Role of Insulin in Lipid Metabolism:
Fat cells responds to insulin with in minutes of its administration. There will be reduction in the release of fatty acids from fat stores. At the same time there will be increase in the synthesis of triacylglycerol to increase fat esterification and storage. So overall effect is decrease in fatty acids in blood.
Insulin inhibits an enzyme called ‘lipase’ in fat cells. Lipase function is to breakdown fat and release free fatty acids in to the blood. Once it’s activity is inhibited by insulin, it no longer releases fatty acids from stored fat. Insulin also increases the activity of another enzyme called ‘lipo protein lipase’ in blood vessel endothelial cells. The function of lipoprotein lipase is to synthesize triacylglycerol using free fatty acids. So fatty acid levels are decreased.
So What Happens in Diabetes?
Type 1: In diabetes there is deficiency of insulin. The chylomicrons and VLDL (both are types of lipoproteins in blood that carry triglycerides from intestinal food and liver respectively) are released in to blood waiting for the enzyme lipoprotein lipase to act. Because of insulin deficiency which is needed by it, the enzyme can not function to its full extent. This increases triglycerides in blood causing ‘Hypertriglyceridemia’, a type of high cholesterol state.
Type 2: The above mechanism also operates in type 2 diabetes. In addition there will be some other mechanisms are responsible for hypertriglyceridemia in type 2. In type 2 there is insulin resistance state which is not an ideal condition for the enzyme lipoprotein lipase. And also the type 2 diabetics are obese, where there will be excess VLDL, related to obesity. VLDL is not metabolized completely increasing the levels of ‘Intermediate density lipoproteins’ in the blood. (IDL carries very high cholesterol in them)
Complications of Excess Cholesterol:
Most important complication is atherosclerosis. Atherosclerosis is deposition of lipid in the inner layers of arteries causing thickening and plaque like formation. The plaque can further develop to cause weakening of the artery wall leading to dilatation and rupture of the artery, clot forms on it’s surface which dislodges and cause embolism. These emboli may block the small arteries and cause ischemia of the organ.
When coronary arteries which supply the heart are involved, patient will suffer from heart attacks due to myocardial infarction. When artery is blocked by the growing plaque, which occludes the lumen, then also myocardial infarction may occur.
- Fat Restriction (Cholesterol levels are determined accurately before starting the treatment)
- Exercise (30 – 60 minutes of aerobic exercise, walking etc will be done. Exercise reduce body weight and decrease insulin resistance)
- Controlling Blood Sugar
- Avoiding Alcohol
- Drugs Like Niacin, Gemfibrozil (Good cholesterol and hypertension control is advised in diabetes as the risk of atherosclerosis increased).
Diabetes is a disorder of carbohydrate metabolism caused by relative or complete deficiency of insulin leading to hyperglycemia and in long term many end organ complications like retinopathy, nephropathy, neuropathy and cardiovascular complications.
Type 1 diabetics are more prone for ketoacidosis with high blood glucose levels. They basically depend on insulin treatment when compared to type 2 diabetics. So any stressful conditions and insulin is not adequately adjusted, they are susceptible to diabetic ketoacidosis.
Type 2 diabetics on other hand are more prone for Hyperosmolar nonketotic coma (HONK) than ketoacidosis. This is severe hyperglycemia in the absence of significant ketosis. Precipitating factors are noncompliance with treatment and inability to drink sufficient water to keep up with urinary loss.
Gestational diabetes is glucose intolerance developed in pregnancy. Close monitoring from early weeks of pregnancy is advised for the improved outcome of mother and baby. Fortunately this condition resolves once baby was delivered.
Of course, most known cause of high blood glucose levels (hyperglycemia) is Diabetes. But there are some other clinical conditions that cause hyperglycemia though they are not common like diabetes .
All these needs special investigations, doctors attention and timely treatment. So it is advised to approach your doctor as soon as you are in doubt of something about your health .
1. Cushing’s syndrome : Caused by persistent and inappropriate increase in glucocorticoid hormones. Patients are obese, plethoric face, thin skin that bruises easily, pathological fractures due to osteoporosis.
2. Pheochromocytoma : Excess production of catecholamines by tumors of sympathetic nervous system. Patients have headache, anxiety, palpitations, sweating, hypertension, hyperglycemia.
3. Glucagonoma : They are tumors of pancreas and produces lots of glucagon a hormone that counteracts the actions of insulin. Patients have hypoglycemia with skin rash.
4. Pancreatic conditions like pancreatitis, hemosiderosis etc also cause hyperglycemia due to damage of insulin producing cells in pancreas.
5. Liver diseases like cirrhosis, hemochromatosis.
6. Medications like diuretics, niacin, phenytoin (taken in epilepsy) are also induce hyperglycemia. Discontinuing these drugs bring back normal glucose status.
7. Acute stress : In people with mild carbohydrate intolerance, stressful conditions like infections, myocardial infarction and surgery may cause marked hyperglycemia. Some of these patients will not need therapy once the stressful condition has resolved.
Doctor can differentiate these conditions by running some tests apart from identifying blood glucose levels. For example, there are tests that detect high levels of glucose, cortisol in blood. Investigations like abdominal CT scans, ultrasound can be used to find out any tumors, pancreatic pathology, liver pathology.[tags]diabetes, diabetic,
[tags]diabetes, diabetic, high blood glucose level, insulin deficiency[/tags]