Effects of Age, Renal Failure and Co-administration on the Disposition of ¹⁴C-L-DOPS in Rats

Abstract

1. After a single oral administration of ¹⁴C-L-DOPS (10 mg/kg), substantially no differences in serum ¹⁴C levels, ¹⁴C excretion and urinary excretion rates of motabolites were found between aged (53 weeks old) and young adult (7 weeks old) rats.
2. Acute renal failure in rats was induced by the subcutaneous administration of mercuric chloride (2 mg/kg). After a single oral administration of ¹⁴C-L-DOPS (10 mg/kg) to rats with renal failure, serum ¹⁴C concentrations rose untill 8 hours and the area under the serum ¹⁴C concentration vs time curve was 10 times higher than that of normal rats. Radioactivity was excreted into urine, feces and expired air more slowly but in the similar pattern as compared with normal rats.
3. Serum ¹⁴C levels, ¹⁴C tissue distribution and ¹⁴C excretion in rats were not affected by co-administration of ¹⁴C-L-DOPS (10 mg/kg) with L-DOPA (10 mg/ kg) or with both of L-DOPA (10 mg/kg) and benserazide (2.5 mg/kg). Co-administration of ¹⁴C-L-DOPS with L-DOPA and benserazide gave higher concentrations of L-DOPS and lower concentrations of both NE and HMPG, when compared with co-administration with only L-DOPA.