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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Procedures related to profound hypothermia and circulatory arrest have produced a great improvement in the operative results of cardiac repair in neonates and infants. As we already obtained data on the effects of these procedures on cerebral metabolism, we focussed our attention on carbohydrate metabolism to determine whether or not cardiopulmonary bypass with pulsatile flow would improve the results of bypass method for core cooling and rewarming. In 12 mongrel dogs under conditions of hypothermia, plasma levels of glucose, insulin and glucagon as well as cortisol and noradrenaline were monitored in both pulsatile and non-pulsatile bypass groups. The hyperglycemia was significantly depressed and insulin levels increased in cases of pulsatile flow. Thus, even under conditions of hypothermia, pulsatile flow results in an improvement of the blood flow in the pancreas and there is a more extensive utilization of glucose and a greater protective effect on the function of the visceral organs during bypass.
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PMID:Carbohydrate metabolism during pulsatile cardiopulmonary bypass under profound hypothermia. 634 59

To clarify the impact of hypothermia on the hormonal control of glucose metabolism, rats were rendered hypothermic (25 C) after catheterization of the portal vein. Glucose, insulin, glucagon, and catecholamine concentrations were serially monitored, and the regional blood flows were measured, allowing the estimation of hormone outputs. Hypothermia reduced the portal blood flow by 50% without changing arterial blood pressure, blood gases, or pH. Portal plasma insulin secretion dropped (0.05 +/- 0.01 vs. 0.23 +/- 0.04 mU/min), and glucagon secretion increased (0.81 +/- 0.18 vs. 0.38 +/- 0.10 ng/min). The B cell responses to glucose, arginine, and glucagon were abolished, while the A cell response to arginine was not significantly affected. Glucose intolerance was apparent after iv glucose or arginine loads. Haloperidol and to a lesser extent phentolamine suppressed the cold-induced glucagon rise. Phentolamine and to a lesser extent haloperidol alleviated the cold-induced suppression of insulin release. Propranolol, naloxone, and atropine were relatively inactive. The cold-induced glucose intolerance was not corrected by phentolamine treatment. A marked resistance to iv insulin was apparent in these rats, which is in contrast to a normal sensitivity to iv glucagon.
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PMID:Glucagon and insulin secretion and their biological activities in hypothermic rats. 643 6

The effectiveness of cold exposure on the secretion of insulin and glucagon were examined using five adult sheep. Endocrine responses were studied in a warm environment and after cold exposure (0 C) from 4-19 days. Compared to levels at room temperature, basal plasma glucose levels were elevated during cold exposure, but basal levels of plasma insulin and glucagon were unchanged. Cold exposure significantly decreased the early insulin response to a primed iv infusion of glucose. Plasma glucose and glucagon levels during glucose infusion were unaffected by cold exposure. The decrease in plasma glucose after iv insulin injection (0.2 U/kg BW) was greater during cold exposure than at room temperature. Butyrate injection (0.625 mmol/kg, iv) resulted in a significantly lower secretion of both insulin and glucagon in the cold than in the warm environment. The glucagon response to arginine infusion (0.5 g/kg over 30 min, iv) was elevated by cold exposure, whereas the insulin response to arginine tended to be reduced. Propranolol infusion (20 micrograms/kg . min, iv) caused a slight inhibition of insulin secretion in the cold environment, but did not affect glucagon levels in either the cold or warm environment. Phentolamine infusion (20 micrograms/kg . min, iv) inhibited glucagon secretion, particularly in the cold environment, and caused a markedly greater stimulation of insulin secretion in the cold. It is concluded that cold exposure insufficient to cause hypothermia decreases insulin secretion in response to a variety of stimuli. Effects of cold on glucagon secretion depend upon the stimulating agent used.
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PMID:Effects of cold exposure on insulin and glucagon secretion in sheep. 675 53

Two series of experiments with the isolated perfused rat pancreas were performed in parallel. The conditions differed only with respect to temperature, which was 37.5 degrees C in one series and 28 degrees C in the other. The lowering of the temperature decreased insulin secretion induced by glucose as well as the insulin response to tolbutamide and acetylcholine. Unlike insulin, glucagon secretion was not significantly modified by hypothermia. Our results suggest that the mechanisms involved in glucagon and insulin secretion are different.
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PMID:Different effects of hypothermia on insulin and glucagon secretion from the isolated perfused rat pancreas. 699 4

Two series of experiments were performed in parallel on the isolated perfused rat pancreas. The experimental conditions differed only as pertaining to temperature. In one series the organ and the perfusion liquid were maintained at 37.5 degrees C and in the other at 28 degrees C. The pancreases were perfused from the start of the experiments with a perfusion medium containing 8.3 mmol/l glucose. The effects of various stimulatory agents were studied (glucose 16.6 mmol/l, tolbutamide 0.4 mmol/l, acetylcholine 0.5 micromole/l, glucagon, 2.8 nmol/l, and L-isoprenaline 0.05 micromole/l). At 37.5 degrees C the insulin secretion induced by high glucose or tolbutamide, acetylcholine, and glucagon was biphasic and not statistically different. In all cases the hypothermia (28 degrees C) decreased insulin secretion. However, glucose-induced and tolbutamide-induced insulin secretion was more decreased than the secretion induced by acetylcholine and glucagon. The study of the secretion ratios obtained at 28 degrees C relative to 37.5 degrees C showed that the ratios for the glucose and tolbutamide groups were significantly lower than those obtained for acetylcholine and glucagon groups for both the first and the second phase. The ratios were not significantly different between glucose and tolbutamide on the one hand and acetylcholine and glucagon on the other hand. In all groups the ratios 28 degrees/37.5 degrees for the second phase were lower than those obtained during the first phase. L-isoprenaline induced only a weak increase in insulin secretion and this was not long lasting; this increase was not statistically different at both temperatures.
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PMID:A different action of hypothermia on insulin release from the isolated, perfused rat pancreas, depending on the stimulating agent. 700 May 86

