By the use of the Bowie staining technique, juxtaglomerular cells or their homologues were identified in almost every member of Osteichthyes studied. Despite the fact that juxtaglomerular cells in the mammal, at least, belong to the sodium-retaining rennin–angiotensin–aldosterone system they occurred with frequency in salt-water as well as freshwater fish. Early evidence for the presence of renin in the kidney of certain freshwater fish was strengthened by the identification of granulated afferent arteriolar cells in the kidneys of these species. In an attempt to determine which structural components are necessary for the development of juxtaglomerular cells, their anatomical relationships in the fish were compared with the ones existing in higher forms.
Experiments were carried out to determine whether alloxan diabetes in rats altered:(1) the level of plasma seromucoid (a small carbohydrate-rich fraction), (2) the perchloric acid (PCA)-insoluble protein, making up the remainder of the plasma protein, and (3) the ability of the animal to incorporate [14C]glucosamine and [14C]leucine into these plasma fractions.Diabetes was produced in 20 male Wistar rats (250-275 g) by the following procedure. Rats, fasted for 16 h, were lightly anaesthetized with ether and injected i.v. with alloxan (70 mg/kg) in 0\m=.\9 % NaCl solution acidified to pH 3\m=.\5. They were then given protamine zinc insulin s.c. at a daily dose of 2 u. for 7 days, 1 u. for 5 days and 0\m=.\5 u. for 5 days. Experiments were carried out 3 days after the last dose of insulin. In the 24 h preceding the experiments, urinary output of glucose per rat was 667 \ m=+-\ 46 (S.E.M.) mg. Control Wistar rats were matched by weight.Ten diabetic and ten control rats were injected i.v. with 5 /tCi [l-14C]glucosamine/ 220 g body weight. The remaining ten diabetic and ten control rats were similarly injected with 10/iCi [14C]leucine/220 g body weight. Blood (1 ml) was withdrawn from the jugular vein every hour for 4 h after the injection. Seromucoid and PCAinsoluble protein were separated (Winzler, Devor, Mehl & Smyth, 1948) and the pro¬ tein of each fraction assayed (Lowry, Rosebrough, Farr & Randall, 1951). Radio¬ activity of each of these fractions and of the protein-free supernatant was measured on a Nuclear Chicago gas-flow low-background counter. Specific activity was calculated on each sample of protein. The values obtained at 4 h were analysed statistically because they had reached a plateau by this time.Total plasma protein levels in the diabetic rats were not changed significantly but a significant depression (P < 0-001) occurred in the PCA-insoluble fraction (19494 + 414 v. 22 843 + 363 µg|mí blood in the controls). The seromucoid levels in the dia¬ betic rats, normally 1/43 of the total plasma protein of the normal rat, remained un¬ changed (564 + 20 v. 529 + 20 /ig/ml blood in the control animals). One hour after the injection of isotope, less than 0-2 % of the injected radioactivity was left in the cir¬ culation in any experiment, indicating rapid incorporation and/or excretion of both glucosamine and leucine.Four hours after the injection of [l-14C]glucosamine the specific activity of the seromucoid in the diabetic rats exceeded that of the control group (P < 0-025). The
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.