INS and diabetes mellitus: We have also observed that the delivery of furin-cleavable human insulin (INS-FUR) directly to the livers of chemically-diabetic rats, spontaneously-diabetic NOD mice, and pancreatectomized pigs, resulted in the spontaneous expression of β-cell transcription factors, secretory granule biogenesis, reversal of diabetes, and normal glucose tolerance [16,17,18].