Glucagon Hyperglycemic – Glycogenolytic factor (HGF) • Produced by α-cells of islets of Langerhans of Pancreas and act antagonistic to insulin • Involved in – Rapid mobilization of hepatic glycogen to glucose • By Glycogenolysis
Diabetes Mellitus (DM) • DM is a metabolic disease characterized by severe hyperglycemia – Persistently high blood glucose level leads to various long term complications • Diabetes is broadly divided into – Insulin dependent diabetes mellitus (IDDM) – Non-Insulin dependent diabetes mellitus (NIDDM)
Insulin • Polypeptide hormone secreted by beta cells of islet of Langerhans in pancreas – First hormone to be identified, isolated, purified and produced by recombinant DNA technology • Anabolic hormone; influences the metabolism of – Carbohydrate – Fats and – Proteins
Parathyroid Hormone • Two pairs of small oval shaped parathyroid glands located on the posterior of thyroid gland • Primarily concerned with Ca 2+ and PO 4 3 homeostasis through its secretion (parathormone) • Parathormone (PTH): • Secreted by Chief cells of the parathyroid gland – Most important regulator of calcium and phosphorus concentration in extracellular fluid • Chemistry: • Linear polypeptide hormone with 84 amino acids – Alanine is present at N-terminal – Glutamine is present at C-terminal • Aminoacid sequence 1 to 34 is important for its biological activity – Possesses receptor binding properties • Methionine is necessary for calcium mobilizing effects Biosynthesis: • PTH is originally synthesized as a pro-hormone in the chief cells – ...
Thyroid Hormones • Thyroid gland is a bow shaped bi-lobular gland located below the larynx on each side of trachea • Each lobule of thyroid gland consist of a large number of thyroid follicles – Structural and functional unit of thyroid gland • Thyroid follicle are spherical units filled with colloid and made up of cuboidal cells called follicular cells • In between thyroid follicles, small C cells are also present called parafollicular cells • It functions under the influence of TSH from pituitary gland. • Major hormones secreted by thyroid gland are – Thyroxine (T 4 or Tetra iodo thyronin) and Tri iodo thyronin (T 3 ) secreted by follicular cells – Calcitonin secreted by parafollicular cells • Calcitonin is involved in Ca 2+ homeostasis while other two regulate metabolic rate of the body...