Flashcards in Endocrinology - Glucose homeostasis... Deck (65)
Glucose is the sole source of energy for the ________.
What is the range for normal blood glucose?
What are the exogenous sources of glucose?
What are the endogenous sources of glucose?
glycogenolysis and gluconeogenesis
Post-prandially, how long does glucose provide fuel for and for what?
fuel for 4-8 hours of cell metabolism
In the fasted state, what sources maintain normoglycemia?
The endogenous sources
What is glycogenolysis?
breakdown of hepatic glycogen stores into glucose
When are the hepatic glycogen stores exhausted during fasting?
after 2-3 days of fasting
When glycogen stores are depleted in fasted patients, what takes over to maintain normoglycemia?
What is gluconeogenesis?
The formation of glucose from precursors
What are the precurosors for gluconeogenesis?
Amino acids, glycerol, and lactate
Where does gluconeogenesis occur?
Mainly in the liver, but it can also occur in the kidney
Aside from the exogenous and endogenous sources of glucose, what is also required for normoglycemia?
hepatic function/hepatic blood supply and a functioning endocrine system
What does insulin do?
Promote the cellular uptake of glucose, AA, FA, and electrolytes
Promotes the storage of glucose as glycogen
Inhibits lipolysis and subsequent release of FFA into circulation
Inhibits gluconeogenesis and glycogenolysis
Hypoglycemia is when BG falls below what level?
What is the normal response to hypoglycemia?
There is a stimulation of a release of diabetogenic hormones - glucagon, cortisol, catecholamines, and growth hormone (unimportantly progesterone and thyroxine too)
What is the net effect of the diabetogenic hormones?
Promote gluconeogenesis and glycogenolysis, decrease peripheral glucose use, and shut down insulin secretion
What is the net result of the effect of diabetogenic hormones?
to normalize blood glucose levels
What hormones increase BG?
cortisol, epinehrine, glucagon, and growth hormone
What hormone decreases BG?
What can cause hypoglycemia?
Lack of intestinal absorption, lack of hepatic production, endocrine disorders, increased glucose utilization, and miscellaneous
What can cause lack of intestinal absorption of glucose?
severe malnutrition/starvation and severe intestinal disease
What can cause lack of hepatic production of glucose?
Portosystemic shunts, hepatic failure, and glycogen storage diseases
What are the sub-categories of endocrine disorders can cause hypoglycemia?
Lack of diabetogenic hormones or too much insulin
What endocrine disorders can cause lack of diabetogenic hormones?
hypoadrenocorticism - cortisol deficiency
What endocrine disorders can cause the production of too much insulin?
iatrogenic and insulinoma
What can cause increased glucose utilization?
sepsis, pollycythemia, and extreme exertion
What miscellaneous causes can lead to hypoglycemia?
Juvenile hypoglycemia, xylitol toxicity, paraneoplastic, and artifact
What is the pneumonic to remember the eitiologies for hypoglycemia?
SHIN SPLATS - Sepsis, Hunting dog hypoglycemia, Insulin overdose/iatrogenic, Neoplasia, Spurious, Puppy or polycythemia, Liver disease, Addison's disease, Toxin, and Storage diseases