Diseases of Glucose Regulation: Diabetes and Hypoglycemia Flashcards
What defective receptor results in Leprechaunism
•Defective Insulin Receptor (IR) – leads to elf like features
why is the heterozygous form of Leprechaunism less severe
•Heterozygous form is less severe because Leprechaunism is a recessive disorder of the insulin receptor – people who are heterozygous are free of disease however some people with leprechaunism, sometimes carry another mutation of the insulin gene (compound heterozygosity) and they show symptoms – that will vary depending on how damaged the insulin receptor is
Difference between type 1 and 2 diabetes in terms of symptoms vs not
- Type 1: Excessive hunger with weight loss and never asymptomatic
- Type 2: associated with obesity so need for diet and exercise and can often be asymptomatic
Type 1 diabetes (5%)
- what is it
- old name
- common cause
- treatment / cure?
- factors contributing
Is a chronic condition in which the pancreas produces little or no insulin. Insulin is needed to allow glucose to enter cells to produce energy
•Used to be called juvenile diabetes or insulin-dependent diabetes
•No insulin producing B cells; most commonly caused by autoimmune disease specifically destroying B cells in the pancreas
•Must be treated with insulin (injections/pumps) or hyperglycemia and eventually coma
-Type 1 diabetes has no cure – treatment focuses on managing blood sugar levels with insulin, diet and lifestyle to prevent complications
•Different factors including genetics and some viruses may contribute to type 1 diabetes. Although type 1 usually appears during childhood / adolescence it can develop in adults
Type 2 diabetes (90%)
- insulin present?
- potential causes (5)
•Insulin present but target cell resistant several potential causes
- Receptor insensitive or downregulated by hyperinsulinisms (both associated with obesity; reversible; common; also could be caused by pregnancy)
- Receptor defective (Leprechaunism – extreme insulin resistance)
- Ab against receptor blocks insulin (extreme insulin resistance)
- Signal pathway defective
- Poor response of target organ due to obesity, liver disease and muscle inactivity
Treatment of type 2 diabetes - general and obese vs. non-obese
•Healthy diet and exercise most important plus stress reduction and quality sleep
- Obese: lose weight – regulate carb intake
- Non Obese: avoid fasting and hyperglycemia
Treatment of type 2 diabetes in terms of drugs (3)
- Drugs that lower glucose production in the liver and improve sensitivity to insulin
- Drugs that stimulate insulin secretion – major side effect is hypoglycemic
- Drugs that affect glucose absorption in the intestine (e.g. use incretin GLP-1 to increase insulin and lower glucagon and slow gastric emptying that can be helpful in controlling glucose levels
what is lipogenesis
store fat; happens when we eat sugar
sugar tolerance for healthy people can be impaired by what
a low carb, high fat diet
•A low carbohydrate high fat diet is associated with weight gain and does not improve glucose tolerance, insulin secretion or B-cell mass.
Why Proper Diet and Exercise Are So Effective for Type 2 Diabetes (4 points)
- Type 2 diabetes is related to an insulin resistance which often develops over time due to chronic high blood glucose and overproduction of insulin
- Healthy diet and exercise can improve insulin sensitivity and glycemic control
- Eating complex carbohydrates as opposed to simple carbs and avoiding high sugar, high fat diet can help moderate rises in blood glucose levels and keep fat stores at a healthy level
- Exercise expends energy which will help to use up the extra blood glucose and keep a healthy balance of fat cells
Hypoglycemia
- when does it occur in diabetics
- what does it cause
•Hypoglycemia occurs in diabetics when a treatment to lower elevated blood glucose inaccurately matches the body’s physiological need and therefore causes the glucose to fall to a below-normal level; causes organ and brain damage without treatment
in what situations is GLUT-1 upregulated vs downregulated
- Hyperglycemic = too much glucose and get downregulation of GLUT-1
- Normal = appropriate amount of glucose and transported across blood-brain barrier and delivered to neurons
- Hypoglycemic = upregulation of GLUT-1 when too little glucose so that brain gets what it needs but the rest of the body does not
Hypoglycemic unawarness
•desensitization to hypoglycemia so defenses are down (insulin, glucagon, epinephrine response attenuated) brain got sugar it needed and can’t tell there is a problem
Glucose regulation with food intake (5 steps)
Food intake: body needs to get glucose out of blood and into cells fast or dangerous – diabetes occurs if insulin not working and can bring about lethal coma
- Insulin released plus release GLP-1 and GIP from gut (incretins) further increase insulin signalling glucose storage, glycogenesis
- GLP-1 slows gut emptying increasing absorption; in brain inhibits food intake; in liver and pancreas inhibits glucagon; insulin also inhibits glucagon
- Many other factors and complex interactions
- Within a few minutes’ insulin mostly degraded by insulinases or receptor internalization
- Eventually blood glucose drops then increase glucagon promoting glucose out of storage to provide you energy by glycogenolysis and if over 3 hours also gluconeogenesis; glucagon also upregulates somatostatin and insulin which inhibits itself while at the same time activating its own alpha cells
Glucose regulation with exercise
increase glucagon; need energy so breakdown storage products like carbs i.e. increase blood glucose, breakdown protein and fat too
