Factors influencing the plasma levels of amphetamine and its metabolites in catheterized rats

Rats fitted with chronically indwelling Silastic tubing catheters in the right jugular vein were given orally a low dose (0.067 mg/kg) of d-amphetamine sulfate (A) alone or in combination with other chemicals or environmental conditions. In general, A levels increased slowly over 1 hr, peaked and declined during the 4-hr test period. Levels of metabolites (M) were already appreciable at 15 min, slowly increased to 1 hr, and remained constant over the rest of the testing period. A variety of chemicals and environmental conditions that were meant to mimic some human situations (social interaction, food, stress, alcohol, bicarbonate and ammonium chloride) selectively affected the half-lives, the areas under the time-curve, and the levels of A and M at different times during the experiment. In two cases, individual differences in A and M blood levels were found in these rats, which belong to a genetically homogenous group.