[The age-related characteristics of changes in osmotic and ionic homeostasis in spontaneously hypertensive rats]

The 3-month old SHR differ from the WKY rats in that the former have an increased osmolality, concentration of albumins, activity (but not the concentration) of sodium and a reduced activity of potassium. The shifts in the albumins concentration occur, mainly, on account of the amino acid phenylalanine. The gradient increase of the sodium and potassium concentration between the plasma and muscular tissue in followed by a slight hyperpolarisation of the muscle fibers, a drop in the lability and a increase in pO2. The above shifts of homeostatic parameters were not revealed in the SHR and WKY rats of 1.5 and 6.0 months of age.