Conversion of orally administered 2-n.pentylaminoacetamide into glycinamide and glycine in the rat brain

Male Sprague Dawley albino rats were treated orally with 2-n.pentylaminoacetamide (10 to 100 mg/kg b.wt). This oral administration provoked a dose-related and time-dependent accumulation of glycinamide in forebrain, cerebellum, and medulla, and to increased levels of glycine in the three brain areas, and of serine in medulla. In kidney, liver and plasma, the accumulation of glycinamide was lower and there was no increase in glycine and serine levels. With a dose of 100 mg/kg b.wt, 28% of the drug were eliminated unchanged and 16% as glycinamide, in urines collected for 24 h. In all tissues examined, 2-n.pentylaminoacetamide and glycinamide levels peaked at 1 h and were nil again after 24 h, the ratio of 2-n.pentylaminoacetamide over glycinamide decreasing more rapidly in brain than in kidney and liver. Contrasting with the effects of 2-n.pentylaminoacetamide, the oral administration of glycinamide (66 mg/b.wt) led, 2 hours later, to similar low rises of glycinamide in plasma and brain. In another control experiment, the intraperitoneal injection of a large dose of glycine (450 mg/kg b.wt) provoked, 30 min later, modest rises of glycine levels in the central nervous system that merely reflected a contamination by plasma glycine.