INS and diabetes mellitus: Goyal et al. [41] explain that the action of STZ in terms of inducing diabetes has three phases: the first phase occurs two hours after its administration, during which hepatic glycogen is broken down to produce transient hyperglycemia and hypoinsulinemia; the second phase begins 10 h later, with hypoglycemia mediated by massive insulin release from ruptured beta cells; and the third begins 24 h later, when stable hyperglycemia and hypoinsulinemia are established.