1 U PZI which increased eating in fat-fed diabetics but not normal controls 17–23 hr later did not reduce glucose concentrations from hyperglycemic levels in diabetics during the same time period. Injections of regular insulin increased eating in fat-fed diabetic and normal rats in a comparable fashion, but did not reduce plasma glucose in diabetics as low as in normal animals. The results show that the effect of exogenously administered insulin on food intake in fat-fed diabetics is largely unrelated to changes in circulating glucose levels and suggest that metabolic consequences of insulin treatment other than hypoglycemia may underlie the effect of the hormone on feeding in these animals.     

慢性间歇性低氧对大鼠肾脏GLUT-2和IRS-2表达的影响

目的探讨慢性间歇性低氧及复氧对大鼠肾脏葡萄糖转运蛋白2(GLUT-2)、胰岛素受体底物2(IRS-2)表达的影响。方法将大鼠分为对照组(control)、慢性间歇性低氧组(CIH)和慢性间歇性低氧后复氧组(RH),建立慢性间歇性低氧的动物模型,抽取动脉血立即行血气分析,过氧化物酶法检测血清中血糖及放射免疫法检测大鼠血清胰岛素。取出大鼠肾脏组织,q PCR法检测大鼠肾脏GLUT-2、IRS-2的mRNA表达,Western blot法检测GLUT-2、IRS-2蛋白表达;免疫组化法检测大鼠肾脏GLUT2、IRS-2蛋白表达。结果 control组大鼠血氧饱和度≥95%,CIH组的血氧饱和度≤85%,RH组血氧饱和度≥86%;CIH组大鼠空腹血糖、血清胰岛素及胰岛素抵抗指数较control组、RH组明显升高(P0.05);RH组高于control组(P0.05);GLUT-2、IRS-2的mRNA及蛋白表达较control组和RH组升高(P0.05);RH组高于control组(P0.05)。结论慢性间歇性低氧升高大鼠空腹血糖,上调大鼠肾脏GLUT-2、IRS2的表达,增强胰岛素抵抗,降低胰岛素敏感性。     

Hypothalamic sensitivity to 2-deoxy-D-glucose and glucose: effects on feeding behavior

The effect on food intake of intrahypothalamic deposition of glucose or the glucose metabolic inhibitor 2-deoxy-D-glucose was studied to determine the function of the often hypothesized hypothalamic glucoreceptors in feeding behavior. Our results suggest that the lateral hypothalamic region, as well as the medial hypothalamus, contain glucoreceptive cells that form part of a feeding system.     

Feeding and arteriovenous differences of blood glucose in rats after injection with 2-deoxy-D-glucose and after food deprivation

Normal and adrenally demedullated rats injected with approximately 200 mg per kg of 2-deoxy-D-glucose (2-DG) ate just over 1 g more food than controls in 3-hr eating tests. This eating response was unaffected by delaying access to food by 30 min. Injections of 6-deoxy-D-glucose also increased eating, but less than 2-DG. Rats deprived of food for 24 hr ate about twice as much food as those injected with 2-DG. Drinking was increased following 2-DG in some but not all the experiments. Ether anaesthesia at the time of the injection depressed subsequent drinking but not eating. Arteriovenous differences of blood glucose (measured between carotid artery and jugular vein, and between carotid artery and femoral vein) were decreased after 24 hr deprivation of food, but slightly increased after injections of 2-DG. 2-DG stimulates eating without decreasing the rate of uptake of glucose from the blood.     

Plasma insulin and the time pattern of feeding in the rat

Blood levels of glucose and insulin during meals and between-meal-intervals were measured in virtually undisturbed rats. After a peak due to glucose absorbed from the meal blood sugar soon reverts to the pre-meal level. Insulin shows a similar peak followed by a continuing decline so that just before the next meal it is lower than at any other time. In terms of the glucostatic theory this might mean that meals are triggered by a critical drop of insulin. However, intravenous infusions of glucose, resulting in continously high insulin, do not affect timing or size of meals. Glucostatic factors probably are of minor importance in meal-to-meal regulation in the rat. However, they may subserve nutritional homeostasis on at least two other points.     

