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Chapter-24 Regulation of Blood Glucose, Insulin and Diabetes Mellitus

BOOK TITLE: Textbook of Biochemistry for Medical Students

Author
1. Vasudevan DM
2. S Sreekumari
3. Vaidyanathan Kannan
ISBN
9789350250167
DOI
10.5005/jp/books/11359_24
Edition
6/e
Publishing Year
2011
Pages
18
Author Affiliations
1. Faculty of Medicine, Amrita Vishwa Vidyapeetham, (Amrita University), Kochi, Kerala, Formerly Principal, College of Medicine, Amrita, Kerala; Formerly, Dean, Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, Amrita Vishwa Vidyapeetham (Deemed University), Cochin, Kerala, E-mail: dmvasudevan@aims.amrita.edu, PG Programs and Research College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India, College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India; Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, India
2. Jubilee Mission Medical College, Trissur, Kerala, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, Government Medical College, Thrissur and Thiruvananthapuram, Kerala, India; Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India; Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
3. Amrita Institute of Medical Sciences, Kochi, Kerala, India, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India, Believers Church Medical College and Hospital, Thiruvalla, Kerala, India
Chapter keywords

Abstract

Major factors that cause entry of glucose into blood are absorption from intestines, glycogenolysis and gluconeogenesis. Major factors that cause depletion of glucose in blood are utilization by tissues, glycogenesis and conversion to fat. Hyperglycemic hormones are Glucagon, Cortisol, Adrenaline and Growth hormone. Insulin is a hypoglycemic hormone. Indications for an oral glucose tolerance test (OGTT) are; patient with symptoms suggestive of diabetes mellitus, excess weight gain during pregnancy and to rule out benign glycosuria. Contraindications for an OGTT are; known case of diabetes mellitus, to follow prognosis of diabetes mellitus and performing on acutely ill patients. Conditions that can be assessed by OGTT are impaired glucose tolerance, impaired fasting glycemia, gestational diabetes, alimentary glycosuria and renal glycosuria. Reducing substances in urine other than glucose are fructose, lactose, galactose, pentoses, homogentisic acid, salicylates, glucuronides and ascorbic acid. Insulin has the following biochemical effects: increases uptake of glucose by cells, enhances utilization of glucose, hypoglycemic, antilipolytic, antiketogenic and favors lipogenesis. Insulin acts via a specific insulin receptor present on cells of insulin responsive tissues. This affects a signal transduction pathway, which leads to regulation of gene transcription, DNA synthesis and activation of enzymes. Diabetes mellitus is of two types, Type 1 and Type 2. Type 1 is also known as insulin dependent (IDDM), while the type 2 was previously known as non insulin dependent diabetes mellitus (NIDDM) Secondary diabetes mellitus can be; manifested in endocrine disorders (Cushing’s syndrome, Thyrotoxicosis), drug induced (beta blockers, steroids), seen in pancreatic diseases (chronic pancreatitis). Diabetic ketoacidosis (DKA), lactic acidosis and hypoglycemia are acute metabolic complications of diabetes mellitus. Retinopathy, neuropathy and vascular diseases are chronic complications of diabetes mellitus. Glycated hemoglobin (HbA1c) is used as an index for long-term control of blood glucose level.

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