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CASE FILES: BIOCHEMISTRY
A N SW E R S TO C A SE 20: A C U T E FATTY L IV E R
IN PR E G N A N C Y
Summary:
21-year-old female at 35-week gestation with malaise, nausea and
vomiting, jaundice, elevated blood pressures, elevated liver function tests, coagu-
lopathy, hypoglycemia, and subsequently hepatic coma and renal failure. She has
been diagnosed with acute fatty liver of pregnancy.
Associated biochemical defect: Fetal deficiencies of long chain
3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD).
Cause of hypoglycemia: Decreased liver glycogen after liver undergoes
fatty infiltration and subsequent liver failure. Histology reveals swollen
hepatocytes in which the cytoplasm is filled with microvesicular fat.
C L IN IC A L C O R R E L A T IO N
Acute fatty liver of pregnancy is a poorly understood condition affecting only
pregnant women with the clinical manifestations of hypoglycemia, liver fail-
ure, metabolic acidosis, renal failure, and coagulopathy. Affected patients may
become jaundiced or encephalopathic from liver failure, usually reflected by
an elevated ammonia level. Profound hypoglycemia is common. The mortal-
ity rate is approximately 10 to 15 percent. Management is delivery, with sup-
portive measures such as magnesium sulfate to prevent seizures, replacement
of blood or clotting factors, and management of the blood pressure. The patho-
physiology may be related to fetal deficiencies of long chain 3-hydroxyacyl-
coenzyme A dehydrogenase (LCHAD).
A PPR O A C H TO G L Y C O G E N A N D C A R B O H Y D R A T E
M E T A B O L ISM
O bjectives
1.
Know about glycogen storage, synthesis, and degradation.
2.
Be familiar with the regulation of glycogen synthesis and degradation.
3.
Understand the role of liver glycogen in carbohydrate metabolism.
D efinitions
GLUT 2: Glucose transporter isoform 2, a facilitative glucose transporter
present in the liver, the P-cells of the pancreas, and the basolateral sur-
face of intestinal epithelial cells.
Adenylate cyclase: The enzyme that, when activated by hormones bind-
ing to receptors, catalyzes the cyclization of adenosine triphosphate
(ATP) to cyclic adenosine monophosphate (cAMP) with the release of
pyrophosphate.
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