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Purification of pronase by ion-exchange chromatography gave four proteolytically active fractions. Fraction A(2) contained an endopeptidase that attacks poly l-valine. Fraction B contained an endopeptidase, an aminopeptidase and carboxypeptidases. The activities against hippuryl-l-arginine and hippuryl-l-phenylalanine could be inhibited to a considerable extent by di-isopropyl phosphorofluoridate and by EDTA. Fraction C contained an endopeptidase resembling bovine trypsin. The pure enzyme was completely inactivated by di-isopropyl phosphorofluoridate and pancreatic trypsin inhibitor and to about 90% by other naturally occurring trypsin inhibitors. Fraction D contained an apparently homogeneous endopeptidase, inhibited by diisopropyl phosphorofluoridate, that adsorbed to and hydrolysed elastin. The activity of all these fractions was tested qualitatively against a wide range of small peptides and synthetic substrates.

1. (+/-)-2-Amino-1-phenyl[1-(14)C]propan-1-ol ([(14)C]norephedrine) was administered orally to man, rat and rabbit and the metabolites excreted in the urine were identified and measured. Pronounced species differences in the metabolism of the drug were found. 2. Three male human subjects, receiving 25mg each of [(14)C]norephedrine hydrochloride, excreted over 90% of the (14)C in the first day. The main metabolite was the unchanged drug (86% of the dose) and minor metabolites were hippuric acid and 4-hydroxynorephedrine. 3. In rats given 12mg of the drug/kg almost 80% of the (14)C administered was excreted in the first day. The major metabolites in the urine were the unchanged drug (48% of the dose), 4-hydroxynorephedrine (28%) and trace amounts of side-chain degradation products. 4. Rabbits given 12mg of the drug/kg excreted 85-95% of the dose of (14)C in the urine in the first 24h after dosing. The major metabolites in the urine were conjugates of 1,2-dihydroxy-1-phenylpropane (31% of the dose) and of 1-hydroxy-1-phenylpropan-2-one (27%) and hippuric acid (20%). The unchanged drug was excreted in relatively small amounts (8%).

The dominant aerobic microorganism in cattle feedlot waste (FLW) is a corynebacterium. It is ubiquitous to FLW except on sites where antibiotics are a constant part of the animals' diet. The organism requires DL-aspartic acid as its nitrogen source for growth, and individual strains also require or are stimulated by L-tyrosine; acetate serves as the carbon source. Amylolytic activity is weak; protease, lipase, and cellulase activities are nil. Despite the abundance of the organism, it probably does not decompose the waste appreciably.

1. In the anaesthetized dog bombesin had a potent antidiuretic effect, and sometimes arrested urine flow completely. Threshold doses, by i.v. infusion, were of the order of 0.5-1 (ng/kg)/minute. Antidiuresis was the result of a reduction in glomerular filtration rate provoked by a fall in intraglomerular hydrostatic pressure. This, in its turn, was due to afferent vasoconstriction.2. The spasmogenic effect of bombesin on the smooth muscle of the afferent arterioles was directly demonstrated by the radioactive microspheres technique and indirectly by the (85)Kr washout method and by [(3)H]-p-aminohippurate clearance. The vascular compartment most sensitive to bombesin was that of the outer cortical zone, especially in its external half.3. Filtration fraction decreased under the influence of bombesin, indicating that the effect of the polypeptide on postglomerular arterioles was, if present, only of minor importance.4. At high infusion rates (above 6 (ng/kg)/min), bombesin produced a decrease in [(3)H]-p-aminohippurate extraction. The effect of the polypeptide on fractional distal delivery of sodium varied with the dose: at moderate infusion rates it decreased, at high infusion rates it increased. The total glucose appearing in urine following a glucose load was sharply reduced by bombesin. However, the glomerular filtration rate/maximum tubular glucose transport ratio did not show any appreciable change.5. Afferent vasoconstriction produced by bombesin was accompanied by an intense activation of the renin-angiotensin system, as shown by a conspicuous increase in renin secretion, followed by increases in renin activity and angiotensin II concentration in arterial blood. When bombesin was infused into one renal artery only the infused kidney showed afferent vasoconstriction and increased renin secretion. The time-course of renin secretion produced by bombesin depended upon the rate of infusion of the polypeptide. At low rates an increased renin secretion was observed throughout the infusion period, at high rates two peaks of renin secretion could be seen, one at the beginning of the infusion, the other soon after the infusion had finished.6. The mechanism of action of bombesin is discussed and the interest of the polypeptide as a possible hormonal regulator of the circulation and function of the kidney is pointed out.

Endogenous creatinine, inulin, para-amino-hippurate and phenolsulphothalein clearances for healthy cats are presented. The values for inulin and para-aminohippurate clearances (ml/kg/min) are similar to those for the dog. Creatinine clearance was less than inulin clearance values. Pnenolsulphothalein clearance may be a better index of glomerular rather than tubular function in the cat.