Calcium channels play an important role in insulin secretion from pancreatic beta cells, in which two different L-type voltage-dependent Ca2+ channels (VDCC), the beta cell/neuron type and the cardiac type are expressed. The former pre-dominant subtype gene (hCa CN4) consists of 49 exons spanning 120 kilo-bases. The promoter region of hCaCN4 is similar to that of housekeeping gene, which is extremely G+C rich and lacks a TATA-like sequence but has three possible binding regions for transcriptional factor Sp1. Changes of calcium channel mRNA in rat pancreatic islets after glucose infusion are introduced. It is important to investigate variations or mutations in the hCaCN4 gene, causing insufficient insulin secretion, leading to NIDDM.