Hypothalamus and Pituitary Gland Hormones

Sample
- The most commonly used sample is serum.
- In some cases, 24 hours urine sample is collected.
Indications
- These hormones are estimated for:
- Diagnostic purposes.
- For a therapeutic reason.
- To evaluate ovulation.
- To evaluate spermatogenesis.
- To treat endometriosis and uterine fibroids.
- To evaluate precocious puberty.
- To treat prostatic carcinoma.
- To find GH deficiency.
Pathophysiology
- The neurons that give rise to hypophysiotropic hormones are themselves influenced by the hypothalamic neurotransmitter like:
- Dopamine.
- Serotonin.
- Norepinephrine.
- Endorphin.
- Acetylcholine.
- These neurotransmitters modify the secretory activity of the anterior pituitary gland.
- Cytokines also modify this neuroendocrine axis.
- The hypothalamic-pituitary-adrenal axis is modified by the interleukin 1 (IL-1), and interleukin 6 (IL-6) which are produced as a result of infection or stress.
Hypothalamus Hormones:
- Corticotropin-Releasing Hormone (CRH).
- This hormone will stimulate the production and secretion of ACTH by the anterior pituitary glands.
- Thyrotropin Releasing Hormone (TRH).
- This hormone stimulates the production and secretion of TSH and prolactin by the anterior pituitary glands.
- Gonadotropin-Releasing Hormone (GRH).
- This hormone stimulates the production and secretion of FSH and LH by the anterior pituitary gland.
- Growth hormone-releasing hormone (GRH).
- This hormone stimulates the production and secretion of GH by the anterior pituitary gland.
- Growth hormone inhibiting hormone (GIH).
- This hormone inhibits the production and secretion of GH and TSH by the anterior pituitary gland.
- Prolactin inhibiting factor (PIF).
- This is considered to be the neurotransmitter that inhibits the production and secretion of prolactin, TSH, FSH, LH, and GH by the anterior pituitary gland.
Anterior Pituitary Gland:
- Adrenocorticotropic hormone (ACTH).
- This hormone stimulates the secretion of cortisol by the adrenal gland.
- Growth Hormone (GH).
- This hormone promotes growth in soft tissue, cartilage, and bone.
- Thyroid stimulation hormone (TSH).
- This hormone stimulates the secretion of the thyroid hormone T3 and T4 by the thyroid gland.
- Prolactin Hormone.
- This hormone main role is in the initiation and maintenance of lactation.
- Prolactin induces ductal growth and the development of the lobular alveolar system and synthesis of milk production.
- Follicle-stimulating hormone (FSH).
- This hormone controls the functional activity of gonads.
- In the male, this stimulates spermatogenesis.
- In female stimulate the growth of ovarian follicles in the presence of LH. This promotes the secretion of estrogen by the mature follicle.
- Luteinizing hormone (LH).
- This hormone controls the functional activity of the gonads.
- In male produces testosterone by the Leydig cells of testes.
- In female leads to release of the ovum from the ovarian follicle which is ripened by FSH.
- It transforms the follicle into a corpus luteum that secretes the progesterone.
Posterior Pituitary Gland:
1. Antidiuretic Hormone (ADH).
- This maintains the water homeostasis.
- It increases water reabsorption by the distal tubules and collecting ducts of kidneys which increases the concentration of urine.
- This also leads to vasoconstriction to increase blood pressure.
2. Oxytocin.
- This will stimulate uterine contraction during labor.
- This may be used to induce labor.
- It helps in the breast for milk release from the mammary ducts.