Sixteen peptides were injected intracerebroventricularly to test their effects on rectal temperature of rabbits in a thermoneutral environment. In initial tests 5 micrograms alpha-MSH, ACTH(1--24), oxytocin, vasopressin and glucagon altered body temperature while ACTH(1--10), cholecystokinin, contraceptive tetrapeptide, gastrin, insulin, interferon, leupeptin, LHRH, panhibin (somatostatin), and proctolin did not. Bombesin also altered body temperature but in no consistent direction. In further tests on the effective peptides 1.25--5.0 micrograms alpha-MSH and ACTH(1--24) produced dose-related decreases in rectal temperature as great as 1.0 degrees C. The same doses of oxytocin and glucagon produced small, prolonged hyperthermias which did not exceed 0.4 degrees C. Vasopressin caused rapid development of small increases in rectal temperature; temperature returned to normal in 2--3 hr. The results suggest that five of the peptides tested may have roles in central mediation of normal body temperature, hypothermia, hyperthermia and fever.
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PMID:Central administration of peptides alters thermoregulation in the rabbit. 724 7

As shown in our previous study, hypothermia provokes a variety of hormonal changes including inhibition of insulin secretion and increase in blood serum glucagon level. According to Therminarias et al. the administration of exogenous insulin to dogs subjected to hypothermia causes a calorigenic effect by enhancing oxygen consumption and rising the intensity of shivering thermogenesis. The study was aimed at establishing whether exogenous insulin administered to rats subjected to brief hypothermia and having the shivering thermogenesis blocked by thiobutabarbital anesthesia can influence rectal temperature, the levels of some hormones and energy metabolism. The results obtained suggest that 1) insulin administration causes an increase in the energy charge potential (ECP) both in the liver and in skeletal muscle of the rat, indicating the domination of anabolic processes both in normothermic and hypothermic conditions, 2) there is a negative correlation between the levels of insulin and free fatty acids and the activity of isocitric dehydrogenase in rat liver mitochondria, and 3) the administration of insulin at a dose provoking metabolic response both in normothermic and hypothermic conditions was ineffective in provoking temperature response, indicating the existence of a functional dissociation between the various effects of the same dose of exogenous insulin.
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PMID:[Effect of insulin on temperature and metabolic responses in rats during normothermia and hypothermia]. 805 Mar 87

The aim of the study was to estimate the effect of hypothermia on (125J)-iodoinsulin binding to liver plasma membranes. Rat liver membranes were prepared from control, normothermic rats (Tr = 35.6 +/- 0.3 degrees C) and hypothermic rats (Tr = 26.5 +/- 0.9 degrees C) and purified according to Havrankowa. In addition, serum insulin and glucagon levels by means of RIA and glucose concentration using the glucose oxidase method were measured. Scatchard analysis was used to determine the kinetic parameters of the hormone receptor interaction. The data showed no significant differences in the affinity of the binding sites but indicated a decrease in receptor concentrations in liver plasma membranes from hypothermic rats. In contrast to changes in serum insulin level which was decreased by about 50% in hypothermic rats blood glucose concentrations did not significantly differ between the hypothermic and normothermic ones. Our results show that in hypothermic rats the hormonal adaptation operates on the level of the number of liver receptors whereas the insulin receptor affinity remains unaffected.
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PMID:Effect of hypothermia on the insulin--receptor interaction in liver plasma membranes. 812 87

Infants undergoing open-heart surgery with hypothermic cardiopulmonary bypass experience markedly elevated lactate and glucose levels. Reports in infants less than 10 kg show the elevated lactate to be progressive during the operative period. The pathogenesis of the hyperglycemia is not clear but may be caused by excess glucose administration, inadequate insulin response, or glucose regulatory hormone levels of glucagon, cortisol, and growth hormone. The purpose of this study is to confirm these findings and to investigate their pathogenesis. Serial blood samples were taken preoperatively, intraoperatively, and postoperatively during hypothermic cardiopulmonary bypass in nine infants of less than 10 kg. Samples were analyzed for levels of lactate, glucose, and regulatory hormones insulin, growth hormone, glucagon, and cortisol. Our study did not show a progressive accumulation of lactate. The elevated lactate level appears to come from the pump prime solution. The hyperglycemia is also from the pump prime solution, and there do not appear to be elevated levels of regulatory hormones intraoperatively. Insulin response during hypothermia is blunted; however, on rewarming the patient in the immediate postoperative period, a brisk insulin response is seen. The changes in levels of lactate and glucose and the regulatory hormones return to baseline at 24 hours with no further significant changes in the next 48 hours.
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PMID:Lactic acid changes during and after hypothermic cardiopulmonary bypass in infants. 847 97

Nesidioblastosis associated with progressive weight loss and hyperglycemia was diagnosed in two mid-adult, wild-caught, male squirrel monkeys (Saimiri sciureus). Hyperglycemia, glucosuria, and abnormal glucose tolerance test results were found when the monkeys were presented for clinical evaluation for chronic weight loss, episodic dehydration, hypothermia, and lethargy. Immunohistochemical studies of the pancreatic tissue demonstrated that the proliferating endocrine cells stained predominantly glucagon-positive in the most severely affected monkey.
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PMID:Nesidioblastosis associated with hyperglycemia in two squirrel monkeys (Saimiri sciureus). 902 1


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