. _:vb6864680 "Why one set of cells should secrete bile, another urea, and so on, we do not know."@en . . _:vb6864681 "Many tumors secrete two or more different hormones."@en . "1" . _:vb6864680 . _:vb6864681 . _:vb6864679 . _:vb6864679 "(physiology, transitive, of organs, glands, etc.) To extract a substance from blood, sap, or similar to produce and emit waste for excretion or for the fulfilling of a physiological function."@en . _:vb6864680 "1842, William Benjamin Carpenter, Principles of Human Physiology:"@en .