Insulin secretion in mature cells increases vigorously when extracellular glucose concentration rises. Glucose-stimulated insulin secretion depends on Ca²⁺ influx through voltage-gated Ca²⁺ channels. During fetal development this structured response is not well established, and it is after birth that cells acquire glucose sensitivity and a robust secretion. We compared some elements of glucose-induced insulin secretion coupling in cells obtained from neonatal and adult rats and found that neonatal cells are functionally immature compared to adult cells. We observed that neonatal cells secrete less insulin and can not sense changes in extracellular glucose concentrations. This could be partially explained because in neonates Ca²⁺ current density and synthesis of mRNA 1-Ca²⁺ channel subunits are lower than in adult cells. Interestingly, immunostaining for 1B, 1C and 1D subunits in neonatal cells is similar in cytoplasm and plasma membrane, whereas it occurs predominantly in the plasma membrane in adult cells. We also observed that GLUT-2 transporters expression in adult cells is mostly located to the membrane, while in neonatal cells glucose transporters are predominantly in the cytoplasm. This could explain in part the insensitivity to extracellular glucose in neonatal cells. Understanding neonatal cell physiology and maturation contribute toward a better comprehension of type-2 diabetes physiopathology, where alterations in -cells include diminished L-type Ca²⁺ channels and GLUT-2 expression that results in an insufficient insulin secretion.