EFFECTS OF PHENYLPROPANOLAMINE INFUSION AND WITHDRAWAL ON BODY-WEIGHTAND DIETARY-COMPOSITION IN MALE AND FEMALE RATS

Male and female rats with ad lib access to separate sources of carbohy drate, fat, and protein were implanted with minipumps providing one of three dosages (0.0, 40.0, or 80.0 mg/kg/day) of phenylpropanolamine ( PPA) for 2 weeks. Body weight, macronutrient intake, and water consump tion were measured daily before, during, and after PPA treatment. Phen ylpropanolamine lowered body weight and caloric intake in males and fe males, and water consumption in females, but did not alter dietary com position in either sex. After PPA termination, caloric intake returned to control levels in both males and females. However, body weight ret urned to contol levels in males only, while PPA-treated females contin ued to weigh less than controls. Phenylpropanolamine termination was a ssociated with significant increases in water consumption and the perc entage of total calories consumed from protein and reductions in the p ercentage of calories from carbohydrate in males. In contrast, water a nd macronutrient consumption was similar comparing PPA-treated females to controls after drug termination. These results suggest there are s ex differences in the effects of PPA termination on water and macronut rient consumption that result in differential weight gain in males and females.