In experiments on three age groups of laboratory rats (Wistar strain) evidence was provided that phosphocreatine (Neoton, Alfa-Sch. Wasermann) administered by the intraperitoneal route, 1 g/kg body weight, has an obvious protective effect on the shift of important values of the milieu interior altered by standard hypoxia (hyperbaric hypoxia corresponding to 9000 m and lasting for 20 min, pO2 = 6.4 kPa at a temperature of 20 °C). This protective action was most marked in full grown rats (age 90 days) where glucose utilization as well as the pathway of its processing into lactate and the calcium blood level were affected. All investigated parameters (blood sugar, calcium blood level, and the lactate and pyruvate) levels displayed smaller changes as compared with those caused by hypoxia alone. The younger rats, the smaller protective action of phosphocreatine. The lactate level was most markedly altered in 21-day old rats, although in both groups of young rats (15-day-old and 21-day-old) there was no marked change in the glucose utilization even after hypoxia. The most sensitive of the investigated parameters was lactic acid (lactate). It may thus be stated that phosphocreatine is a substance which by its wide biological activity can have a positive impact on the general metabolic situation of the organism exposed to hypoxia and increase thus hope of survival or a more favourable course of restorative processes.

        Key words: phosphocreatine, ontogenesis, hypoxia, protective action, blood serum