| Abstract: | Fourteen-day-old and adult rabbits received procaine penicillin G (PEN), 450,000 U/kg s.c., every 12 hours for a total of four doses or phenobarbital-Na (PHB), 40 mg/kg i.p., once daily for 3 days, or 3-methylcholanthrene (3MC), to 20 mg/kg i.p., once daily for 3 days. Twenty-four hours after the final treatment the animals were killed and the kidneys were removed for analysis of enzymatic activities and p-aminohippuric acid (PAH) transport capability. PEN, PHB and 3MC had no effect on PAH transport in slices from adult rabbits but significantly increased PAH transport in slices from 14-day-old rabbits. Aryl hydrocarbon hydroxylase activity was enhanced in both adult and 2-week rabbit kidneys by 3MC while biphenyl-4-hydroxylase activity was enhanced in 2-week and adult rabbit kidneys by PHB. Epoxide hydratase was unaffected by all three treatments. 3MC increased gluthione-S-aryltransferase (ligandin) activity in 2-week but not adult kidneys. Induction of PAH transport in 14-day-old rabbits does not appear to be related to stimulation of microsomal enzymes or glutathione-S-aryltransferase activity in the kidney. Although they are not considered to be substrates for renal organic anion transport, PHB and 3MC resemble PEN in their ability to induce PAH transport in renal cortex of immature but not adult rabbits. |
