Which one of following is not a endocrine gland?

Answer: Option D

Endocrine glands are the ductless glands that secrete their products into bloodstream from where they are carried to the target organs. Pancreas, testes and thymus are endocrine glands as they secrete hormones. Pancreas secrete insulin and glucagon, testes secrete testosterone and thymus secrete thymosin hormone. Liver is not an endocrine gland instead, it is a digestive organ which secretes bile juice which is necessary for emulsification of fats.