General
Why is the pancreas considered a compound gland?
Endocrine functions- releasing hormones in blood
Exocrine functions- releasing digestive enzymes in duodenum
What is the marker for insulin levels in human med?
Which hormone is co secreted with insulin?
C-peptide & Amylin
What hormone besides insulin inhibits glucagon secretion directly?
Amylin
What are two major pancreatic dysfunctions?
Insulin excess & insulin deficiency
In a lab setting, if the sample is collected properly how do prevent misdiagnosis?
Centrifuge immediately; place serum in fridge or freezer depending on how long you are waiting
Name the cells within the Islets of Langerhans and the hormone produced.
Alpha cells (glucagon), Beta cells (insulin & amylin), Delta cells (somatostatin), Epsilon cells (ghrelin), and PP/gamma cells (pancreatic polypeptide)
How does insulin lower blood glucose levels?
Stimulate glucose uptake and utilization
What is the target tissue of glucagon? How does glucagon raise BG levels within minutes?
Liver
Via hepatic glycogenolysis and hepatic gluconeogenesis
During insulin excess, what is the typical cause? Consequence? Clinical Signs?
Insulinoma=> tumor producing uncontrolled amounts of insulin
Hypoglycemia->reduced functions
CNS-> delay in response, ataxia
SMS -> fatigue
Which animal are insulinomas common in?
ferrets
What are the functions of somatostatin, amylin and pancreatic peptide?
Influence food intake and absorption; modulating insulin and glucagon release
Which tissues are most dependent on insulin for their glucose uptake?
Muscle & fat
As glycogen storage empty (4-8 hours) which pathway becomes dominant?
Gluconeogenesis
What is the clinical/common name for insulin deficiency? Which do you typically see in which animals?
Diabetes Mellitus
Type 1=dogs
Type 2 = cats
Are insulinomas benign or malignant?
Invariably malignant->can spread throughout entire abdomen
What are insulin's four biological actions across tissues.
1. Glucose uptake into muscle and fat
2. main metabolic functions liver, muscle, and fat tissue
3. regulatory functions in most other tissues
4. electrolyte homeostasis
In electrolyte homeostasis, which electrolyte effects the muscle? Kidney? What serious consequences could the imbalance of these electrolytes have due to dysregulated insulin?
Muscle = potassium - hypokalemia
Kidney = sodium - hypertension
Hypo_______ stimulates glucagon and Hyper___________ inhibits glucagon
Hypoglycemia; Hyperinsulinemia
Describe the difference between Type 1 & Type 2 diabetes. Explain the causes of both.
Type 1: Beta cells become dysfunctional, fail to produce insulin; causes: auto-immune, age, inflammation
Type 2: Insulin resistance develops in tissues, insulin is present but cannot exert its effects fully; Causes: often obesity related
What is a key indicator for insulinoma? Clinical Signs?
Glucose <60 mg/dL with high insulin levels (>20 uU/mL)
Clinical Signs: seizures, ataxia, lethargy, collapse, head-pressing, blindness, tachycardia, polyphagia common
Describe or Whiteboard
Glucose-sensing Mechanism
Glc oxidation-> ATP increases -> closes Katp channels-> K is retained intracellularly->membrane depolarization opens calcium channels-> Ca influx-> exocytosis of granules->release of insulin and C-peptide
Whiteboard insulin synthesis
Check with image in slide
Whiteboard glucagon synthesis
Check with image
During Insulin deficiency, what happens to BG levels? Glucagon? Any other hormones effected?
Sustained hyperglycemia; Glucagon can increase due to the insulin block being gone; Cortisol can increase due to signal of metabolic starvation (no insulin = no glucose uptake by muscles)
How do you tell if hyperglycemia or hypoglycemia is sustained or not?
If fructosamine is low/high along with glucose