Phosphoinositide turnover in human platelets is stimulated by albumin.
The effect of human serum albumin (HSA) on the hydrolysis of phosphatidylinositides in human platelets labeled with myo(3H)inositol was studied. Incubation of platelets with HSA (4 gm/dl) for 10 seconds increased IP2, and IP3, by 169% and 217% respectively. 93% of IP3 accumulated within the first 10 seconds. This effect was also shared by bovine serum albumin, although no changes in IP3 levels occurred with ovalbumin. All albumin species used induced 45Ca+2 release from platelets irrespective of its effect on IP3 accumulation. These findings indicate that albumin may function in biological systems by inducing intracellular signaling.
Amin
R M
RM
Department of Medicine, Uniformed Services, University of the Health Sciences, Bethesda, Maryland.
Hays
J H
JH
Mohamed Shakir
K M
KM
D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D006801:Humans; D006868:Hydrolysis; D007294:Inositol / Q000097:blood; D007295:Inositol Phosphates / Q000097:blood; D010047:Ovalbumin / Q000494:pharmacology; D010716:Phosphatidylinositols / Q000097:blood*; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism / Q000494:pharmacology*; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D015398:Signal Transduction
D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D007294:Inositol; D010047:Ovalbumin; D002118:Calcium