Table 2.

Concentrations of rapamycin and metformin in circulation. Whole blood was collected ~ 3 h after food had been removed from the cages of guinea pigs and was analyzed for rapamycin and metformin concentration by tandem HPLC/MS. N = 4 per group. The blood concentration of rapamycin and metformin in the control group were below the detectable limits of the HPLC/MS/MS. Data are presented as mean ± SD

	Experimental Diet
	Control	Rapamycin	Rapamycin+Metformin
Circulating rapamycin (ng/mL)	< 0.5 ± 0	72 ± 8	78 ± 10
Circulating metformin (ng/mL)	< 4 ± 0	-	282 ± 54