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Interpretation of Diodrast Clearances in Man.

1940; SAGE Publishing; Volume: 43; Issue: 1 Linguagem: Inglês

10.3181/00379727-43-11075p

1535-3702

H. L. White, Thomas Findley, John C. Edwards,

Neuroendocrine Tumor Research Advances

A series of diodrast (D) plasma clearances has been carried out on 11 normal human subjects, with plasma iodine (I) levels varying from 0.3 to 55 mg per 100 cc; simultaneous inulin clearances were determined in some cases. Data on distribution of D betwen cells and plasma are also given. 1. Diodrast in cells. The statement of Smith that D is absent from the cells of drawn human blood is confirmed. However, at equilibrium after intravenous administration of D the ratio averages 0.32. It must be emphasized that here, as with the dog (0.62), the cell/plasma D distribution ratio was obtained after in vivo equilibration had been attained. The cell content of D in man is thus about half that in the dog for a given plasma level, after cells and plasma have come into equilibrium in vivo. 2. Diodrast contribution to urine by cells. Magnitude of contribution of D to urine by cells during a renal passage will be determined by, (a) cell content of D and, (b) rapidity with which D passes from cells into plasma on D depletion of the latter. On the first of these points alone, cell contribution of D in man would be about half of that in the dog. Information on the second point has been obtained by observing the cell/plasma D ratio on a falling plasma D level following an equilibration period of a constant plasma D level, i. e., by following the ratio after cessation of sustaining infusion. Such observations on the dog show a constant ratio, i. e., D diffuses from cells into plasma rapidly enough, as plasma D falls, to maintain a constant distribution. With man, on the contrary, the ratio rises rapidly as plasma level falls following cessation of sustaining infusion; it may go from the equilibrium value of 0.32 to as high as 1.20.