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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Preformed arterial collaterals are critical to renal parenchymal survival after acute total renal artery occlusion. This study was designed to delineate and quantify preformed collaterals and assess their response to vasodilators. A Swan-Ganz catheter induced a sudden, total occlusion of a renal artery sufficient to reduce distal arterial pressure to near zero and prevent perfusion through the renal artery. Arteriography assessed the effectiveness of the occlusion and delineated the collateral arterial pathways. Strontium, cerium-, and chromium-labeled microspheres measured renal blood flow and cardiac output 1, 60, and 120 minutes after occlusion. In two additional series of experiments either contralateral nephrectomy was performed 5 to 8 days before the study, or dibenzylene, dopamine, or glucagon were administered in an attempt to increase blood flow through the collaterals. Collateral renal blood flow was demonstrated in all dogs. Mean blood flow to the occluded kidneys ranged from 0.13 +/- 0.05 cm3/minute/g to 0.22 +/- 0.08 cm3/minute/g, about 5% of control values. Neither prior contralateral nephrectomy nor vasodilator agents increased the flow to the obstructed kidneys. In the dogs with intact contralateral kidneys, however, there was a progressive decrease in cardiac output during the experiment, which was not found in uninephrectomized animals. We concluded that preformed arterial channels are available to maintain a small, but probably critical level of perfusion following sudden total occlusion of the renal artery. Neither hypertrophy due to prior contralateral nephrectomy nor active vasodilators modify flow through the preformed channels. It is likely that total renal ischemia provides a maximal stimulus for vasodilatation. The pattern of hind limb collaterals differed strikingly from those of the kidney, with maintenance of a greater portion of a normal flow and rapid increase in flow within 1 hour after femoral artery occlusion. Thus, data concerning collateral circulation cannot be generalized from one vascular bed to another even in the same species.
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PMID:Renal collateral blood supply after acute unilateral renal artery occlusion. 120 8

Lithuania's environment is heavily polluted as a result of domestic and transboundary contamination. The main ecological problems are related to atmospheric pollution; water contamination; soil, water, and forest acidification; nitrogen-compounds overload of soil, water, and food; and contamination with agricultural chemicals and heavy metals. The increased environmental distress is a menace to public health in Lithuania. Experimental studies need to be designed and used to ascertain the effects of environmental distress on the gastrointestinal tract epithelial barrier. Our electronmicroscopic and immunohistochemical study of human gastrointestinal endocrine cells revealed changes in the amount of secretory material and intracytoplasmic vacuolization after exposure to the environmental chemicals such as hexavalent chromium and the herbicide Saprol. The most affected were the EC (serotonin, motilin, substance P), D (somatostatin), A (glucagon), B (insulin), and mast (histamine, serotonin, heparin) cells. These results provide ultrastructural evidence of digestive tract epithelial barrier reaction as an expression of environmental distress signals of the organism.
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PMID:Environmental monitoring in Lithuania. Environmental distress signals: gastrointestinal epithelial barrier after exposure to chemical agents. 146 10

The effects of low-chromium diets containing chromium in the lowest quartile of normal intake on glucose tolerance and related variables in 11 females and 6 male subjects were evaluated. Subjects with glucose concentration greater than 5.56 mmol/L but less than 11.1 mmol/L 90 min after an oral-glucose challenge were designated as the hyperglycemic group and the remainder, the control group. Glucose tolerance and circulating insulin and glucagon of the hyperglycemic group all improved during chromium supplementation (200 micrograms/d) whereas those of the control group were unchanged. Glucose and insulin concentrations 60 min after the oral-glucose challenge and the sum of the 0-90 min and 0-240 min glucose values were all significantly lower after chromium supplementation in the hyperglycemic group. These data demonstrate that consumption of diets in the lowest 25% of normal chromium intake lead to detrimental effects on glucose tolerance, insulin, and glucagon in subjects with mildly impaired glucose tolerance.
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PMID:Supplemental-chromium effects on glucose, insulin, glucagon, and urinary chromium losses in subjects consuming controlled low-chromium diets. 195 Nov 65

