Control of Blood Sugar Diabetes Mellitus
Maintaining Glucose Homeostasis • Goal is to maintain blood sugar levels between ~ 70 and 110 mg/dL • Two hormones play a role in maintaining glucose homeostasis: • Insulin • Glucagon • Both are pancreatic hormones
Lowering Blood Glucose Levels • Blood glucose levels rise due to eating a carbohydrate containing meal • In response, the pancreas releases insulin into the blood. • Beta cells of the pancreas release insulin
Lowering Blood Glucose Levels • Insulin • Binds to insulin receptors on cells. • Cells allow glucose to enter • Stimulates liver and muscle cells to store glucose as glycogen • Stimulates excess glucose to be converted into fat. • As a result, blood glucose levels drop.
Raising Blood Glucose Levels • Blood glucose levels drop as cells use glucose. • In response, the pancreas releases glucagon into the blood. • Alpha cells of the pancreas release glucagon
Raising Blood Glucose Levels • Glucagon: • Stimulates liver cells to break down glycogen and release the glucose into the blood. • As a result blood glucose levels rise.
Diabetes Mellitus • Diabetes mellitus refers to a group of metabolic disorders in which the body is unable to regulate high blood glucose levels.
Diabetes Mellitus • Two common forms: • Type 1 diabetes • Other names: • “Juvenile” diabetes • Insulin dependent diabetes mellitus (IDDM) • Type 2 diabetes • Other names: • “Adult onset” diabetes • Noninsulin dependent diabetes mellitus (NIDDM)
Incidence of Diabetes • Type 1 Diabetes • 5-10 % of diabetics • Onset is generally before age 20 • Average age of onset ~12 • Type 2 Diabetes • 90-95% of diabetics • Onset is generally between ages 10-19 or after age 40
Type 1 Diabetes • Possible causes: • Autoimmune disorder • Genetic component • Immune system destroys beta cells of pancreas • May also be caused by a viral infection that damages the pancreas
Type 1 Diabetes • Pancreas is unable to make/secrete insulin. • Glucose cannot enter cells hunger • Blood glucose levels rise • Glucose “spills” into the urine • Water moves into blood • Frequent need to urinate • Thirsty
Type 1 Diabetes • Cells use fats and proteins as an energy source, results in: • Weight loss hunger • Ketones produced (due to “overuse” of fats for energy) potential for diabetic acidosis
Type 1 Diabetes • Diabetic acidosis (ketosis) • Ketones in breath • Ketones in blood and urine can lead to diabetic coma
Type 1 Diabetes • Treatment • Insulin shots or pump • Highly regulate intake of carbohydrates • Consistent pattern of moderate carbohydrate intake to minimize fluctuations in blood glucose • Closely monitor blood glucose levels
Type 2 Diabetes • Associated with obesity • As gain weight, cells make fewer insulin receptors • Insulin doesn’t bind as well to receptors made • Genetic component • More common as age
Type 2 Diabetes • Fewer insulin receptors on cells • Less insulin binds to cells • Glucose enters cells SLOWLY • Blood glucose levels remain elevated • Glucose “spills” into the urine • Water moves into blood • Frequent need to urinate • Thirsty
Type 2 Diabetes • Glucose enters cells slowly… • No need to use proteins or fats for energy • Hungry • Eat more gain weight • Exacerbates the problem
Type 2 Diabetes • Pancreas continues to make insulin • Often in large amounts to compensate for the insulin resistance of cells • May get to point where pancreas cannot keep up with the body’s needs and insulin is required.
Type 2 Diabetes • Recommendations • Lose weight • Even moderate weight loss can help • Exercise • Increases number of insulin receptors • Improves binding of insulin to the receptors • Helps with weight loss
Chronic Complications of Diabetes • Regular high blood glucose levels result in • Cells making sugar alcohols • Glucose binds to proteins on cells, damages cells • Results in: • Damage to blood vessels and nerves • Slowed healing • Unaware of wounds…… amputation • Kidney damage kidney failure • Damage to cells of eyes blindness
Chronic Complications of Diabetes • Other: • Increased risk of: • Coronary heart disease • Elevated blood lipid levels • Hypertension • Adults with diabetes have heart disease and stroke death rates ~ 2 to 4 times higher than adults without diabetes.
2007 US Data • Total: 7.8% of the population has diabetes • Age 60 or older 23.1% have diabetes • 1 in 6 overweight adolescents aged 12-19 have pre-diabetes • More Statistics
% of people 65 or older with diabetes by race in the U.S. Source: CDC/NCHS