An increase in phosphatidic acid in the absence of changes in diacylglycerol in human platelets stimulated with ADP.
1. ADP caused an increase in radioactivity of phosphatidic acid but not diacylglycerol in human platelets labelled with [3H]arachidonic acid. 2. The radioactivity of phosphatidic acid was significantly increased 10 sec after adding 10 microM ADP and this increase did not depend on production of thromboxane A2. 3. Thrombin (1 U/ml) caused an increase in both diacylglycerol and phosphatidic acid, the latter being much greater than that caused by ADP. 4. The results confirm that ADP stimulates phosphatidic acid production and suggest that a weak stimulus of the phosphatidyl inositol cycle, such as ADP, does not cause accumulation of diacylglycerol.
Duncan
E M
EM
Haematology Division, Institute of Medical and Veterinary Science, Adelaide, Australia.
Tunbridge
L J
LJ
Lloyd
J V
JV
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D016718:Arachidonic Acid / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D004075:Diglycerides / Q000096:biosynthesis*; D006801:Humans; D066298:In Vitro Techniques; D010712:Phosphatidic Acids / Q000096:biosynthesis*; D010974:Platelet Aggregation; D013917:Thrombin / Q000494:pharmacology; D013928:Thromboxane A2 / Q000096:biosynthesis; D014316:Tritium
D004075:Diglycerides; D010712:Phosphatidic Acids; D014316:Tritium; D016718:Arachidonic Acid; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D013917:Thrombin