Endocrine 4 Flashcards
What are the four major types of cells in the endocrine pancreas?
How does insluin act to lower blood glucose?
- Inhibition of hepoatic gluconeogenesis
- Promotion of hepatic glycogen synthesis
- Increased cellular uptake of glucose by muscles + adipose tissue
How does glucagon activity increase blood glucose levels?
- Promotes gluconeogenesis in liver + muscles
- Promotes glycogenolysis in liver + muscles
How does catecholamine activity increase blood [glucose]?
- Decreases insulin release by pancreatic B-cells
- Increasing liver glycogenolysis
- Increasing pituaritary release of GH
How does GH activity increase blood [glucose]?
Reduces glucose uptake by myocytes and adipocytes
What is a major consequence of glucose homeostasis?
- Major metabolic consequence of inadequate insulin activity is decreased movement of glucose into insulin-sensitive cells - hepatocytes, adipocytes, skeletal myocytes
1) What is diabeties mellitus?
2) How does the pathogenesis of it vary between cats and dogs?
- Diabeties mellitus = a group of metabolic disorders characterised by hyperglycaemia from from defects in insulin secretion and/or action
- Dogs get type 1 - Beta cell destruction leads to insulin deficiency, cats get Type 2 - impaired insulin secretion/insulin resistance
What are the clinicopathologic changes seen as a result of diabetes mellitus?
- Hyperglycaemia - absence of insulin (type 1) or impaired insulin action (insulinresistance - type 2)
- Glycosuria - hyperglycaemia is higher than renal tubular transport maximum
- Hyperlipemia - defective lipoprotein lipase activity due to decreased insulin = defective processing of chylomicrons - increased lipomobilisation
- Ketonemia - ketogenesis occurs in liver - promoted by glucagone + inhibited by insulin
- Increased fructosamine - irreversible non-enzymatic linking of glucose + albumin
- Stress leukogram
- Increased ALP and ALT - hepatic lipidosis
- Hyponatremia + hypcholoraemia - shifiting of H20 from ICF to ECF due to gradient established by hyperglycaemia - osmotic diuresis due to glycosuria
- Proteinuria - associated with urinary tract infections - USG is generally high despite the polyuria because glucose increases it
Descirbe the pathogenesis of the two main ways that diabeties mellitus can arise:
- Autoimmune destruction of B-cells - infiltration of lymphocytes into the islets and antibodies against B-cell + several islet components
- Genetic susceptibility (breed predisposition)
How does hypercortisolism (hyperadrenocorticism) in the dog result in diabeties mellitus?
Causes insulin resistance
What is an example of predipsosing factor for diabeties mellitus type 2 in cats?
Obesity
What species of cat is predisposed to insulin resistance?
Burmese cat
Briefly explain the pathogenesis of diabeties mellitus type 2 within cats:
- Decreased adiponectin: Adiponectin functions to enhance insulin sensitivity and also has antiinflammatory properties
- Leptin resistance: Appetitie supression + modulation of insulin sensitivity
- Increased TNF-a: pro-inflammatory cytokine + has negative influence on insulin singalling
Briefly explain the pathogenesis of B-cell destruction as a result of amyloid deposition:
- Amyloid is normal product of B-cells and is co-secreted with insulin
- Amyloid levels are elevated in conditions associated with insulin resistance
- Amyloid deposits in the islets of the pancreas
What are the main clinical signs that are associated with diabeties mellitus?
- Polyuria
- Polydipsea
- Polyphagia
- Weight loss
- Recurrent cystitis
- Hepatomegaly
- +/- ketotic breath
- Cataracts
- Neuropathy
