The aims of this study were 1) to determine whether transfer of blood urea to the gastrointestinal tract (GIT) or the efficiency of capture of urea N within the GIT is more limiting for urea N salvage, and 2) to establish the relationship between plasma urea concentration and recycling of urea N to the GIT. We used an i.v. urea infusion model in sheep to elevate the urea entry rate and plasma c...

According to the usually accepted concept, the urea removed from the blood by the kidneys is excreted in two forms, chiefly as urea itself, but partly as ammonia. That the ammonia of the urine is formed in the kidneys was demonstrated by Nash and Benedict (1921), in work which has been confirmed by other authors (cf. Peters and Van Slyke, I, p. 373). Evidence from animal experiments in v4vo has...

In mammals, the majority of nitrogen from protein degradation is disposed of as urea. Several studies have partly characterized expression of urea transporters (UTs) in hepatocytes, where urea is produced. Nevertheless, the contribution of these proteins to hepatocyte urea permeability (P(urea)) and their role in liver physiology remains unknown. The purpose of this study was to biophysically e...

Gulf toadfish (Opsanus beta) use a unique pulsatile urea excretion mechanism that allows urea to be voided in large pulses via the periodic insertion or activation of a branchial urea transporter. The precise cellular and subcellular location of the facilitated diffusion mechanism(s) remains unclear. An in vitro basolateral membrane vesicle (BLMV) preparation was used to test the hypothesis tha...

SCHMIDT-NIELSEN, BODIL, AND CAROLYN RUTH SHRAUGER. Hundling of urea and related cumpuunds by the renal tubuks of the frog. Am. J. Physiol. PO&$: 483-488. 1963.-A high arginase activity is found in the kidney of the adult frog Ram catesbeiana which actively secretes urea. Urea accumulates in the kidney in concentrations around seven to eight times the blood concentration. To test whether the kid...

ROW-RAMEL, FRANCOISE, FRAN~OISE CHOMETY, AND G. PETERS. Urea concentrations in hh.darj?uid and in wnal tissue of nondiuretic rats. Am. J# Physiol. 2 15(Z) : 429-438. 1968.-Concentrations of urea and of inulin or polyfructosan were measured in proximal and distal tubular fluid of nondiuretic rats (P,,,, 5.5 =t 0.6 rn~) and rats infused with small doses of urea (P,,,, 11.8 + 1.1 mM>, Papillas and...

?Ur readers to form an opinion as o involved. They are not inconsiderab, Urea-Stibamine" has now a ;vell"^Stfnd the reputation in the treatment of kala-az , question of its supply and cost affects t ^ health Departments of four provinc caseApparently there were two issues i ^reahe first was as to the use of the na t^efamine the second the al|e|ad packed Ln,on Drug Co. was issuing the ciruj, f ^...

Sir,?In reply to Capt. T. D. W. Gillespie's inquiry in the Novtmber issue of the I. M. Q. as to the quantity of quinine urea hydrochloride to be injected hypodermically to produce local anaesthesia, I may say as follows: In the New York Medical Journal (1915, II, 708) Amster recommends quin-urea hydro as a local anaesthetic. He has performed 200 severe operations with a freshly prepared solutio...

Urea is the principal nitrogenous waste product of metabolism and is generated from protein breakdown. It is eliminated from the body almost exclusively by the kidneys in urine, and measurement of its concentration, first in urine and later in blood, has had clinical application in the assessment of kidney (renal) function for well over 150 years. This is the first of two articles that together...