Tropic hormone
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Tropic hormones are anterior pituitary-secreted hormones that regulate the activity of various endocrine glands.
One example is the thyroid-stimulating hormone (TSH) (produced by the anterior pituitary) and stimulates the thyroid gland to secrete thyroid hormones. It is the thyroid hormones that actually causes metabolic changes in the human body, in this case to increase metabolic rate and body temperature.
Tropic hormones made and secreted by the anterior pituitary include:
- Thyroid-stimulating hormone (TSH) - stimulates the thyroid gland.
- Adrenocorticotropic hormone (ACTH or corticotropin) - stimulates the adrenal cortex.
- Luteinizing hormone (LH) - stimulates the release of steroid hormones in the ovary and testes.
- Follicle-stimulating hormone (FSH) - stimulates the maturation of eggs and sperm.
- Growth hormone (GH or somatropin) - stimulates the release of insulin-like growth factors (IGFs) from the liver and other organs.
- Prolactin (PRL) - stimulates milk letdown in females, and indirectly affects testosterone secretion in males.
The release of tropic hormones is controlled by a class of hypothalamic hormones called releasing hormones, produced in the hypothalamus. For example, Luteinizing hormone releasing hormone (LHRH) from the hypothalamus stimulates the release of LH from the anterior pituitary. Thus, while the anterior pituitary controls hormone release in most somatic endocrine glands, the pituitary itself is controlled by the hypothalamus.