AJP - Regulatory, Integrative and Comparative Physiology, Vol 259, Issue 3 545-R548, Copyright © 1990 by American Physiological Society
Human serum and plasma have different sources of epidermal growth factor
A. Lev-Ran, D. L. Hwang and D. S. Snyder
Department of Diabetes, Endocrinology, and Metabolism, City of Hope National Medical Center, Duarte, California 91010.
Epidermal growth factor (EGF) was determined by radioimmunoassay in serum,
plasma, and urine of 23 patients undergoing ablative therapy followed by
bone marrow transplantation. The difference between the serum and plasma
values reflected the amount of EGF released from the platelets at the time
of blood coagulation. Platelet-derived EGF strongly correlated with
platelet count (r + 0.850, P less than 0.0001), and the intercept of the
regression line was very close to zero; one platelet contained
approximately 2.5 x 10(-18) g EGF. Correspondingly, when the platelet count
dropped after bone marrow ablation from 222 +/- 97 to 33 +/- 13 x 10(9)/l,
the serum EGF decreased from 603 +/- 222 to 65 +/- 41 pg/ml (P less than
0.0001). Plasma EGF content did not correlate with the platelet count and
did not change significantly after bone marrow ablation (before and after
the ablation, correspondingly, 290 +/- 80 and 332 +/- 99 pg/ml, P = 0.194).
High-performance liquid chromatographic fractionation of serum and plasma
showed different molecular mass distribution of EGF-immunoreactive
fractions. The main molecular mass components of the plasma EGF did not
change after bone marrow ablation. Urine excretion remained unchanged (320
+/- 133 and 314 +/- 173 pmol EGF/mmol creatinine). We conclude that whereas
platelets are the source of serum EGF, the origin of plasma EGF is
different and the search of its origin is warranted.
