The impaired purine metabolism in ischemic kidney injury was also reported before that the kidney injury could be ameliorated by the supplements of adenosine, inosine and guanosine. However, no obvious impairment was detected for the pyrimidine metabolism such as cytidine, thymidine, and uridine. In addition, the significant accumulation of urate in the kidney may result from the less excretion after kidney injury, which could further induce hyperuricemia, though the increase of urate in plasma was detected at 48 hour and 1 week reperfusion time without statistically significance. As a component of its normal function, particularly for the medulla, the kidney is exposed to osmotic extremes and is known to make use of small molecule organic osmolytes in maintaining osmotic balance. Among key players in osmotic regulation are the Azimilide glucose-derived polyols sorbitol and inositol, betaine, taurine, and choline-derived glycerophosphocholine. The polyol pathway has been implicated as a component of renal injury induced by ischemic hind limb though the mechanism is unknown. In our study, the small molecule osmolytes sorbitol, myoinositol, betaine, and GPC showed anticipated relative accumulation in kidney medulla Dantrolene sodium hemiheptahydrate compared to kidney cortex in the sham conditions and strong immediate and sustained decreased levels in kidney medulla following ischemia/reperfusion. In plasma, myoinositol and GPC also showed decreased levels at early time points but their levels returned to near-sham levels by one week. However, taurine did not show obvious decreases in all these three matrices. Overall, the time course of change in metabolite levels for multiple osmolytes indicates that the perturbation in osmotic regulation may be a key component to the ischemia/reperfusion metabolomic signature in both kidney medulla and plasma, which is sustained till one week reperfusion time in kidney. It is not surprising that the decline of renal function may affect the osmotic regulation. However, it would be interesting to speculate that the decrease in these osmolytes may also contribute to tissue damage. However, there are multiple additional polyols with other patterns of change.