Renal mechanisms of calcium and phosphates homeostasis in rats at the early stages of alloxan-induced experimental diabetes mellitus under conditions of pharmacological blockade of the renin–angiotensin–aldosterone system

Olha Olenovych; Anatoliy Gozhenko; Yelyzaveta Tkach; Olena Glubochenko

Olha Olenovych Department of Clinical Immunology, Allergology and Endocrinology, Bukovinian State Medical University, Chernivtsi, Ukraine
Anatoliy Gozhenko SE Ukrainian Scientific Research Institute of Transport Medicine of Ministry of Health of Ukraine, Odesa, Ukraine
Yelyzaveta Tkach Department of Internal Medicine, Clinical Pharmacology and Occupational Deseases, Bukovinian State Medical University, Chernivtsi, Ukraine
Olena Glubochenko Department of Propaedeutics of Internal Diseases, Bukovinian State Medical University, Chernivtsi, Ukraine

Keywords: alloxan, experimental diabetes mellitus, calcium, phosphates, renin–angiotensin–aldosterone system

Abstract

The objectives of the research were to study the peculiarities of the intrarenal mechanisms of calcium and phosphates homeostasis regulation against the background of pharmacological blockade of the intrarenal renin-angiotensin system at the early stages of alloxan-induced experimental diabetes mellitus. The experiments were carried out on 26 white non-linear mature male rats – 16 animals with 11-day long alloxan-induced experimental diabetes mellitus and 10 intact animals of the control. Pharmacological blockade of renin–angiotensin–aldosterone system was induced by captopril administration to 8 diabetic rats. The results of the present experimental study evidence that in addition to its well-known effects on intrarenal hemodynamics, the renin–angiotensin–aldosterone system plays an important role in the modulation of sodium-dependent tubular transport processes of calcium and phosphates. The increase of sodium-dependent excretion of calcium and phosphates in rats with 11-day alloxan-induced experimental diabetes mellitus is predominantly of a hyperdynamic–hyperperfusion nature. Limitation of sodium ions reabsorption is accompanied by a decrease in the intensity of sodium-dependent calcium and phosphates reabsorption processes. Despite the inability of pharmacological RAAS blockade to eliminate the hemodynamic-hyperperfusion consequences of hyperfiltration, compensatory-functional renal mechanisms of calcium and phosphates metabolism remain preserved at this stage of experimental alloxan-induced diabetes mellitus, ensuring effective maintenance of their homeostasis.