Effect of Erythroxylum coca, cocaine and ecgonine methyl ester as dietary supplements on energy metabolism in the rat

The effects of dietary supplements of cocaine, ecgonine methyl ester, a coca leaf extract and powdered coca leaves on body weight and overall body metabolism were studied in the rat. Respiratory quotient was measured to assess the relative utilization of fats, carbohydrates and protein. The effect of cocaine and ecgonine methyl ester on protein metabolism was also assessed in terms of changes in the relative state of nitrogen balance. Rats maintained on a low protein/high carbohydrate diet containing cocaine (1 mg/g) exhibited normal body weight gain on normal food intake. Rats on the same diet with 2 mg/g cocaine as the hydrochloride or as coca dextrin lost weight, which was apparently related to diminished food intake. In contrast, rats received the same high level of cocaine as coca leaf powder in the same diet had minimal weight gain in spite of a high food intake. In contrast, rats receiving the same high level of cocaine as ly, rats receiving the same high level of cocaine (2 mg/g) in a high protein diet had normal food intake and body weight gain. An adequate protein diet appears to compensate for whatever inhibiting effect is imposed on the body by the high levels of cocaine. Ecgonine methyl ester appears to have no significant effect on food intake or body weight. Rats fed the low protein/high carbohydrate diet containing either the low (1 mg/g) or the high (2 mg/g) cocaine level exhibited significantly depressed respiratory quotients (near 0.75) suggesting increased fat utilization. The magnitude of the reduction appeared to be dose-related. Yet, the respiratory quotient of the rats receiving the high level of cocaine in a high protein diet remained at normal control values. Also, in a separate nitrogen balance-type of experiment, rats receiving the low level of cocaine (1 mg g low protein/high carbohydrate diet) exhibited a normal ability to accumulate body nitrogen, presumably protein. These results support the idea that under conditions of protein deprivation cocaine helps spare amino acids through the preferential utilization of fat. Coca leaf in the low protein/ high carbohydrate diet equivalent to 2 mg g cocaine had a small but significant positive effect on respiratory quotient possibly due to the availability of utilizable nitrogenous components in the coca leaf. The respiratory quotient effects were less obvious with an extract of coca leaf incorporated in the diet as coca-dextrin, but showed the same trend. Ecgonine methyl ester at a le