TSH is a glycoprotein hormone, which stimulates the thyroid gland to secrete Triiodothyronine (T3 ) and thyroxine (T4 ). TSH secretion is regulated by negative feedback machanism. It’s release from the anterior pitutary is induced by the thyrotropin releasing hormone (TRH). When thyroxine level in the blood increases, TRH acts on both the pituitary and hypothalamus to inhibit TSH secretion.
Adreno cortico tropic hormone (ACTH): ACTH is a peptide hormone that stimulates the adrenal cortex to secrete glucocorticoids and mineralocorticoids. It stimulates melanin synthesis in melanocytes, induces the release of fatty acids from adipose tissues and stimulates insulin secretion. ACTH secretion is regulated by negative feedback mechanism.
