Endocrine Pancreas II Flashcards
How does carbohydrate metabolism affect insulin?
decreases blood glucose
increases glucose transport into muscle and adipose
promotes glycogen formation in liver and muscle
inhibits gluconeogenesis and glycogenolysis
Insulin also aids in _______ of glucose in the liver for glycogen storage. Also keeps it from leaving the cell
phosphorylation
How does lipid metabolism affect insulin?
inhibits mobilization of oxidation of fatty acids
inhibits ketogenesis in liver
promotes ffa storage as triglycerides
inhibits ffa uptake in muscle (in favor of glucose)
inhibits lipolysis
What is ketogenesis? What does it produce
breakdown of fatty acid and ketogenic amino acids to supply energy during fasting
produces ketone bodies
What enzyme increases with ffa storage as triglycerides? Where?
lipoprotein lipase
adipose
When you inhibit lipolysis with insulin secretion, you inhibit _________
hormone-sensitive lipase
How does protein metabolism affect insulin?
ANABOLIC!
decreased blood amino acids
increase aa and protein uptake by tissues
increase protein synthesis
inhibit protein degredation
What are other action of insulin?
promotes K+ uptake into cells
promotes phosphate, Mg2+ uptake into cells
decrease appetite
Insulin [increases/decreases] appetite via the ________
decreases
satiety center of hypothalamus
What does excess insulin cause?
hypoglycemia
What does hypoglycemia stimulate?
cortisol release to stimulate appetite
What happens in insulin resistance?
insulin over-produced (because of high blood glucose which stimulates the release in pancreas, beta cells, remember)
blood insulin and glucose remain high
Why is insulin over-produced with resistance? It helps protect….
during acute illness
preserve brain’s glucose supply
Why is there insulin resistance?
decrease number of receptors
decreased affinity of receptors for insulin
What effect does insulin have on ffa storage in adipose tissue?
increases
What are som other causes of insulin resistance?
hormones
obesity
liver or kidney failure
sepsis
insulin antibodies
T/F: It is completely normal to have short-term insulin resistance due to hormones
TRUE!
What happens in obesity with insulin resistance?
get impaired insulin signaling
decrease inGLUT 4 receptor expression in adipose tissue
What happens with skeletal muscle regarding insulin resistance in obesity?
GLUT 4 expression is normal but decreased transport due to translocation/docking/fusion of GLUT 4 into membrane
What happens with liver or kidney failure with insulin resistance?
suggested there are circulating factors in blood of uremic patients that disrupt insulin signaling
What is type 1 diabetes mellitus?
insulin deficiency
destruction of beta cells, usually due to autoimmune process
What is type 2 diabetes mellitus?
insulin resistance (cells not responding normally)
What is type 2 diabetes?
insulin resistance can be associated with down-regulation of insulin receptors in muscle and adipose tissues or issues with insulin signaling
What is insulinoma?
excessive insulin production by beta-cell tumor
What results in a lack of insulin?
hyperglycemia
hyperlipidemia
peripheral tissue protein catabolism
What is responsible for most of fasting hyperglycemia?
increased hepatic output
What does increased hepatic output lead to with a lack of insulin?
gluconeogenesis increases
uses glucogenic amino acids and glycerol (associated with increased glucagon)
List the effects of hyperglycemia with decreased insulin
increased hepatic output in type 2 diabetes
cells starve
blood hyperosmolality
osmotic diuresis in kidneys
What happens with osmotic diuresis in kidneys?
glucose spilling into urine, water follows
What happens in hyperlipidemia with decreased insulin?
increased oxidation of fat - due to increased lipolysis
fat accumulation in liver
Fatt accumulation in the liver has what effects regarding low insulin with hyperlipidemia?
increase free fatty acids
increase keto acids
overwhelm liver (fatty)
What happens in peripheral tissue protein catabolism with low insulin action? Why?
muscle wasting
weight loss
due to gluconeogensis and LOW amino acid uptake by cells
[Insulin/Glucagon] sequence is identical in ALL species
glucagon
What stimulates glucagon release?
hypoglycemia
protein/aa - stimulates liver to take up aa for fasting
fasting
stress (especially infection)
intense exercise
cholecystokinin
What inhibits glucagon secretion?
glucose
insulin
somatostatin
How does glucagon act?
works through stimulation of a G-protein/cAMP to mediate effects
What are the effects of glucagon?
increases glycogenolysis, gluconeogenesis, lipolysis, ketoacid formation
Does glucagon have effect on glucose utilization by peripheral tissues?
Not really - little to no effect
What is glucagonoma?
tumor of alpha-cells in pancreas
results in diabetes mellitus and necrolytic migratory erythema
What are the pathophysiology associated with glucagon?
glucagonoma
hyperglucagonemia/diabetes mellitus associated with infection
What is hyperglucagonemia/diabetes mellitus associated with infection?
glucagon:insulin ration increased
Somatostatin is secreted by _______
delta cells in pancreas
hypothalamus
GI cells
Somatostatin is stimulated by
all nutrients, inhibited by insulin
Somatostatin is inhibited by
insulin
Somatostatin inhibits
insulin and glucagon
GI hormones
GI motility, enzymes, gastric acid secretion
SS-28 is ___
GI stomatostatin
SS-14 is ____
pancreatic & hypothalamic
List some hormones of adipose tissue?
leptin
tumor necrosis factor-alpha
adiponectin
Define leptin
inhibits appetite by inhibiting neuropeptide Y
increases basal metabolic rate
resistance can contribute to obesity
- an adipose tissue hormone
What is adiponectin?
improves insulin sensitivity
Adiponectin improves insulin sensitivity by ______
increasing tyrosine phosphorylation of insulin receptor
[High/Low] adiponectin has a low risk of type 2 diabetes, and [high/low] adiponectin increases risk of obesity and diabetes (cats)
low
high
