MORPHOLOGIC AND BIOCHEMICAL CHANGES IN THE GUT AFTER CHRONIC TREATMENT WITH l-DOPA

¹ Departments of Pharmacology and Toxicology and of Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, New York

Rats treated daily with l-dopa, 100 mg/kg, weighed significantly less (341 ± 13.2 g) than their matched controls (395 ± 8.8 g) at the end of a two-month treatment period, although there was no observed difference between the two groups in food and water intake. There was impaired absorption of d-¹⁴C-xylose in the l-dopa-treated rats, as shown by significantly lower radioactivity in the plasma and urine (P < .01) and significantly higher radioactivity in gut washings and stools (P < .001) in treated then in control rats. Electron microscopy and biochemical assay revealed significant increases in lysosomes and levels of lysosomal enzyme activity (glucosidases, acid phosphatases, -xyiosidase and cathepsinand trypsin-hike activity) in gut tissue of l-dopa-treated rats. These increases were not observed in the heart or brain tissue from the same rats. In the stomach, the most prominent cell types exhibiting alterations were the parietal and argyrophil cells. The chief, argentaffin and mucous cells did not show marked changes. These findings may have imphications in regard to the clinical use of l-dopa in Parkinson's disease.