Pituitary Hormones College of Dentistry Qassim University First Year Prof. Dr. Nikhat Ahmed Siddiqui College of Medicine, Qumed. (Glandular System)
<ul><li>Course Objectives </li></ul><ul><li>Name the hormones synthesized in and secreted from Anterior and Posterior Pituitary. </li></ul><ul><li>Outline the Chemical Structure and List main functions of Anterior and Posterior Pituitary. </li></ul>
Endocrine hormones hormone receptor Secretion Target cell Adapted from Benjamin co
Hormone types <ul><li>Often amino acid derivatives or peptides. </li></ul><ul><li>Steroid hormones are made from cholesterol . </li></ul>
Regulation of hormone <ul><li>Prohormone/prehormone : precursor molecule, usually inactive and can be modified (often cut) to become active. </li></ul><ul><li>Preprohormone : precursor to prohormone. </li></ul>
<ul><li>So, once a certain amount of hormones are made, they shut off the system producing them! </li></ul>Regulation of Anterior Pituitary
Posterior pituitary <ul><li>Stores and releases 2 hormones that are produced in the hypothalamus : </li></ul><ul><li>- Antidiuretic hormone (ADH) Vasopressin </li></ul><ul><li>- Oxytocin </li></ul>
Hormone Anterior Pituitary Target Chemical Structure Function Adrenocortico -trophic Hormone (ACTH) Adrenals 39 Amino Acids <ul><li>Stimulates the adrenal gland to produce hormones called: </li></ul><ul><li>Cortisol (Glucocorticoid) Aldosterone (Miberalocorticoid) Testosterone (Androgen) </li></ul><ul><li>Dehydroepiandrosterone sulfate (precursor of Estrogen) </li></ul><ul><li>Cortisol promotes normal metabolism , </li></ul><ul><li>maintains blood sugar levels and blood pressure . </li></ul><ul><li>It provides resistance to stress and acts as an </li></ul><ul><li>inflammatory agent . </li></ul><ul><li>It also helps to regulate fluid balance in the body. </li></ul>Thyroid stimulating hormone (TSH) Thyroid Glycoprotein 2 polypeptide chain ( α and β ) Stimulates the Thyroid Gland to secrete its own hormone called Thyroxine (T4). It stimulates the thyroids through G-protein coupled receptors . Another hormone produced from the thyroid is called tri-iodothyronine or T3. Thyroxine controls many bodily functions, including heart rate , temperature ,growth and metabolism. It also helps metabolise calcium in the body.
Anterior Pituitary Hormone Contd; Leutenising Hormone (LH) & Follicle- Stimulating Hormone (FSH) Ovaries (females) Testes (males) Glycoprotein 2 Polypeptide Chain ( α and β ) Control reproduction and sexual characteristics. Stimulate the ovaries to produce Estrogen and Progesterone and the testes to produce Testosterone and sperm. LH and FSH are also known collectively as gonadatrophins . Estrogen helps with growth of tissue of the sex organs and reproductive parts. It strengthens bones and has a positive effect on the heart. Testosterone is responsible for the masculine characteristics including hair growth on the face and body and muscle development. It is essential for producing sperm and strengthening the bones. Prolactin Breasts Protein 198 amino acids S timulates the breasts to produce milk and is secreted in large amounts during pregnancy and breastfeeding. It is however present at all times in both males and females. Growth Hormone (GH) All cells in the body Protein 191 AA In children this hormone is essential for a normal rate of growth . It stimulates the release of IGF-1 (Somatomedin). In adults it controls energy levels and well-being. It is important for maintaining muscle and bone mass and appropriate fat distribution in the body.
Hormone Posterior Pituitary Target Chemical Nature Function Antidiuretic Hormone (ADH) Vasopressin Kidneys Peptide 9 amino acids <ul><ul><li>Controls the blood fluid and mineral levels in the body by affecting water retention by the kidneys ( water reabsorption). </li></ul></ul>Oxytocin Uterus & Breasts Peptide 9 amino acids <ul><ul><li>Affects the uterine contractions in childbirth and the subsequent release of milk for breast feeding. </li></ul></ul><ul><ul><li>labor and delivery, milk </li></ul></ul><ul><ul><li>ejection,(pair bonding ) </li></ul></ul>