The Endocrine Pancreas

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The Endocrine Pancreas

• Felix E. Grissom, Ph.D.
• 2219 Numa P.G. Adams Bldg
• Howard University
• Tel. [phone]

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Pancreatic Hormones, Insulin Glucagon Regulate
Metabolism

• Beta cells produce insulin cellular uptake of
  blood glucose
• Alpha cells produce glucagon ? blood glucose
  (from cells)
• D cells produce somatostatin ? gastric secretion

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Pancreatic Hormones, Insulin Glucagon Regulate
Metabolism
Figure 22-7 b The endocrine pancreas
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Islet of Langerhans Crosssection

• Three cell types are present, A (glucagon
  secretion), B (Insulin secretion) D
  (Somatostatin secretion)
• A D cells are located around the perimeter
  while B cells are located in the interior
• Venous return containing insulin flows by the A
  cells on its way out of the islets

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Pancreatic Hormones, Insulin Glucagon Regulate
Metabolism
Figure 22-8 Metabolism is controlled by insulin
and glucagon
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Insulin Action on Cells Dominates in Fed State
Metabolism

• ? glucose uptake in most cells
• (not active muscle)
• ? glucose use storage
• ? protein synthesis
• ? fat synthesis

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Insulin Action on Cells Dominates in Fed State
Metabolism
Figure 22-10 Insulins cellular mechanism of
action
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Insulin Summary and Control Reflex Loop
Figure 22-13 Fed-state metabolism
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Glucagon Action on Cells Dominates in Fasting
State Metabolism

• Glucagon prevents hypoglycemia by ? cell
  production of glucose
• Liver is primary target to maintain blood glucose
  levels

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Glucagon Action on Cells Dominates in Fasting
State Metabolism
Figure 21-14 Endocrine response to hypoglycemia
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Diabetes MellitusAbnormally Elevated Blood
Glucose (Hyperglycemia)

• Type 1 beta cells destroyed- no insulin
  produced?chronic fasted state, "melting flesh",
  ketosis, acidosis, glucosurea, diuresis coma

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Diabetes MellitusAbnormally Elevated Blood
Glucose (Hyperglycemia)
Figure 22-15 Acute pathophysiology of type 1
diabetes mellitus
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Diabetes Mellitus Type II a Group of Diseases

• Over 15 million diabetics in USA- 10 type I, 90
  type II
• Insulin resistance keeps blood glucose too high
• Problem with receptors, glucagons levels
• Chronic complications atherosclerosis, renal
  failure blindness

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Diabetes Mellitus Type II a Group of Diseases
Figure 22-16 Normal and abnormal glucose
tolerance tests