Selective uptake of (/sup 3/H)arachidonic acid into the dense tubular system of human platelets

Journal Article · Tue Sep 01 04:00:00 EDT 1987 · Blood; (United States)

OSTI ID:5903327

Laposata, M; Krueger, C M; Saffitz, J E

We have used quantitative electron microscopic autoradiography to characterize the subcellular distribution of arachidonoyl phospholipids following brief (5 minutes) exposure of unstimulated human platelets to (/sup 3/H)arachidonic acid. Labeled arachidonate was taken up rapidly and incorporated into phospholipids. Phospholipid radioactivity was preserved and spatially fixed during tissue processing for electron microscopy. Analysis of autoradiographs showed that following a brief exposure to 750 nmol/L (/sup 3/H)arachidonate, there is selective labeling of an internal membrane compartment composed of the dense tubular system and the open canalicular system. The plasma membrane, platelet granules, and nonmembranous cytoplasm were not labeled. Since the open canalicular system is continuous with the plasma membrane and since phospholipids in continuous membranes are freely diffusible, our observations indicate that (/sup 3/H)arachidonate was incorporated into phospholipids within the dense tubular system and not the open canalicular system. Thus, the dense tubular system, known to contain cyclooxygenase activity, incorporates arachidonate selectively following brief exposure to this fatty acid, presumably to concentrate it in proximity to enzymes for icosanoid synthesis.

• Research Organization: Univ. of Pennsylvania, Philadelphia
• OSTI ID: 5903327
• Journal Information: Blood; (United States), Journal Name: Blood; (United States) Vol. 70:3; ISSN BLOOA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ARACHIDONIC ACID
AUTORADIOGRAPHY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BODY FLUIDS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
DISTRIBUTION
ELECTRON MICROSCOPY
ENZYME ACTIVITY
ENZYMES
ESTERS
LABELLED COMPOUNDS
LIPIDS
MAMMALS
MAN
MATERIALS
MEMBRANES
METABOLISM
MICROSCOPY
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXIDOREDUCTASES
OXYGENASES
PHOSPHOLIPIDS
PRIMATES
SUBCELLULAR DISTRIBUTION
TRITIUM COMPOUNDS
UPTAKE
VERTEBRATES