Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(i) Hepatocytes isolated from adult rats were cultured for 2 to 3 weeks on collagen in a modified, serum-free Waymouth medium containing fatty acids and varying concentrations of glucocorticoid, insulin and glucagon. (ii) In the presence of all three hormones, it was possible to maintain the content of DNA, the activity of glucokinase, pyruvate kinase, hexokinase and lactate dehydrogenase at initial levels for 2 to 3 weeks. The activity of glucokinase and pyruvate kinase was affected by the concentration of insulin. (iii) The activity of alcohol dehydrogenase was stable for 3 days and declined to about 25% of the initial level after 2 weeks of culture, irrespective of the presence of hormones. (iv) Maintenance of albumin secretion was dependent on the presence of glucocorticoid, and glucocorticoid and insulin showed an additive or, at some time points, a synergistic effect on its secretion. (v) The content of cytochrome P-450 could be kept at 65% of the initial level, provided that a relatively high concentration of dexamethasone was present (10(-6) M). (vi) In the absence of hormones, urea synthesis was 70% of initial levels throughout the experimental period. With insulin and glucocorticoid present, a high concentration of glucagon (10(-8) M) was required to maintain the synthesis of urea at this level. (vii) It is concluded that hepatocyte cultures as described in the present study may be a useful, well-defined system for long-term metabolic, pharmacologic and toxicologic studies.
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PMID:Long-term culture of hepatocytes: effect of hormones on enzyme activities and metabolic capacity. 327 89

Acute administration of ethanol increases portal blood flow by 40-60%. This increase in blood flow compensates for the increase in O2 consumption that follows alcohol intake and may play a protective role against hypoxic hepatocellular necrosis. We have investigated the mechanism of this hemodynamic effect of ethanol in the rat using the labeled microsphere technique. We ruled out a direct role of systemic glucagon and of acetaldehyde in mediating the increase in portal flow. However, the increase in flow is maximal at a blood ethanol concentration of 3.5 mM, corresponding to that required to achieve the Vmax of alcohol dehydrogenase, and is suppressed by 4-methylpyrazole, an inhibitor of alcohol dehydrogenase. Alcohol ingestion results in zonal liver hypoxia and in increases in acetate, both of which have been shown to increase the levels of adenosine, a potent vasodilator, in blood and tissues. Ethanol produces a 400% increase in arterial adenosine. Adenosine infusion leads to a dose-dependent increase in portal blood flow of up to 100%, an effect that is suppressed by administration of 8-phenyltheophylline, an antagonist of adenosine at A1 and A2 receptors. Similarly, the ethanol-induced increase in portal blood flow is fully suppressed by 8-phenyltheophylline. In conclusion, adenosine appears to play an important role in the mechanism by which ethanol increases portal blood flow.
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PMID:New insights on the mechanism of the alcohol-induced increase in portal blood flow. 328 79

Rat hepatocytes were cultured in a modified HI-WO/BA medium for 13 days, and the combined effect of dexamethasone, 10(-7) M, insulin, 10(-8) M, and glucagon, 10(-9) M on the DNA-content, and on the activity of several enzymes, the secretion of albumin and the rate of ethanol oxidation was investigated. The effect of ethanol on these parameters was also studied. All parameters measured declined with time in the hormone-free cultures. In hormone-supplemented cultures, the DNA-content, the activity of glucokinase, pyruvate kinase, hexokinase and lactate dehydrogenase and the secretion of albumin was maintained at reasonable levels throughout the 13 days, whereas both the activity of alcohol dehydrogenase and the rate of ethanol oxidation fell significantly, although less than in hormone-free cultures. Addition of 50 mM ethanol to the hormone-supplemented culture medium caused a ca. 20% fall in the activity of glucokinase and pyruvate kinase and a 20% increase in alcohol dehydrogenase activity. No effect of ethanol was observed on the activity of hexokinase and lactate dehydrogenase or on the secretion of albumin.
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PMID:Long-term culture of hepatocytes: ethanol oxidation and effect of ethanol on enzyme activities and albumin secretion. 332 6

