Endocrine System Chapter 23 PDF

Endocrine System Chapter 23 – Part A Sai Sudha Koka, PhD., RPh Associate Professor Department of Pharmaceutical Sciences Irma Lerma Rangel School of Pharmacy Texas A&M University Kingsville, TX 78363 Phone: 361-221-0758 e-mail: [email protected] O...

Endocrine System Chapter 23 – Part A Sai Sudha Koka, PhD., RPh Associate Professor Department of Pharmaceutical Sciences Irma Lerma Rangel School of Pharmacy Texas A&M University Kingsville, TX 78363 Phone: 361-221-0758 e-mail: [email protected] Office: Room 304  Chapter 23 Adrenal glucocorticoids Thyroid hormones Growth hormone Tissue and bone growth Calcium balance  Learning Objectives – Chapter 23 Part A Discuss the anatomy of the adrenal gland. Discuss hormone regulation (CRH, ACTH, and cortisol). Explain the physiological functions of CRH and ACTH. Identify the hallmarks of hypercortisolism and hypercortisolism and explain the possible causes and discuss the therapeutic use of cortisol.  The Adrenal Gland Adrenal cortex secretes steroid hormones, aldosterone (sodium- potassium balance), glucorticoids, sex hormones The paired adrenal glands sit on top of the kidneys. Each region secretes different hormones. Region Secretes Capsule Capsule Zona Aldosterone glomerulosa Adrenal cortex secretes steroid hormones. Zona Glucocorticoids fasciculata Zona Sex hormones reticularis Adrenal medulla Catecholamine Adrenal medulla s secretes catecholamines. The Hypothalamic-Pituitary-Adrenal (HPA) Pathway  Cortisol is Essential for Human Life Cortisol is the main glucocorticoid The control pathway of secretion is the hypothalamic-pituitary-adrenal pathway Continuous secretion, diurnal rhythm Role in the mediation of long-term stress Protective effect against hypoglycemia through permissive effect Metabolic effects Cortisol Immunosuppressant effects – Suppresses the immune system – Inhibits the inflammatory response – For treating bee stings, poison ivy, and pollen allergies – Helps prevent rejection of transplanted organs Exogenous administration may shut down ACTH production and adrenal cells – Producing adrenal cells atrophy Physiological Actions of Cortisol  CRH and ACTH – Physiological Functions Association between stress and the immune function appears to be mediated through CRH and ACTH The CRH family includes CRH and brain neuropeptide urocortin – CRH – Decreases food intake – Association with signals that mark the onset of labor – Links to several mood disorders  Cortisol Iatrogenic Exogenous administration may shut down ACTH production and adrenal cells that produce cortisol atrophy  Cortisol Pathologies Hypercortisolism – Adrenal tumor that autonomously secretes cortisol – Pituitary tumor that autonomously secretes ACTH - Cushing’s disease – Iatrogenic (physician-caused) hypercortisolism Hypocortisolism – Hyposecretion of all adrenal steroid hormones – Addison’s disease - autoimmune destruction of the adrenal cortex Hypercortisolism (Cushing’s Syndrome)  Hypercortisolism Metabolic Effects Promotes gluconeogenesis o cause hyperglycemia – mimics diabetes Breakdown of skeletal muscle proteins Enhances lipolysis o deposit extra fat in trunk and face – in part because of increased appetite and food intake Suppresses the immune system Negative calcium balance Influences brain function o mood elevation followed by depression – difficulty with learning and memory  Addison’s disease Rigdutoa autoimmune destruction of the adrenal cortex  ACTH and Melanocortins POMC (pro-opiomelanocortin) undergoes post-translational processing to produce a variety of biologically active peptides – ACTH and -endorphin, endogenous opioid, are among the peptides produced in the pituitary – Nonpituitary tissues create MSH (melanocyte- stimulating hormone) – -MSH inhibits food intake and acts on melanocytes which contain pigments called melanins Melanocortins are MSH hormones and ACTH – “Tan” color in Addison’s diseases Thank You  Endocrine System Chapter 23 – Part B Sai Sudha Koka, PhD., RPh Associate Professor Department of Pharmaceutical Sciences Irma Lerma Rangel School of Pharmacy Texas A&M University Kingsville, TX 78363 Phone: 361-221-0758 e-mail: [email protected] Office: Room 304  Chapter 23 Adrenal glucocorticoids Thyroid hormones Growth hormone Tissue and bone growth Calcium balance  Learning Objectives – Chapter 23 Part B Describe the synthesis and secretion of thyroid hormones, thyroid hormone control pathway. Identify the hallmarks of hyperthyroidism and hypothyroidism Identify the hallmarks of hypersecretion and hyposecretion of growth hormone in children and adults. Describe the structure of bone and explain the mechanisms by which bone adds diameter and length, including the cells and hormones involved. Explain the physiological functions of calcium, the distribution of calcium in the body and explain the factors that influence its movement between compartments. Describe the endocrine control of plasma calcium concentration by parathyroid hormone and calcitriol.  