Fast-induced changes in plasma glucose, insulin and free fatty acid concentration compared in rats during the night and day

Changes in PG, PI and PFFA were examined and compared in fed rats or after 0 to 12 hours of fasting, during the night or during the day. At night, a progressive decrease in PG and PI and an increase in PFFA were induced by 0 to 12 hours of food deprivation. During the light period a decrease in PG occurred only from the 6th hour of fasting. A slight, progressive increase in PFFA levels was induced from 0 to 12 hours of fasting, while no significant variation of PI levels was observed. The results are discussed in terms of relationships between blood glucose, PFFA levels, and food intake in control rats over the circadian cycle.     

Loss of feeding in response to 2-deoxy-D-glucose but not insulin after zona incerta lesions in the rat

Bilateral lesions in the anterior aspects of the zona incerta of male rats reliably reduced the feeding response to systemically administered 2-deoxy-D-glucose. Insulin-induced feeding remained intact. Zona incerta lesions may interrupt central vagal projections important for the feeding response to cellular glucoprivation.     

Influence of peripheral and intracerebroventricular glucose and insulin infusions on peripheral and cerebrospinal fluid glucose and insulin levels

There is much evidence that glucose and insulin are related to the regulation of food intake and the maintenance of peripheral glucose homeostasis through actions of the central nervous system. However, evidence concerning the penetration of peripheral glucose and insulin into the cerebrospinal fluid (CSF) and the relationship between both peripheral and CSF glucose and insulin levels is still missing. In the reported experiments it is shown that insulin is present in the CSF (17 +/- 3.6 microU/ml CSF versus 44 +/- 6.0 microU/ml plasma) but that CSF insulin does not follow rises of peripheral insulin to 136 microU/ml plasma during 4.5 hours. On the other hand CSF glucose (55 +/- 3.1 mg/dl CSF) follows rises of peripheral glucose levels with a delay of about 30 min. Increase of CSF glucose by infusing glucose into the third brain ventricle elicits a prolonged decrease in peripheral glucose levels. Infusion into the third ventricle of insulin only does not change peripheral glucose. However, infusion of a combination of insulin and glucose in the third ventricle leads to a gradual increase in peripheral glucose and elicits a disappearance of the decrease in peripheral glucose after glucose only infusion into the CSF. During third ventricle infusion experiments no change in peripheral insulin could be observed. It will be argued that changes in CSF glucose and insulin contribute to maintenance of peripheral glucose homeostasis.     

Mathematical analysis of blood glucose and plasma insulin responses to insulin infusion in healthy and diabetic subjects

The blood glucose and plasma insulin responses during slow intravenous infusion of insulin in six normal and seven diabetic subjects were fitted to a previously described model utilizing four first-order rate constants for the glucose-insulin interactions. Certain lumped parameters of the model were shown to be characteristic of the subjects' responses and abnormalities. The predicted values of blood glucose and plasma insulin can be made to approximate the actual measurement in all subjects. Additional studies are proposed to delineate further the range of applicability of the model and to characterize diabetic instability.     

Effects of hypothalamic knife cuts on the ingestive responses to glucose and insulin.

Parasagittal knife cuts through the perifornical hypothalamus either medial or lateral to the fornix produced hyperphagia and obesity and altered the rat's ingestive responses to dilute glucose solutions. The lateral knife cut rats drank less dilute glucose solution under both nondeprived and food deprived conditions and displayed less of a feeding suppressive response to glucose ingestion compared to controls. The lateral cut rats were also deficient in their feeding response to insulin-induced hypoglycemia, although their altered sensitivity to glucose and insulin did not appear to be causally related. The medial knife cuts decreased the responsivity to glucose, but less so than the lateral cuts, and did not alter the ingestive response to insulin. Both the medial and lateral knife cuts did not appear to change the rat's responsivity to concentrated blucose solutions. The neuroanatomical and functional nature of the disorder responsible for these effects and its relationship to the hyper-phagia-obesity syndrome are discussed.     

