Valine oxidation: the synthesis and evaluation of L-[3-3H]valine as a tracer in vivo.

The suitability of L-[3-3H]valine for measuring valine oxidation was studied by comparing its oxidation rate with that of L-[1-14C]valine in rats and pigs. L-[3-3H]valine was synthesized by removal of the tritium on carbon-2 of L-[2,3-3H]valine by acetylation. The acetyl group was removed enzymatically using pig renal acylase 1 (EC 3.

Quantitative partition of threonine oxidation in pigs: effect of dietary threonine.

Kinetic aspects of threonine (Thr) metabolism were examined in eight pigs fed hourly with a diet containing either 0.68% (LT group) or 0.81% (HT group) of Thr (wt/wt), corresponding to 10 and 30% Thr excess, respectively, compared with an "ideal" diet.

Urea synthesis and leucine turnover in growing pigs: changes during 2 d following the addition of carbohydrate or fat to the diet.

1. Studies have been made of the time-sequence of protein metabolic and hormonal changes following an abrupt increase in carbohydrate or fat intake. [3H]leucine and [14C]urea were infused for 72 h, via the aorta, into fourteen female pigs (30-38 kg body-weight).

Effects of the amount and quality of dietary protein on nitrogen metabolism and protein turnover of pigs.

1. The interrelation between protein accretion and whole-body protein turnover were studied by varying the quantity and quality of protein given to growing pigs. 2.

Effects of the amount and quality of dietary protein on nitrogen metabolism and heat production in growing pigs.

1. Eight pigs with a mean weight of 48 kg were given, at a constant daily rate, diets of low (0.15) or high (0.

Protein synthesis and retention in some tissues of the young pig as influenced by dietary protein intake after early-weaning. Possible connection to the energy metabolism.

Changes in fractional protein synthesis rates (FSR) of 4 tissues (muscle, liver, intestine and bone) were assessed in 2 groups of young pigs from weaning, 10 days postpartum, to one week later, after feeding equal amounts of dry diets at 2 levels of protein (15 and 30%). In the meantime, protein and energy balance measurements were performed on the whole body partitioned into 4 components (carcass, liver, digestive organs, other organs + blood). Whole body energy balances were strongly negative in both groups as a result of low metabolisable energy (ME) intakes and fat mobilization.

Protein turnover in growing pigs. Effects of age and food intake.

1. Measurements were made of the nitrogen and energy balances of pigs of 30, 60 and 90 kg given a conventional diet at various daily rates. 2.

The protein-sparing effect of carbohydrate. 2. The role of insulin.

1. In five experiments with growing female pigs of 38-63 kg, insulin (2 mU/kg) per min) and glucose (9-17 mg/kg per min) were infused continuously for 3-7 d. In three further experiments, glucose (9 mg/kg per min) was infused alone for 5 d.

Metabolism of intravenous adenine in the pig.

1. Adenine administered either parenterally or orally is less toxic to the pig than to other species; doses of 100 mg/kg are rapidly catabolised and excreted largely as soluble purine end-products in the urine. 2.

Thiopurinol: dose-related effect on urinary oxypurine excretion.

1. The important fact which emerges from these studies both without and with dietary purine supplementation is that thiopurinol dose possess apparent in vivo xanthine oxidase inhibitory activity but the dose must be increased well above therapeutic levels for this effect to manifest. 2.

Uric acid excretion by the pig kidney.

The handling of uric acid by the pig kidney has been investigated during continuous urate infusion in unrestrained, unanesthetized animals. Urate-to-inulin clearance rates in excess of 1 were found under all experimental conditions, demonstrating only net secretion by the pig kidney. The demonstration of a secretory maximum was precluded owing to a progressive reduction in the GFR associated with high rates of urate infusion.

Experimental crystal nephropathy (one year study in the pig).

An acute crystal nephropathy was produced in pigs by feeding a mixture of guanine and allopurinol. The pathogenesis of the lesion produced was studied by serial histology and renal function tests over 12 months. Tubular blockage by the crystals produced erosion of the basement membrane and an accompanying interstitial nephritis.

Renal biopsy in the pig.

In the pig, needle renal biopsy proved a safe and simple procedure which caused little discomfort to the animal. It proved a valuable method for following serial changes in renal histology and can therefore be applied to the study of both spontaneous and experimental renal diseases in pigs.