Cbd

Ca2+

o o O secretory granules

glucose glucose-6-P

- pyruvate mitochondrion

FIGURE 21 Regulation of insulin secretion by glucose. (A) "Resting" beta cell (blood glucose <100 mg/dl). ADP/ATP ratio is high enough so that ATP-sensitive potassium channels (ASKC) are open, and the membrane potential is about —70 mV. Voltage-sensitive calcium channels (VSCC) and calcium-sensitive potassium channels (CSKC) are closed. (B) Beta-cell response to increased blood glucose. In response to increased glucose entry and metabolism, the ratio of ADP/ATP decreases, and ATP-sensitive potassium channels close. Voltage-sensitive calcium channels are activated; calcium enters and stimulates insulin secretion. Increased cytosolic calcium inhibits voltage-sensitive calcium channels and activates calcium-sensitive potassium channels, thereby allowing the cell membrane to repolarize and calcium channels to close. Persistence of high glucose results in repeated spiking of electrical discharges and oscillation of intracellular calcium concentrations.

w&r

FIGURE 21 Regulation of insulin secretion by glucose. (A) "Resting" beta cell (blood glucose <100 mg/dl). ADP/ATP ratio is high enough so that ATP-sensitive potassium channels (ASKC) are open, and the membrane potential is about —70 mV. Voltage-sensitive calcium channels (VSCC) and calcium-sensitive potassium channels (CSKC) are closed. (B) Beta-cell response to increased blood glucose. In response to increased glucose entry and metabolism, the ratio of ADP/ATP decreases, and ATP-sensitive potassium channels close. Voltage-sensitive calcium channels are activated; calcium enters and stimulates insulin secretion. Increased cytosolic calcium inhibits voltage-sensitive calcium channels and activates calcium-sensitive potassium channels, thereby allowing the cell membrane to repolarize and calcium channels to close. Persistence of high glucose results in repeated spiking of electrical discharges and oscillation of intracellular calcium concentrations.

Psychology Of Weight Loss And Management

Psychology Of Weight Loss And Management

Get All The Support And Guidance You Need To Be A Success At The Psychology Of Weight Loss And Management. This Book Is One Of The Most Valuable Resources In The World When It Comes To Exploring How Your Brain Plays A Role In Weight Loss And Management.

Get My Free Ebook


Post a comment