不同运动强度干预2型糖尿病模型大鼠的内脂素及糖代谢变化

文题释义：运动强度：指单位时间移动的距离或速度,或肌肉单位时间所做的功。2型糖尿病：由于胰岛β细胞分泌胰岛素不足或靶细胞对胰岛素不敏感所致,亦称非胰岛素依赖型糖尿病。背景：内脂素具有胰岛素样的降糖作用,在2型糖尿病的治疗中可能有着积极的意义,不同运动强度对其的影响也不同。目的：观察6周不同强度有氧运动干预2型糖尿病大鼠糖代谢的效应及内脂素变化的特点并探讨其关系。方法：采用高脂饲料喂养并注射链脲佐菌素的方法,建立雄性SD大鼠2型糖尿病模型,将造模成功的43只大鼠随机分为糖尿病安静对照组10只,糖尿病运动Ⅰ,Ⅱ,Ⅲ组各11只。此3个运动组大鼠运动强度分别为10,15,20 m/min,运动量均为1 h/d,每周5 d,持续运动6周后采集血样,检测糖代谢相关指标、血清及内脏脂肪内脂素水平。结果与结论：①实验中3个运动组糖代谢相关指标(空腹血糖、糖化血清蛋白、胰岛素及胰岛素抵抗指数等)均出现了改善,同时糖尿病运动Ⅰ,Ⅱ组血清内脂素水平均出现非常显著性降低(P < 0.01),而糖尿病运动Ⅲ组虽有一定程度下降,但无显著性意义(P > 0.05);②糖尿病运动Ⅰ,Ⅱ,Ⅲ组内脏脂肪内脂素水平出现了显著性下降(P < 0.05),其中糖尿病运动Ⅱ内脏脂肪内脂素下降最显著(P < 0.01);③结果证实,中、低强度有氧运动能更有效改善2型糖尿病大鼠胰岛素抵抗状态,降低血糖浓度,且与内脏脂肪减少和内脂素分泌减少有关,内脂素可能起了积极的作用。ORCID: 0000-0001-9865-1802(李颖)中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

A quantitative [14C]-2-deoxy-D-glucose study of brain stem nuclei during horizontal nystagmus induced by lesioning the lateral crista ampullaris of the rat

Summary A study of the brainstem of the rat during horizontal nystagmus using the quantitative 2-deoxy-D-glucose technique reflected changes in the functional activity of cell groups based on their glucose utilization rates. Horizontal nystagmus was induced by unilateral crista ampullectomy of the horizontal canal. Comparisons of glucose utilization rates were made between experimental and control groups as well as from side to side within each group. There was a decrease of the ipsilateral medial and superior vestibular nuclei with a concomitant increase in the contralateral medial vestibular nucleus when compared to control. The medial rectus motor division of the ipsilateral oculomotor nucleus showed an increase whereas the ipsilateral abducens and the ipsilateral nucleus prepositus hypoglossi exhibited a decline in their utilization rates. The extra ocular motor nuclei responsible for the excitatory fast phase of nystagmus utilizes more substrate than those involved in the slow phase. An increase was also measured in the ipsilateral lobule of the cerebellar nodulus. The lateral reticular nucleus showed a bilateral decrease in its glucose utilization rate when compared to control.     

Effect of insulin and 2-deoxy-D-glucose on feeding and plasma glucose levels in the spiny mouse

Adult male spiny mice (Acomys cahirinus) were challenged with 2-deoxy-D-glucose (2-DG) or regular insulin, and food intake or plasma glucose concentration was measured. Mice did not increase their food intake over baseline levels following treatment with 2-DG (62.5-1000 mg/kg). In contrast, regular insulin injections (1-50 U/kg) stimulated a modest, but significant increase in feeding, which was apparent within 2 hr at a low dose of 1 U/kg. However, a marked hyper- and hypoglycemia (compared to saline controls), respectively, were induced within 30 min by 2-DG (250 and 500 mg/kg) and regular insulin (1 and 3 U/kg). Reduced glucose levels may not account for the insulin-induced hyperphagia.     

Effect of hepatic vagotomy and/or coeliac ganglionectomy on the delayed eating response to insulin and 2DG injection in rats

The eating response that occurs following recovery from the effects of insulin or 2-deoxy-D-glucose (2DG) injection was examined in rats with hepatic vagotomy and/or coeliac ganglionectomy. Rats were deprived of food and injected with either saline (1 ml/kg), regular insulin (3 U/kg) or 2DG (200 mg/kg). Plasma glucose was measured periodically over the next 6 hr and then food was returned and intakes were measured over the next 2 hr. Rats increased food intake 6–8 hr after insulin or 2DG injection compared to the saline (control) condition. Nerve section did not affect the plasma glucose or food intake responses to insulin or 2DG injection. The results indicate that the innervation of the liver via the vagus nerve or coeliac ganglion is not involved in the delayed eating response to insulin and 2DG injection.     