The stress response in humans commonly includes elevations in plasma concentrations of glucocorticoids, catecholamines, glucagon, growth hormone, aldosterone, and renin, resulting in alterations in the metabolism of glucose and other energy substrates, and in increased sodium and water retention. In severe illness, triiodothyronine and sometimes thyroxine are decreased without evidence of clinical hypothyroidism. Antidiuretic hormone may be elevated in bacterial meningitis and other central nervous system disorders, as well as in acute asthma, chronic ventilator therapy, pneumothorax, atelectasis, and postoperatively. Increased ADH concentration can lead to significant hypoosmolality and hyponatremia with adverse effects on the patient. In the setting of severe intracerebral insults, ADH may be inappropriately low, resulting in diabetes insipidus. Insulin concentrations may be inappropriately low for serum glucose concentration, or insulin may have diminished receptor responsiveness in seriously stressed patients. Either situation leads to hyperglycemia. Disturbances in calcium, phosphorus, and magnesium homeostasis may occur relatively frequently in the critically ill patient in response to therapeutic interventions, or illness-induced altered metabolism. It is not always clear when an altered metabolic or hormonal state is an appropriate response to a stress, or represents decompensation of the body's mechanisms for coping with that stress. It is important, however to recognize the common responses of the organism to severe illness, and to monitor for treatable abnormalities which occur.
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PMID:Endocrine manifestations of critical illness in the child. 354 20

The effect of glucagon on the activity of alcohol dehydrogenase in rat hepatocyte culture was determined. Glucagon concentrations of 0.1 nM enhanced, whereas concentrations greater than 1 nM decreased, alcohol dehydrogenase. These effects became apparent after exposure of the cultures to glucagon for 4 or more days. The presence of corticosterone (1 microM) prevented the enhancing effect of 0.1 nM glucagon on alcohol dehydrogenase activity. The changes in alcohol dehydrogenase caused by glucagon were associated with parallel changes in the rate of ethanol elimination. Alcohol dehydrogenase appears to be rate-limiting for ethanol oxidation, as uncoupling of oxidative phosphorylation did not modify the rate of ethanol elimination. These studies suggest a physiologic role of glucagon in enhancing liver alcohol dehydrogenase activity, whereas higher pharmacologic concentrations of glucagon have an opposite, depressant effect.
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PMID:Effect of glucagon on alcohol dehydrogenase activity in rat hepatocyte culture. 375 18

The aging kidney suffers reduction both in mass and in glomerular filtration rate. These changes may be totally or partially due to atherosclerosis and hypertension, which reduce renal blood flow. Superimposed on these processes, and perhaps responsible for primary loss of renal mass irrespective of renal vascular disease, is glomerular damage and involution that is a consequence of adaptive increases in glomerular perfusion pressure that occurs as the number of nephrons decline with age. The data available at this time do not allow us to distinguish between these two potential mechanisms of renal senescence. The decline in GFR is in turn responsible for reduced renal acidification and the reduced renal clearance of drugs that are normally removed by the kidney. Certain renal functions, however, are depressed to a greater extent than is GFR. Both the ability to maximally dilute the urine and to maximally concentrate it are controlled by serum ADH concentrations and by the action of that hormone on the collecting duct. Aged rats do not maximally secrete ADH under conditions of dehydration and the effect of ADH on the kidney is also attenuated. Elderly humans also cannot maximally suppress ADH secretion when serum osmolality is reduced. Likewise, the renin-angiotensin-aldosterone axis is poorly responsive to volume depletion in aging subjects. As a result, elderly individuals cannot maximally retain sodium under conditions of plasma volume contraction out of proportion to reduction in GFR. The kidney is the site of vitamin D1 hydroxylation. Hydroxylation of vitamin D is reduced out of proportion to any reduction in GFR in the rat. There are no data as yet available on the effect of aging and the production of erythropoietin, a principal regulator of red blood cell mass. Neither are there data available on changes that might occur with advancing age in the ability of the aging kidney to metabolize various hormones, such as parathyroid hormone, glucagon, and insulin. The mechanisms and the full biochemical and physiologic consequences of renal senescence remain to be fully elucidated.
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PMID:The aging kidney. 391

