Liver and kidney cortex gluconeogenesis from l-alanine in fed and starved rats

Abstract 1. 1. Circulating [ 14 C]glucose 2, 5 and 10 min after intravenous injection of [U- 14 C]- l -alanine was greater in 24 hr starved than in fed rats. 2. 2. In vitro uptake of [ 14 C]alanine by liver and kidney cortex slices from 24 hr starved and fed rats rose in parallel with increased medium substrate concentration. 3. 3. Formation of [ 14 C]glucose from 1 mM [ 14 C]alanine was similar in liver and kidney cortex slices and increased in tissues from 24 hr starved compared with fed rats. With 5 mM [ 14 C]alanine more [ 14 C]glucose was produced by liver than by kidney cortex slices from 24 hr starved rats. Liver slices always produced more [ 14 C]lactate and less [ 14 C]-CO 2 from [ 14 C]alanine than kidney cortex slices. 4. 4. It is proposed that under physiological conditions, the kidneys cortex actively participates in glucose production from alanine.