The present invention relates to an isolated transgenic pig beta cell wherein the PKC and the PKA pathway are constitutively activated; to a transgenic pig islet comprising said transgenic pig beta cell; and to a transgenic pig comprising said transgenic pig beta cell or said transgenic pig islet. Another object of the invention is a device comprising a transgenic pig beta cell or a transgenic pig islet of the invention. The present invention also relates to the use of said transgenic pig beta cell, said transgenic pig islet, or said device for treating a disease, disorder or condition related to the impaired function of endocrine pancreas or of beta cell.