Depressed cell-mediated and humoral immune functions have been reported to occur following severe thermal and traumatic injury. In this study we have questioned whether another immune function, natural killing (NK), is also disturbed in these injured patients. Twenty-two thermally injured patients with burns ranging from 5 to 75% of the total body surface area and 15 traumatically injured patients with injury severity scores ranging from 9 to 56 were followed postinjury and compared to 29 age-matched controls. NK activity was measured as the percentage cytotoxicity in chromium-51 release assays with K562 target cells. The more severely burned patients had significantly depressed NK activity for the 40-day period following injury that remained reduced for the duration of the study. Patients with lesser burns had reduced NK-cell function for the initial 10-day period postburn that returned slowly to the normal range. Traumatically injured patients had depressed NK-cell function during the 3- to 6-day period postinjury. The percentage of cells bearing phenotypic markers for the groups in which NK cells are found was either normal or elevated in these patients. A correlation was found between NK activity and interleukin 2 generation by mononuclear cells from these patients. In order to investigate the mechanism of NK suppression in these patients, NK-cell function was studied following the infusion of cortisol, epinephrine, and glucagon into volunteer subjects in amounts known to reproduce serum levels seen following injury of moderate severity. NK-cell function was reduced an average of 66% following infusion, suggesting that the inhibition of NK-cell function seen in patients may be mediated by the stress response to injury.
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PMID:Suppression of natural killer-cell function in humans following thermal and traumatic injury. 348 53

Diabetes mellitus has been shown to develop as a consequence of chromium (Cr) deficiency in experimental animals and in humans sustained by prolonged total parenteral nutrition. Prior limited trials in humans had indicated that Cr supplements, in either inorganic or organic form, may improve carbohydrate utilization. We report here a clinical double-blind, random crossover trial of inorganic Cr trichloride, a brewer's yeast that contained Cr as glucose tolerance factor (GTF), a brewer's yeast extract without GTF, and a placebo. Forty-three outpatient diabetic men received three of these supplements for 4 mo each. Subgroups included 21 ketosis-prone men; 7 ketosis-resistant, nonobese men; and 15 ketosis-resistant obese men. Chromium levels were followed pre- and posttreatment in hair, red blood cells, plasma, and urine. Response of carbohydrate metabolism to treatment was assessed in terms of change in insulin requirements, fasting plasma glucose, plasma cholesterol, and triglycerides, as well as change in plasma glucose, glucagon, and insulin or C-peptide levels in response to a standard meal. In some men, these parameters were also measured after i.v. tolbutamide. Both the inorganic and organic oral Cr supplements increased measurable body pools of Cr in hair and red blood cells by about 25%. However, fasting plasma glucose and lipids and the glucose response to either the standard meal or to tolbutamide were not significantly altered by any of the treatments. Despite this lack of effect on carbohydrate levels, the ketosis-resistant subgroups demonstrated a significant increase in postprandial insulin after treatment with the brewer's yeast that contained GTF.
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PMID:Effects of chromium and yeast supplements on carbohydrate and lipid metabolism in diabetic men. 635 8

Chromium is involved in normal glucose metabolism. To test whether chromium is also associated with the exercise-induced increases in glucose utilization, urinary chromium excretion, serum glucose, insulin, and glucagon of nine male runners (23-46 yr) were evaluated. Blood samples were taken prior to, immediately following, and 2 h after a strenuous 6-mile run. Urine samples were also taken at these times, and total daily urine collections were made the day of the run and the following day. Mean serum glucose for all runners immediately after running was 185 +/- 19 mg/dl compared with 90 +/- 1 mg/dl (mean +/- SE) prior to running. Mean serum glucagon immediately after running was significantly elevated compared with that observed prior to or 2 h after running; serum insulin levels were not altered significantly. Mean urinary chromium concentration was increased nearly five-fold 2 h after running; similar results were obtained when chromium concentration was expressed per mg of creatinine. Total daily urinary Cr excretion was approximately two times higher the day of running compared with the following nonrun day. Daily urinary excretion of sodium, potassium, and calcium were measured to determine if exercise had a general nonspecific effect on renal function; daily urinary excretion of these was not changed by exercise. These data demonstrate that accompanying the exercise-induced changes associated with increased glucose utilization, there is a significant increase in chromium excretion.
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PMID:Effect of exercise (running) on serum glucose, insulin, glucagon, and chromium excretion. 675 38

