[Show abstract][Hide abstract] ABSTRACT: We have investigated the metabolic effects of IBMX (3-isobutyl-1-methyl xanthine, a non-selective PDE inhibitor), amrinone, MC7 (6-(4-(tetrahydro-2H-pyran-4-yl)-4-oxobutoxy)-4-methylquinolin-2(1H)-one) and MC9 (6-(4-(1-ethylpiperidin-4-yl)-4-oxobutoxy)-4-methylquinolin-2(1H)-one) (selective PDE3 inhibitors) on immature balb/c mice . Controls included groups of mice that received no intervention (control 1) and a group injected with 1mg/kg of drug carrier (control 2). The four experimental groups were weighed and injected separately with IBMX, amrinone, MC7 and MC9 (1mg/kg) daily for seven days after which they were killed and 59 blood and tissue samples were collected. The administration of drug carrier into the male mice, decreased the growth pattern during the second (P<0.05) and third (P<0.001) day. After the injection of drug carrier, there wasn’t any significant difference between the growth pattern, and the concentrations of biochemical factors in the male, comparing with female mice. Therefore, a group of mice, including both male and female, was used. MC7 decreased the growth pattern on the day two (P<0.01). IBMX increased glucose (P<0.05), triglyceride (P<0.05) and glycogen (P<0.01) concentrations, whereas amrinone decreased the glucose (P<0.05) comparing with control 2. The ability of stress tolerating in immature female mice was more than that in the male mice. In spite of the similar inhibition influence, the experimental drugs used in this study, had different metabolic effects.