[Quantitative relationship of renal blood flow with size and density of glomeruli in rat postnatal ontogenesis].

The aim of the study was to find the quantitative relationship of postnatal changes in the glomeruli anatomic structure with the blood flow in kidneys. Kidney development was studied in 4-, 12-, 30-, and 65-day-old Wistar rats. Diameters of glomerulus (Dgl, microm), afferent and efferent arterioles (Daf and Def), and the glomeruli density (Ngl, mm(-3)) were measured posthumously. Volumes of one ((see text of symbol))V gl, microm3) and all glomeruli (see text for symbol)(sigma(see text for symbol)Vgl, mm3/cm3) and the glomeruli arterioles lumen (Saf and Sef, microm2) were calculated. The renal specific blood flow (SBF per unit of kidney weight, KW) was measured by the laser-Doppler flowmeter (in perfusion units, p.u.) under sodium barbamyl narcosis. We have found that, during postnatal growth, glomeruli morphological parameters vary according to the equations: Dgl = 7.1 (see text for symbol) KW0.41, (see text for symbol)V gl = 187 (see text for symbol) KW1.23, Ngl = 5309 (see text for symbol) KW-0.63 (KW, mg and for one kidney), Saf = 1.1 (see text for symbol)V gl 0.35, and Sef = 6.3 (see text for symbol) V gl 0.14. The renal SBF in 4-, 12-, and 65-day-old rats increases according to SBF = 6.7 (see text for symbol) (sigma( see text for symbol)V gl)0.98. The renal SBF calculated per unit of glomeruli volume varies a little with age.

[Dynamics organ blood flow in rats in postnatal ontogenesis].

In the 4-, 13-, 30-, and 65- 90-day-old Wistar rats the voluminous blood flow rate was measured in liver, kidney, small intestine wall, and in the predominantly white gracilis muscle of femur. A LAKK-01 laser-Doppler flowmeter and its cutaneous (for kidney) and needle (for other organs) probes were used; they provided estimation of blood flow (per organ mass unit) to the tissue depth of about 1 mm. It has been found that the blood flow rates (per organ mass unit fall in liver, intestine, and even more in muscle, whereas increase in kidney, particularly for the first month of life. Calculations show that in adult rats as compared with the 4-day-old pups (with their mass exceeding 22 times) the blood flow to muscle, liver, intestine, and kidney should rise 14, 17, 18 and 43 times, respectively.

[The glomerular apparatus and renal blood flow in rats during postnatal ontogenesis].

In anesthetized Wistar rats of the age of 4, 12, 30 and 65 days, the renal blood flow (RBF) with laser-Doppler flowmetry, diameter, number and density of glomeruli, diameter of afferent and efferent arterioles were measured. We found that during rat development the RBF increased 2.8-fold, the diameter of glomeruli--3.6-fold, diameter of afferent arterioles--1.8-fold, and the efferent arterioles--rose 1.3-fold. The number of glomeruli increased 1.3-fold, but their density decreased 16-fold.