Twenty-four Suffolk lambs (average BW 38 +/- 2.7 kg; 16 ewes and 8 wethers) were fed either a corn-cottonseed hull-based control diet (CON) or CON plus 250 ppb of Cr as chromium tripicolinate (CrPic). Lambs were penned in groups of three and ADG and DMI were measured through d 85 of the experiment. Jugular blood samples were obtained during wk 2, 7, and 11. An i.v. glucose tolerance test (IVGTT; 500 mg of glucose/kg BW) and an i.v. insulin challenge test (IVICT; .1 IU of ovine insulin/kg BW) were performed during wk 2 and 10 of the trial. This was followed by a N balance trial during wk 3 and 11. Wethers were slaughtered at the end of the experiment and carcass characteristics determined. No differences (P > .10) were observed between dietary treatments in DMI, ADG, or N balance; however, the CrPic-fed wethers had 18% less fat over the 10th rib (P = .082) and a lower yield grade (P = .014). Plasma NEFA was lower throughout the trial (P < .03) and cholesterol was 17% lower during wk 2 (P < .02) in lambs fed CrPic. There were no differences due to diet (P > .10) in plasma concentrations of urea N, glucose, albumin, total protein, insulin, glucagon, triiodothyronine, or thyroxine. Glucose clearance rate and half-life during the IVGTT and IVICT did not differ (P > .10) between CON and CrPic groups; however, during the IVGTT on wk 2, plasma insulin was elevated (P < .05) and glucose reduced (P = .067) in the lambs fed CrPic. Supplemental CrPic seems to influence metabolic measurements that may affect performance of growing lambs.
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PMID:Influence of chromium tripicolinate on glucose metabolism and nutrient partitioning in growing lambs. 858 60

The purpose of this study was to determine if diet or various metabolites alter chromium (Cr) uptake and distribution in rats. Radioactively labeled Cr was detected within 15 min of oral administration to rats, and the total amount retained remained relatively constant from 1 to 24 h. Dietary Cr intake did not alter Cr retention or distribution. The majority of the Cr was retained in the carcass. However, when the amount of labeled Cr was expressed per gram of tissue, the highest amounts of Cr were found in the kidneys, spleen, and pancreas. Pharmacological doses of insulin, epinephrine, glucagon, and dibutyryladenosine-3'-5'cyclic monophosphate, prostaglandins A1, A2, B1, B2, E1, E2, F1 alpha, and F2 alpha did not significantly influence Cr retention. Glucose, sucrose, nicotinic acid, glutathione, and other metabolites administered orally in conjunction with labeled Cr also did not significantly alter Cr retention. These data indicate that most nutrients and metabolites do not alter Cr retention and distribution. The regulation of Cr homeostasis appears to be at the level of excretion.
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PMID:Dietary and metabolite effects on trivalent chromium retention and distribution in rats. 860 85

Increased pancreatic beta-cell secretory activity usually is associated with decreased alpha-cell activity; stimulated beta-cells release gamma-aminobutyric acid, which hyperpolarizes alpha-cells, inhibiting glucagon release. Thus, insulin secretion and glucagon secretion are usually inversely coupled. This suggests that chromium and other insulin-sensitizing modalities, by down-regulating beta-cell activity, may increase glucagon secretion. Such an effect might play a role in the documented therapeutic activity of supplemental chromium and biguanides in reactive hypoglycemia, and might also be of benefit to dieters.
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PMID:Chromium and other insulin sensitizers may enhance glucagon secretion: implications for hypoglycemia and weight control. 869 48

Two studies were conducted to evaluate the effects of Cr supplementation on blood metabolite and hormonal responses of Holstein cows to glucose challenges during late pregnancy and early lactation and to propionate challenges during early lactation. Eight multiparous and 4 primiparous cows (Experiment 1) and 12 primiparous cows (Experiment 2) were assigned to one of two treatments: control and 0.5 ppm of supplemental Cr. The glucose challenges were performed at 2 wk prepartum and at 2 wk postpartum, and the propionate challenges were conducted at wk 2 and 6 postpartum. During glucose tolerance tests, Cr supplementation reduced the ratio of insulin to glucose and reduced plasma concentrations of insulin and triglycerides of primiparous cows during the prepartum period. Chromium supplementation decreased plasma Cr of primiparous cows following glucose challenge. With supplemental Cr, insulin sensitivity was reduced postpartum, particularly for primiparous cows, but insulin sensitivity was increased prepartum. Results of this study suggested that primiparous cows experienced Cr deficiency during late pregnancy and possibly during early lactation. Following propionate infusion, Cr supplementation increased the serum glucose peak, increased the area under the response curve for serum glucose, and tended to increase IGF-I concentrations. Chromium supplementation tended to reduce the ratio of insulin to glucagon. Supplementation might have enhanced gluconeogenesis or glycogenolysis. Supplemental Cr also resulted in reduced variability of most parameters during both experiments.
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PMID:Metabolite and hormonal responses to glucose or propionate infusions in periparturient dairy cows supplemented with chromium. 888 Apr 68


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