Pitutary I


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Pitutary I

  1. 1. Introduced by: Dr/Abousree El-Lethy بسم الله الرحمن الرحيم <ul><li>Vitamins K and C </li></ul>Block: Head & Neck Structure and Function Biochemistry Lecture: Pitutary hormones
  2. 2. <ul><li>Objectives of pituitary hormones </li></ul><ul><li>Name the hormones synthesized in and secreted from anterior pituitary. </li></ul><ul><li>Name the hormones synthesized in and secreted from posterior pituitary. </li></ul><ul><li>Outline the chemical structure and list the main functions of anterior pituitary hormones. </li></ul><ul><li>Outline the chemical structure and list the main functions of posterior pituitary hormones. </li></ul>
  3. 3. <ul><li>The anterior pituitary synthesizes and secretes important endocrine hormones, such as: </li></ul><ul><li>1-ACTH: adrenocorticotropic hormone </li></ul><ul><li>It is a peptide of 39 amino acids </li></ul><ul><li>Function: ACTH stimulate adrenal cortex to produce: </li></ul><ul><li>Glucocorticoids, like cortisol </li></ul><ul><li>Mineralocorticoids, like aldosterone </li></ul><ul><li>Androgens (male sex hormones, like testosterone </li></ul><ul><li>Stimulates the adrenal cortex to synthesize a precursor of estrogen called dehydroepiandrosterone sulfate </li></ul>
  4. 4. <ul><li>2- TSH: Thyroid Stimulating Hormone (thyrotropin). </li></ul><ul><li>A glycoprotein , with two polypeptide chain (alpha & beta) </li></ul><ul><li>Function: </li></ul><ul><li>TSH stimulates the thyroid gland to secrete thyroxine (T4). </li></ul><ul><li>It does this by binding to transmembrane G-protein-coupled receptors (GPCRs) on the surface of the cells of the thyroid. </li></ul><ul><li>3- PRL: Prolactin </li></ul><ul><li>Prolactin is a protein of 198 amino acids. </li></ul><ul><li>Function: </li></ul><ul><li>During pregnancy: it helps in the preparation of the breasts for future milk production. </li></ul><ul><li>After birth: It promotes the synthesis of milk. </li></ul>
  5. 5. <ul><li>4- GH: growth hormone (somatotropin) </li></ul><ul><li>It is a protein of 191 amino acids </li></ul><ul><li>Function: </li></ul><ul><li>GH promotes body growth by: </li></ul><ul><li>Binding to receptors on the surface of liver cells </li></ul><ul><li>Then stimulates them to release insulin-like growth factor-1 (IGF-1; also known as somatomedin ) </li></ul><ul><li>IGF-1 acts directly on the ends of the long bones promoting their growth </li></ul>
  6. 6. <ul><li>5-FSH: Follicle-Stimulating Hormone </li></ul><ul><li>A glycoprotein of two polypeptide chain (alpha & beta) </li></ul><ul><li>Function: </li></ul><ul><li>In mature females, FSH (assisted by LH) acts on the follicle to stimulate it to release estrogens. </li></ul><ul><li>In mature males, FSH acts on spermatogonia stimulating (with the aid of testosterone) the production of sperm </li></ul><ul><li>6- LH: Luteinizing Hormone </li></ul><ul><li>It also a heterodimeric glycoprotein consisting of two polypeptide chain (alpha & beta) </li></ul>
  7. 7. <ul><li>Function: </li></ul><ul><li>In females (Ovulation): Stimulates the now-empty follicle to develop into the corpus luteum, which secretes progesterone during the latter half of the menstrual cycle. </li></ul><ul><li>In males: stimulating testes to synthesize and secrete the male sex hormone, testosterone. </li></ul><ul><li>7- Alpha Melanocyte-Stimulating Hormone </li></ul><ul><li>It is a protein of 13 amino acids </li></ul><ul><li>Function: </li></ul><ul><li>Effect on melanocytes: skin cells that contain the black pigment </li></ul>
  8. 8. <ul><li>Posterior pituitary hormones </li></ul><ul><li>1- Vasopressin </li></ul><ul><li>Vasopressin is a peptide of 9 amino acids (Cys-Tyr-Phe-Gln-Asn-Cys-Pro-Arg-Gly). </li></ul><ul><li>It is also known as arginine vasopressin (AVP) and the antidiuretic hormone (ADH). </li></ul><ul><li>Function: </li></ul><ul><li>it acts to reduce the volume of urine formed (giving it its name of antidiuretic hormone). </li></ul>
  9. 9. <ul><li>Oxytocin </li></ul><ul><li>It is a peptide of 9 amino acids (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly). Function: </li></ul><ul><li>It acts on certain smooth muscles: </li></ul><ul><li>Stimulating contractions of the uterus at the time of birth; </li></ul><ul><li>Stimulating release of milk when the baby begins to suckle. </li></ul><ul><li>Oxytocin is often given to prospective mothers to hasten birth. </li></ul>