We measured the impact of one week of chronic constant hyperglycemia (CHG, n = 6) versus pulsatile hyperglycemia (PHG, n = 5) versus controls (n = 7) on the percentage of the fetal pancreas staining for insulin (β-cell area), mitotic and apoptotic indices and size of fetal β-cells, and fetal insulin secretion in sheep. The gene discussed is INS; the disease is Hyperglycemia.