What gland secretes hormones without the use of a duct?

Answer 1

ALL hormones by definition are secreted directly into the blood stream (and hence without the use of a duct). Glands that produce them are called endocrine glands. Major endocrine glands include the pituitary, thyroid, adrenal and pineal glands. Glands such as the pancreas have a "dual" function in that they secrete via a duct (exocrine function) as well as secreting hormones (endocrine function).

Answer 2

Thyroid, parathyroid, pituitary, thymus