[Characteristics of sodium metabolism in rats with experimental hypertension caused by chronic alimentary imbalance]. / Osobennosti obmena natriia u krys s éksperimental'noi gipertenziei, obuslovlennoi khronicheskim alimentarnym disbalansom.

Beginning from 1.5 month of life Wistar rats were kept under conditions of chronic 1 and 2% salt loading combined with a low-protein diet (6-8% of protein VS, as compared with 23-24% in the normal diet). At the age of 14-16 months when a stable hypertension developed due to the above alimentary imbalance, their sodium metabolism was studied using whole-body radiometry with 22Na. A three-chamber model of 22Na metabolism was developed for the analysis of 22Na excretion from the body. This helped in establishing the heterogeneity of sodium metabolism in experimental animals. Besides that, it has been shown that not only sodium retention in the body, but also its redistribution between intra- and extravascular sections play an important role in the development of hypertension. Protein deficiency in the diet aggravates sodium metabolism disorders in experimental animals.

[Sodium metabolism in Wistar rats exposed to chronic isotonic salt load after preliminary protein deficiency in the diet according to radiometry of the whole body with 22-Na]. / Obmen natriia u krys vistar v usloviiakh khronicheskoi izotonicheskoi solevoi nagruzki posle predvaritel'nogo defitsita belka v diete po dannym radiometrii vsego tela s 22Na.

The long-term preliminary protein deficiency in the diet gives rise to irreversible changes in sodium metabolism in experimental animals exposed subsequently to chronic salt load combined with full-value feeding. Apparently such changes do not go, however, beyond the compensatory potentialities of the body exposed to isotonic salt load, since the systolic arterial pressure does not undergo any material changes throughout the whole experiment.

[Characteristics of sodium metabolism in Wistar rats in relation to the uptake of sodium chloride studied by whole body Na-22 radiometry]. / Osobennosti obmena natriia u krys linii Wistar v zavisimosti ot urovnia potrebleniia povarennoi soli po dannym radiometrii vsego tela s radionuklidom 22Na.

The rate of sodium elimination was shown to be inadequate to sodium uptake in rats exposed to prolonged salt loading, the higher the load, the greater the inadequacy. Sodium distribution between vascular and extravascular spaces of the body was also disproportionate in conditions of both excessive and low sodium uptake.

[Modeling of experimental hypertension by chronic salt loading combined with a low-protein diet in Wistar rats]. / Modelirovanie eksperimental'noi gipertonii s pomoshch'iu khronicheskoi solevoi nagruzki v sochetanii s nizkobelkovoi dietoi u krys Vistar.

Combination of chronic salt loading with protein-poor diet produces experimental hypertension with natrium consumption near to physiological. The present model is characterized, compared to the existing one, by stage development, moderate arterial blood pressure elevation and absence of "salt toxicosis" and may be thus considered more adequate for experimental investigation of primary arterial hypertension pathophysiology.

Sodium metabolism in Wistar rats during a chronic high-salt or a low-protein diet: 22Na determination by radiometry.

Whole body radiometry was employed to monitor 22Na radionuclide metabolism in Wistar rats of either sex, aged six months and 1.3 years, kept under normal conditions or on a low-protein diet or during chronic salt load over a period of one year. In all the groups studied, the differences in sodium metabolism according to sex and age were determined. Tissue sodium metabolism was statistically significantly slowed (p less than 0.001) in male and female rats on a high-salt diet compared with the control group. Renal sodium excretion was significantly increased in the high-salt diet group. In the low-protein diet group, tissue sodium metabolism was significantly faster than in control animals, and this both in female (p less than 0.01) and male rats (p less than 0.001). Renal sodium excretion was, however, significantly lower in male rats (p less than 0.001) than in control animals.