Enocrine glands are glands that secrete their product (hormones) directly into the blood rather than through a duct. This group contains the glands of the Endocrine system. The main Endocrine glands include the pituitary gland, the pancreas, the testes, the thyroid gland and the adrenal glands. Other organs which are not so well known for their endocrine activity include the stomach, which produces such hormones as ghrelin.