Regulation of Blood glucose Flashcards
how is dietary glucose absorbed?
GLUT-1 transporter (luminal side of mucosal cell membrane)
when BGL are high and insulin is secreted from beta cells of pancreas, where does the insulin bind?
insulin receptors (tyrosine kinase) on cell membranes
what is the fate of dietary glucose in liver?
activates GK in glycolysis
stimulate glycogenesis - activates glycogen synthase
oxided by liver for its energy needs - liver glycolysis
what is the fate of glucose in the peripheral tissues?
GLUT 4 in adipocytes and muscle
stored as glycogen in muscle
stored as TAG in adipose
how does glucose enter neurons?
GLUT 1 and 3
how does glucose enter RBCs?
GLUT 1
in what state is glycogen synthase active?
dephosphorylated state
when should post prandial BGL be measured after a meal and what should it be about?
2 hours after meal
<140 mg/dl
when should fasting BGL be taken and what should it be about?
8-10 hours after the last meal
<126 mg/dl
after BGL are low and the alpha cells of the pancreas secret glucagon, what does glucagon bind to?
cell surface receptors
activates adenylyl cyclase which increases cAMP
cAMP activates protein kinase A
which results in phosphorylation of regulatory enzymes (glycogen phosphorylase) - covalent
modification
inhibit glycogen synthase
what happens with glycogen phosphorylase and glycogen synthase with high levels of glucagon int he liver?
glycogen phosphorylase is active on phos (cov modification)
glycogen synthase is inactive on phos (rapid effect)
what happens to gluconeogenesis in liver with high levels of glycogen?
becomes active (slower effect)
what is similar to glucagon?
epinepherine
what maintains BGL in the initial hours of fasting>
glycogenolysis
what happens when you are insulin and you want to decrease BGL
no glycogenolysis - shut it down
no gluconeogenesis
no ketogenesis
no lipolysis
