Some aspects of renal energy and lipid metabolism in newborn rats.

Some aspects of renal energy and lipid metabolism were studied in the postnatal period of rats. Oxygen consumption, RQ values, stimulation of oxygen consumption by exogenous substrates (8 mM glucose, 8 mM acetate, 1 mM palmitate), and conversion of acetate or palmitate to CO2 were measured in slices of cortex and inner medulla. The results obtained in 5-day-old rats are not essentially different from those observed in adults. On the other hand, the phenomenon of triacylglycerol storage in kidney cortex during starvation (well known in adult animals) is absent in the newborn rat. It can be demonstrated first in 30-day-old rats. At the same age renal arteriovenous concentration differences for total glycerol indicate a significant uptake during starvation and a release in the fed state.