In 1916 Nicolae Paulescu , a Romanian professor of physiology at the University of Medicine and Pharmacy in Bucharest , developed an aqueous pancreatic extract which , when injected into a diabetic dog , had a normalizing effect on blood-sugar levels .
Nicolae Paulescu , a Romanian professor of physiology at the University of Medicine and Pharmacy in Bucharest , was the first to isolate insulin , in 1916 , which he called at that time , pancrein , by developing an aqueous pancreatic extract which , when injected into a diabetic dog , proved to have a normalizing effect on blood sugar levels .