Effects of V.M.H. lesions on plasma insulin in the goose

The effects of bilateral electrolytic lesions of the ventromedial hypothalamus (V.M.H.) were examined in male geese. In addition to the known effects (hyperphagia, obesity and liver steatosis), V.M.H. lesions slightly increased plasma insulin level in the fasting and the fed state and largely enhanced insulin levels observed during an oral glucose and amino acid load. Therefore, V.M.H. lesions potentiate insulin release which may in turn participate in the development of hyperphagia and fattening in the goose as in mammals.     

高糖及高胰岛素对肺泡巨噬细胞氧化应激的影响

目的： 探讨高糖、高糖＋高胰岛素环境对大鼠肺泡巨噬细胞（AM）氧化应激损伤的影响。方法: 采用支气管肺泡灌洗的方法分离大鼠AM,高糖及高糖＋高胰岛素环境下培养,用卡介苗（BCG）、干扰素α-2b（IFNα-2b）或两者联合活化,检测其丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性和乳酸脱氢酶（LDH）活性。结果: BCG和IFNα-2b＋BCG活化AM时,其SOD活性均低于对照组(P<0.05),而MDA含量和LDH活性均高于对照组(P<0.05);IFNα-2b活化AM时,其MDA含量、LDH活性和SOD活性与对照组无明显差别（P>0.05）。结论: 在高糖、高糖＋高胰岛素环境可诱导AM氧化应激损伤,从而使糖尿病个体易发生肺部感染。     

Effects of amygdalar lesions on eating and drinking and saline preference in the rat

Extensive electrolytic lesions were placed bilaterally in the amygdala in albino rats. Both food and water intake relative to preoperative body weight were significantly higher in lesioned animals than in operated controls. Saline preference behavior was also investigated in a two-bottle choice situation. No difference in preference for tap water or a 1.5% NaCl solution was observed between lesioned and control animals.     

Effects of weaning on plasma levels of prolactin,oxytocin, insulin,glucagon, glucose,gastrin and somatostatin in sows

The effect of total weaning (all piglets were weaned at 35 days of lactation) and fractionated weaning (the heavier half of the litter was weaned on day 33 of lactation and the remainder 2 days later) on plasma levels of prolactin, oxytocin, insulin, glucagon, glucose, gastrin and somatostatin in primiparous sows was studied. Twelve crossbred sows were grouped into six pairs according to farrowing date and litter size. The litter of one sow in each pair was weaned in two stages (treatment), and the other was conventionally weaned (control). Blood samples were collected via a permanent jugular vein catheter every 3 hours from 9 a. m. to 9 p. m. from day 31 of lactation until the third day of final weaning. In response to total weaning (studied in the six control sows), plasma prolactin, glucagon and gastrin decreased significantly, whereas plasma insulin and somatostatin significantly increased. Basal concentrations of plasma oxytocin and glucose remained unchanged after weaning. Fractionated weaning did not result in any significant differences in the hormonal and glucose levels as compared with the total weaning. The possible role of prolactin in modulating insulin, glucagon and glucose concentrations as well as the possibility that oxytocin affects gastrin and somatostatin levels following weaning are discussed.     

Meal related effects of IV glucose,glucagon and insulin on blood glucose level: Role in glucoregulation exhibited by self-injecting rats

In previous works, it was demonstrated that rats self-injected with (IV) glucose, insulin and/or glucagon and that the self-administration pattern was related to the meal. It was suggested that the different preprandial or postprandial blood glucose level (B.G.L) determinated the meal and were dependent on it. Previously self-injected amounts of glucose, glucagon and insulin were here injected by an automatic device and their effect on B.G.L. were compared in the post and preprandial conditions. Results indicated that the effects of insulin, glucagon and glucose on B.G.L., which were different during the postprandial hyperglycemia compared to the preprandial normoglycemia, accounted for the different self-injection patterns. Furthermore successive injection of glucose and insulin or glucagon and insulin suggest that rats, by pressing alternatively two levers performed a regulatory correction of variations of their B.G.L. It is concluded that rats may learn to perform a behavioral regulation of their B.G.L. by IV self-injections of glucose and glucoregulatory hormones.