Nitrogenous End Products Research Articles

Nitrogenous End Products of a Cockroach

Nitrogenous End Products of a Cockroach

Estimation of Nitrogenous Compounds in the Feces of Boll Weevils, Anthonomus grandis, Fed Different Diets

The effects on the nitrogenous end products of the metabolism of the boll weevil, Anthonomus grandis Boheman, fed on artificial diet, cotton squares, or bolls were determined. Fecal analyses for amino nitrogen, ammonia, creatine, creatinine, guanine, urea, and uric acid showed that presence of these materials varied with the type of diet fed the insects. The purine guanine was found in relatively large quantities in the feces of weevils fed all 3 diets. A metabolic block in its deamination was hypothesized.

Protein Metabolism in Chicks Fed Raw Soybean Meal

Abstract Evans et al. (1947) and Bouthilet et al. (1950) reported the digestibility of the protein of raw soybeans in chicks to be only about 80% of that of heat treated soybean meal. Renner and Hill (1960) showed significantly lower metabolizable energy values for raw soybean flakes and further reported that raw soybean meal interfered with fat absorbability in the chick. While metabolizable energy measurement provides an excellent means for determining the over-all utilization of the diet, it does not identify the nature or source of the products of excretion. In the present study the nitrogenous end products of urinary origin were estimated in order to determine if protein metabolism is altered in chicks fed raw soybean meal. Male New Hampshire × Delaware chicks used in the experiment were maintained in battery brooders with raised wire screen floors, kept in a temperature controlled and ventilated laboratory. Eight chicks were randomly assigned…

Guanine Excretion by the Two-Spotted Spider Mite (Tetranychus telarius (L.))1

Two purines have been shown to be nitrogenous end products in arthropods, namely uric acid in insects and guanine in spiders (Prosser 1950). Blauvelt (1945) found spherical concretions in the hindgut of the two-spotted spider mite which he classed as urates. As no malpighian tubes were present, the glandular cells in the anterior lateral walls of the hindgut (plate 2, Blauvelt 1945) were described as a specialized nephritic organ for the elimination of urates. Gasser (1951), however, on the basis of solubility tests, described not only the concretions in the hindgut but also part of the black fecal pellets as containing guanine. These spherical concretions accumulate in the hindgut and are passed with the fecal pellets.

Studies of fluid, electrolyte, and nitrogen balance in acute renal insufficiency.

ACUTE renal insufficiency, including the syndrome of lower nephron nephrosis, is characterized not only by retention of nitrogenous end-products but also by profound disturbance in fluid and electrolyte metabolism. Thorough understanding of the underlying pathophysiology is essential for the correct management of these patients. Bywaters1renewed interest in the syndrome of acute renal insufficiency with his description of azotemia following crushing injuries. The pathologic changes, the pathogenesis, and the clinical picture have been summarized recently by Burch and Ray,2Muirhead,3Strauss,4and Lucke.5 Since the maintenance of fluid and electrolyte equilibrium during the critical oliguric and early diuretic phase of lower nephron syndrome appears distinctly to influence the fatality rate, an effort has been made to study the nature of disturbances in these equilibria. Complete metabolic studies of sodium, potassium, chloride, nitrogen, and water balance were made in 5 cases of severe acute renal insufficiency for periods of 6 to 23

Guanine in the Excreta of Arachnids

SINCE the work of Gorup-Besanez and Will in 18491, it has been classical to regard guanine as taking the place of uric acid as the main nitrogenous end-product of arachnid metabolism. This view is accepted in all the monographs on comparative biochemistry, such as that of von Furth2, but it appears to rest wholly on colour tests of uncertain value and deductions from crystal form.

The effect of fasting and of vitamin B deprivation on the chemical composition of rats'blood

The recent publication of data on the blood of pigeons in polyneuritis and stavation suggested the desirability of publishing the data obtained on rats under similar conditions. The preliminary report on the influence of fasting and of vitamin B starvation has been amplified and data have also been obtained on fasting rats to whom water (10 to 21 c.c. daily) was administered by stomach tube during the last days of the fast. Total solids were determined by an adaptation of Peters'method and the other constituents by the methods of Folin and Wu. From the summary given in the table it is apparent that the non-protein nitrogen of the blood of fasting rats is 30-40 per cent higher than that of normal animals, the increase being practically all in the urea fraction. Total dry matter, creatinine and creatine are slightly increased. Fasting rats that are given water per os during the last few days of their fast show normal values for non-protein nitrogen and solids. The blood of rats deprived of vitamin B also gives figures that are normal except that creatinine is at the fasting level and creatine slightly higher than the fasting figure; these differences have little if any significance in the present state of uncertainty with regard to blood creatine and creatinine determinations. Deprivation of vitamin B in contrast to fasting is not accompanied by an accumulation of nitrogenous end-products in the blood; whatever the ultimate cause of this increase may be in fasting, it is prevented by administration of water.

THE VALUE OF THE ESTIMATION OF UREA, NONPROTEIN NITROGEN AND CREATININ

Our knowledge of blood chemistry, so far as it concerns renal disease, is of comparatively recent origin. The development of simplified methods of estimating the amount of the various substances in health and disease has rapidly led to the accumulation of enormous data concerning their variations. Estimations of total nitrogen by the Kjeldahl method have been made for a number of years, but this method is too intricate for general clinical use and can be carried out only by trained chemists in well-equipped laboratories. From the determinations made by this method, however, it was well known that in advanced renal disease the total nitrogen in the blood was greatly increased, and later observations have shown that this increase is due in great measure to the retention of nitrogenous end-products, normally excreted by the healthy kidney. As urea is the most prominent of these substances, blood urea determinations were at first,

PROTEOSE INTOXICATIONS AND INJURY OF BODY PROTEIN

The acute intoxication following an injection of a toxic proteose is usually associated with a large increase (40 per cent or more) in the non-protein nitrogen of the blood. This increase is found chiefly in the blood urea nitrogen, but the amino and peptide nitrogens also may show small increases. The changes observed in the blood non-protein nitrogen are identical with those which follow the feeding of large amounts of meat (8). These facts indicate that the proteose intoxication causes an abnormally rapid autodigestion of tissue proteins, but that the nitrogenous end-products are, in chief part at least, the same that result from normal catabolism of food proteins. There is no evidence that the autolytic products play any part in causing the intoxication. The possibility of such a part and a resultant vicious circle is not excluded, but from the available facts the autolysis appears more as a result rather than cause of the intoxication. It appears possible that in disease or intoxication tissue catabolism may be enormously accelerated and yet yield the end-products of normal protein metabolism.