Regulation of Blood Glucose Levels

What part of pancreas secretes insulin and glucagon?

• pancreatic islets

What cell secretes glucagon?

• alpha cells

what cell secretes insulin

• beta cells

What glucose transporter allows glucose to enter beta cells?

• GLUT-2 transporter

How does insulin release occur?

• glucose enters beta cell via GLUT-2 transporter

• results in increase in ATP:ADP ratio

• this increase leads to closure of ATP sensitive K+ channels and membrane depolarisation

• depolarisation causes voltage gated calcium ion channels to open

• increase in cytosolic calcium promotes insulin secretion via exocytosis

What glucose transporter transports glucose into adipocytes and skeletal muscles?

• GLUT-4 transporter

What does glycogen synthase kinase do to glycogen synthase?

• inactivates it

What happens when glycogen synthase is phosphorylated?

What protein prevents this?

• becomes inactive

• PKB (binds to glycogen synthase kinase, stopping phosphorylation from occurring so more glycogen gets made)

What does FOX01 do?

• promotes gluconeogenesis

How does insulin signalling work (the pathway)?

• insulin binds to insulin receptor (IR)

• IR auto phosphorylates

• IRS binds to IR phosphorylated residues

• IRS activates PI3K which converts PIP2 → PIP3

• PIP3 activates PDK1

• PDK1 activates PKB

How does insulin signalling work (the pathway)?

• insulin binds to insulin receptor (IR)

• IR auto phosphorylates

• IRS binds to IR phosphorylated residues

• IRS activates PI3K which converts PIP2 → PIP3

• PIP3 activates PDK1

• PDK1 activates PKB

How does insulin signalling work (the pathway)?

• insulin binds to insulin receptor (IR)

• IR auto phosphorylates

• IRS binds to IR phosphorylated residues

• IRS activates PI3K which converts PIP2 → PIP3

• PIP3 activates PDK1

• PDK1 activates PKB

How does insulin signalling work (the pathway)?

• insulin binds to insulin receptor (IR)

• IR auto phosphorylates

• IRS binds to IR phosphorylated residues

• IRS activates PI3K which converts PIP2 → PIP3

• PIP3 activates PDK1

• PDK1 activates PKB

How does insulin signalling work (the pathway)?

• insulin binds to insulin receptor (IR)

• IR auto phosphorylates

• IRS binds to IR phosphorylated residues

• IRS activates PI3K which converts PIP2 → PIP3

• PIP3 activates PDK1

• PDK1 activates PKB

What does insulin signalling pathway allow to happen?

• it allows for glucose to enter a cell