HISTOPHYSIOLOGY OF VASCULAR GLOMERULES AND JUXTAGLOMERULAR APPARATUS OF KIDNEYS AFTER PROTEIN LOAD AND STARVATION

Abstract

THE AIM of the investigation was to study in dynamics the state of the capillaries of glomerules of the superficial and juxtaglomerular nephrons and the ultrastructure of juxtaglomerular apparatus (JGA) of the kidneys after protein load and starvation. MATERIAL AND METHODS. The experiments were carried out in 30 white outbred male rats with body mass 120-140 g. Morphological investigation of the degree of opening the glomerular capillaries of the superficial and juxtaglomerular nephrons and the ultrastructure of JGA was made in a control group consisting of animals 1 day after intraperitoneal administration of 5.0 cm³ of 6% solution of albumin, after 3 days (the 3rd group) and after 1 and 6 days of starvation (the 2nd group). RESULTS. Dilatation of the afferent and constriction of efferent arteriols, increased portion of glomerules with greater degree of opening the capillaries (DOC) and activation of JGA cells were observed in a day after protein load. Three days later, with normalization of JGA structure, DOC of both superficial and juxtaglomerular nephrons was greater than in control animals. After 3 days of starvation DOC in both types of nephrons was increased and there was no activation of JGA. In 6 days DOC was increased and was synchronized in juxtaglomerular nephrons only; JGA was in hypofunctional state. CONCLUSION. The structural-functional features of the cells of JGA and glomerular capillaries of superficial and juxtaglomerular nephrons are naturally determined and directed to an increase of the functional reserve, maintenance of homeostasis, correspond to multi-level principle of self-regulation and integration, systemic principle of complicating the structures and functions of the kidney.