title: The effect of platelet protein and DNA on the measurement of human lymphocyte beta adrenergic receptor number.
abstract: Considerable variation exists in human lymphocyte beta adrenergic receptor measurements when the data are reported as fmole/mg protein. To investigate potential sources of measurement errors, human lymphocytes were prepared as follows: With the standard method (M1), lymphocytes were removed from heparinized whole blood by centrifugation on a ficoll gradient. The modified method (M2) was identical, except for an initial centrifugation to remove platelet-rich plasma. Beta adrenergic receptors were measured by the binding of [125I] pindolol with the results analyzed by the method of Scatchard. The M1 receptor number was 11.9 +/- 1.8 fmole/mg protein compared to 26.7 +/- 4.1 fmole/mg for M2 (p1/40.01). Since platelet-rich M1 had 71.9 micrograms protein/100 microL of sample and platelet-poor M2 and 23.8 micrograms/100 microL the difference in receptor number is a calculation artifact due to platelet protein. Similar results were obtained when data were expressed as fmole/mg DNA, because platelets also contain nucleic acids. However, when expressed as the number of binding sites/cell, neither platelet protein nor platelet-DNA affected receptor quantitation. We conclude that results are most accurately reported as sites/cell.
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism; D004247:DNA / Q000097:blood; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D010869:Pindolol / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism*
chemical_list: D001798:Blood Proteins; D011943:Receptors, Adrenergic, beta; D004247:DNA; D010869:Pindolol