thyroid-stimulating hormone

thyroid-stimulating hormone A hormone that is produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. Abbreviated TSH. TSH promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When the amount of thyroid hormones is excessive, the pituitary gland stops producing TSH, thus reducing thyroid hormone production. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood. Also known as thyrotropin.