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Biomedical subjects

R L Prior

Publications and source records attributed to R L Prior.

At least 91 records · Page 5Linked to original sources
PubMed1979

Xylazine-induced hyperglycemia in beef cattle.

Intravenous administration of xylazine to beef cattle (10 animals, 0.2 mg/kg of body weight) resulted in rapid onset (less than 15 minutes) of hyperglycemia. Plasma glucose values increased to 195 +/- 15 mg/dl and 305 +/- 10 mg/dl at 15 minutes and 3 hours, respectively. Concomitantly, plasma insulin concentrations dropped from 23 +/- 2 microU/ml before xylazine to 5.8 +/- 0.7 microU/ml and 2.4 +/- 0.3 microU/ml at 15 minutes and 3 hours, respectively. Parallel decreases (20%) were observed for percentage of hemoglobin, red blood cell number, and packed cell volume. Plasma urea nitrogen was significantly (P less than 0.01) incrased within 3 hours of xylazine administration (6.7 +/- 0.9 mg/dl vs 11.4 +/- 0.7 mg/dl). Marked changes in concentrations of plasma-free fatty acids were not observed. Alternative means of anesthesia must be considered in those instances in which biopsy material is to be used for studies of carbohydrate metabolism in vitro.

Animals↗
PubMed1977

Gluconeogenesis from alanine in vivo by the ovine fetus and lamb.

Gluconeogenesis from alanine was determined with an intravenous infusion of [U-14C]alanine and [6-3H]glucose or [U-14C]glucose in five fetal lambs (3.6 +/- 0.1 kg; 127 days of gestation) and four growing ewe lambs (37 +/- 2 kg). Conversion of alanine to glucose (mmol/h) was 0.40 +/- 0.12 and 0.51 +/- 0.10 and accounted for 7.3 and 25.6% of the alanine turnover in fetal and growing lambs, respectively. Alanine contributed 2.3 and 1.1% of the glucose turnover and 22.3 and 1.1% of the lactate turnover in fetal and growing lambs, respectively. Lactate contributed 19.5% of the glucose turnover in growing lambs, and glucose synthesis from lactate accounted for 24.7% of the lactate turnover. Glucose turnover (mmol/h) was 10.2 and 25.1 in fetal and growing lambs, respectively. Results from these studies have shown that the fetal lamb at 127 days of gestation has a high rate of alanine turnover and conversion to glucose when compared with that of the growing lamb on a high plane of nutrition.

Alanine↗
PubMed1975

Urea, citrate and orotate excretion in growing rats fed amino acid-deficient diets.

Male, weanling rats were fed a control purified amino acid diet or the same diet with lysine, phenylalanine, tryptophan, valine, or arginine omitted singly, or both arginine and lysine omitted. Blood urea reached three to four times that of control levels with all deficient diets. Urea excretion increased almost linearly with time during the first 3 days of amino acid deficiency. Rates of urea excretion on day 3 in decreasing order for various deficiencies were as follows: lysine and arginine combined are more than lysine is more than tryptophan equals valine is more that phenylalanine equals arginine. Urinary citrate was 26 and 21.8 times that of control values without arginine and 11.4 and 6.2 times that of control values without lysine on days 2 and 3, respectively. By day 8 citrate excretion had returned to control levels without lysine but not without arginine. Citrate excretion was unchanged with other deficiencies. Orotic acid excretion increased markedly only without arginine and slightly without tryptopahn. A deficiency of arginine and lysine increased urea and citrate excretions to a greater extent than either deficiency alone. Two injections of arginine or homoarginine (0.50 mmole/injection) given at 12-hour intervals to rats fed no lysine and arginine for 3 days decreased citrate excretion immediatedly and on the following day. Urea excretion decreased with injected homoarginine, but not with arginine. Orotic acid excretion increased more than four times on the day of homoarginine injection compared with that of the preceding day. Arginine injection returned orotic acid excretion to nearly control levels within 24 hours. Urea degradation in the gastrointestinal tract was increased in animals fed amino acid-deficient diets.

Amino Acids, Essential↗
PubMed1975

Citric, orotic, and other organic acids in rats injected with active or inactive urease.

Male rats were fed laboratory chow or a purified L-amino acid diet containing 11.2 or 5.6 g arginine/kg. Hyperammonemia was produced by injection of crystalline jackbean urease. Control animals were injected with saline or inactivated urease. Rats injected with 55 U urease activity/kg body wt (an LD50 dose) exhibited acute signs of hyperammonemia and elevated orotate and citrate in their urine. Plasma glucose, lactate, citrate, and alpha-ketoglutarate concentrations were also markedly elevated. Three injections of active urease (10 U/kg body wt) given at intervals of about 10 h produced hyperammonemia, which persisted for 25 h after the first injection. Blood glucose and ammonia concentrations were increased 2.6- and 22-fold, respectively, when compared with controls. Total urinary citrate excretion for 25 h was 371 mueq for active urease-injected rats compared with 62 mueq for rats injected with inactivated urease. Rats fed a purified amino acid diet containing 5.6 g arginine/kg excreted greater quantities of urea, citrate, and orotic acid than rats fed 11.2 g arginine/kg of diet. Injection of active urease increased citrate excretion by rats fed either concentration of dietary arginine. Changes produced with active urease were not observed if inactivated urease was injected.

Acetates↗
PubMed1975

Arginine deficiency and orotic aciduria in mammals.

Dietary arginine deficiency in rats causes significant increases in urinary excretion of urea, citric acid and orotic acid independently of feed intake. Urea excretion during arginine deficiency depends upon the diet, sex, age, and species. Thus urea excretion has limitations as an indicator of arginine availability. Although elevated urinary citric acid during arginine deficiency is more consistently observed, it may be influenced by citric acid in natural dietary ingredients. Orotic acid excretion, however, appears to be a reliable indicator of available dietary arginine based upon studies in rats, mice, hamsters, guinea pigs, rabbits, and dogs.

Animals↗