In this study we report the effect on splanchnic hemodynamics of acute oral ethanol at doses ranging from 0.25 to 4.0 g/kg body wt. Flows were determined by use of a radioactive microsphere technique. Ethanol was found to increase portal blood flow by 23-57%. In awake rats this increase reached a plateau at the 0.5 g/kg dose. In ketamine-anesthetized rats, the increase was observed only at doses of 3.0 g/kg or more, with the response at doses of 0.5, 1.0, and 2.0 g/kg being suppressed by ketamine. Inhibition of alcohol dehydrogenase by intra-arterial administration of 4-methylpyrazole resulted in suppression of the liver blood flow increase after ethanol was administered to awake animals. Ethanol in the range of doses studied did not result in changes in blood glucagon levels. Rats fed ethanol-containing diets for 4 wk and withdrawn for 18 h had the same response to acute oral ethanol as did naive rats. It is suggested that ethanol metabolism mediates the effects of ethanol on splanchnic blood flow. An increase in splanchnic blood flow when concurrent with an increase in liver O2 consumption induced by ethanol might protect the liver from hypoxic damage.
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PMID:Role of ethanol metabolism in the ethanol-induced increase in splanchnic circulation. 396 96

To elucidate the ectopic hormonal pattern in patients with small cell carcinoma of the lung, plasma ACTH, serum calcitonin, serum gastrin, plasma glucagon, serum insulin, plasma secretin, plasma VIP, serum growth hormone, serum hCG/LH, the total of serum hCG and hCG-beta-subunit,serum alpha-subunit, serum human placental lactogen, urine ADH, urine 5-HIAA, urine VMA, urine HVA, and urine hCG-LH were measured prior to therapy in 75 patients. Twenty-two patients (29%) had elevated plasma ACTH, and 18 of these had concomitant increased values of corticosteroid in a 24-hour urine sample. Forty-eight patients (64%) were found to have elevated serum calcitonin, and one-third of the patients were diagnosed as having the ectopic ADH syndrome. Serum gastrin concentrations were increased in 20% of the patients, but the elevations were marginal in almost all cases. None of the remaining substances was found to be significantly elevated. Concentrations of plasma ACTH, serum calcitonin, and urine ADH were not found to be correlated with the stage of the disease, and no correlation of these substances with the histological subtypes of small cell carcinoma was disclosed.
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PMID:Hormonal polypeptides and amine metabolites in small cell carcinoma of the lung, with special reference to stage and subtypes. 624 82

The effects of Tramadol-N2O-anaesthesia on the per- and postoperative change in blood concentrations of cortisol, prolactin, thyroxine, triiodothyronine, cyclic AMP, glucagon, antidiuretic hormone, PTH-peptide (44-68), glucose, lactate, pyruvate and free fatty acids (FFA) were investigated in connection with elective orthopaedic surgery. Anaesthesia in man with Tramadol and nitrous oxide were found to be associated with a significant elevation of plasma cortisol and plasma prolactin in man. However, cortisol secretion during anaesthesia is associated with an inhibition in T4-T3 conversion. No significant alterations in plasma glucagon concentrations were observed. Generally, surgical trauma induced a significant increase in plasma cyclic AMP with intraoperative levels between 26.4 and 34.3 pmol/ml. At the end of surgery a significant fall in plasma PTH-peptide (44-68) occurred. There was also a significant change in plasma ADH levels following induction of anaesthesia. During surgery we found plasma ADH levels up to 56 pg/ml. In addition stress and surgical trauma increased blood glucose and FFA while plasma pyruvate and plasma lactate nearly remained unchanged. The data would suggest that the non-specific stress response attributed to anaesthesia may in fact be reflecting a response to relatively light anaesthesia.
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PMID:[Endocrine reaction pattern in the course of a one-phase tramadol-N2O combination anesthesia]. 629 29

The effects of glucagon and PTH on renal tubular electrolyte handling were studied in anesthetized, thyroparathyroidectomized Brattleboro rats infused with somatostatin. Fractional excretion of Ca and Mg was significantly lower during infusion of both hormones. Micropunctures of same nephrons localized the bulk of the increase in reabsorption in Henle's loop, where both hormones significantly enhanced the reabsorptive capacities for Ca, Mg, and K. Beyond the early distal tubule, Ca and Mg reabsorption was significantly greater during glucagon infusion and Ca reabsorption was significantly greater during PTH infusion. Cyclic adenosine monophosphate at a plasma concentration of 10(-6) M did not reproduce the effects of either glucagon or PTH. These results are similar to the findings reported for the effects of ADH and calcitonin on Ca, Mg, and K tubular handling, but different as far as Na and Cl are concerned, since their loop reabsorption was not significantly altered by glucagon and PTH. The data obtained here for glucagon and PTH, together with those for ADH and calcitonin, support the hypothesis that these four hormones exert similar effects in the thick ascending limb.
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PMID:PTH-like glucagon stimulation of Ca and Mg reabsorption in Henle's loop of the rat. 669 22


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