Streptozotocin (STZ), a compound composed of a mixture of alpha and beta anomers, is used experimentally for the chemical induction of diabetes mellitus in numerous animal species. It is routinely recommended that STZ be administered rapidly following dissolution because of its alleged instability in solution. In the present study, we examined the effect of varying the length of time from dissolution to administration on the ability of STZ to induce diabetes mellitus in male Syrian golden hamsters and examined STZ stability and state of equilibrium by high-pressure liquid chromatography. Effective diabetes induction was determined by monitoring plasma glucose concentrations 2 and 9 days after STZ treatment. Diabetes was successfully induced with solutions of STZ (50 mg/kg body weight given intraperitoneally on three consecutive days) used either immediately (24 degrees C), 2 hours (24 degrees C), or 5 to 7 days (6 degrees C) after dissolution in 0.1 M acetate buffer at pH 4.4 (storage temperature indicated in parentheses). Mean plasma glucose concentration was significantly higher in all STZ treatment groups at both time points when compared with acetate buffer-treated controls. There was no significant difference in plasma glucose concentration between STZ treatment groups. High-pressure liquid chromatography analysis demonstrated that the alpha- to beta-anomeric ratio of STZ had reached equilibrium in 84 minutes at 24 degrees C and by 26 hours at 6 degrees C following dissolution. Recovery of STZ was greater in solutions stored at 6 degrees C than at room temperature (24 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)