To explore the long-term effects of PACAP in type II diabetes, we cross-bred PACAP/+ mice with agouti yellow KKAy mice, an obesity-induced type II diabetic model (Iwatsuka et al., 1970), and showed that pancreatic PACAP overexpression attenuated hyperinsulinemia and islet hyperplasia in KKAy mice, without any alteration of plasma glucose, glucose tolerance, or insulin tolerance (Tomimoto et al., 2004). The gene discussed is ADCYAP1; the disease is type 2 diabetes mellitus.