Thyroid Hormone Synthesis The thyroid gland is a butterfly-shaped gland, located just below the larynx. It secretes thyroid hormones and calcitonin. Larynx Thyroid gland Trachea Pathway of Thyroid Hormone Control Thyroid Hormone Synthesis Thyroid Hormone Synthesis Thyroid Hormone Synthesis Thyroid Hormone Synthesis Thyroid Pathologies  Thyroid Pathologies Hypothyroidism Hyperthyroidism Increase oxygen consumption and metabolic heat Slow metabolic rate and oxygen production consumption Increase protein catabolism may cause muscle Decrease protein synthesis weakness - Myxedema (puffy appearance) Hyperexcitable reflexes and phychological Nervous system changes in adults disturbances ranging from irritability and insomnia to include slow reflexes, slow speech psychosis and thought process, and feelings of fatigue Rapid heartbeat and increase force of contraction - Cretinism in infancy Influence beta-adrenergic receptors of the heart Bradycardia Goiters result from excess TSH stimulation of thyroid gland  Thyroid Pathologies Hypothyroidism Hyperthyroidism Myxedema. In hypothyroid individuals, mucopolysaccharide deposits beneath the skin may cause bags under the eyes.  Thyroid Pathologies Affect Quality of Life Hypothyroidism Hyperthyroidism Primary hypothyroidism is due to Hyperthyroidism lack of iodine in the diet – Thyroid-stimulating immunoglobulins (TSI) mimic Treatment for hypothyroid TSH in Graves’ disease disorder: oral thyroid hormone – Pituitary tumors secreting TSH Treatment: surgical removal of gland, destroy with radioactive iodine or block biosynthesis of hormone Growth Hormone  Growth Hormone Growth is a continuous process Growth rates in children are not steady Normal growth depends on ?? Peak GH release during teenage years Two neuropeptides released: GHRH and somatostatin Role in sleep cycles is unclear – GHRH may have sleep-inducing properties Binds growth hormone–binding protein in blood – May play a role in adult height Stimulates secretion of insulin-like growth factors – Stimulate bone and soft tissue growth with GH – Stimulate cartilage growth Promotes protein synthesis Increases plasma fatty acid and glucose  Growth Hormone GH Deficiency GH Hypersecretion Severe GH deficiency in childhood leads to dwarfism Over secretion of GH in children leads to gigantism Genetically engineered human growth hormone (hGH) raises ethical questions Adults with excessive secretion of GH develop acromegaly – Limited effectiveness and side effects  Tissue and Bone Growth Soft tissue growth versus bone growth Tissue growth requires hormones and paracrine growth factors – GH and IGFs are required for protein synthesis and cell division – Hypertrophy versus hyperplasia – Thyroid hormones play a permissive role – Insulin stimulates protein synthesis and provides energy (glucose) Bone growth requires adequate dietary calcium Bone growth is impacted by hormonal control of calcium homeostasis  Bone Growth Requires Adequate Dietary Calcium Hydroxyapatite is the most common form of calcium phosphate Bones grow when matrix is deposited faster than it is resorbed Outer layer of compact bone and inner layer of spongy trabecular bone – Osteoblasts produce enzymes and osteoid Growth at epiphyseal plates – Chondrocytes lay cartilage, calcify, osteoblasts move in and lay down bone matrix Osteoblasts revert to less active osteocytes – Osteoclasts control resorption or breakdown on bone Bone remodeling Composition of Bone Bone Growth Bone Resorption  Calcium Balance and Function Total body calcium = intake output 1. Total body Ca2+ is distributed among three compartments Extracellular fluid Intracellular Ca2+ Extracellular matrix (bone) 2. Input is the Ca2+ ingested in the diet and absorbed in the small intestines 3. Output occurs primarily through the kidneys Small amount excreted in feces  Calcium and Phosphate Homeostasis are linked Phosphate is the second key ingredient in the hydroxyapatite of bone Phosphates have other significant physiological roles Energy transfer and storage Activation or deactivation of enzymes, transporters, and ion channels Part of DNA and RNA backbone Phosphate homeostasis parallels that of calcium Metabolic disorder in which bone resorption exceeds bone deposition Common in women after menopause Risk factors include small, thin body type, postmenopausal age, smoking, and low dietary Ca2+ intake Maintain adequate dietary Ca2+ intake Perform weight-bearing exercises Hormones Regulating Calcium Balance Three Main Hormones Control Calcium Balance Calcitonin Calcitriol PTH Calcitonin Calcitonin Calcitriol Endocrine Control of Calcium Balance Vitamin D3 Parathyroid Hormone Parathyroid Glands and Parathyroid Hormone (PTH) Thank You