Hemolytic Properties of Indol

Abstract

Rhoads and his collaborators 1 , 2 , 3 have recently established that the administration of indol to dogs on a deficient (Goldberger) diet results in a severe anemia which can be cured by adding the lacking factors to the diet, and have further shown that this anemia is the result of a hemolytic process rather than of the lack of a growth factor required for normal marrow activity. Because of these observations, the in vitro hemolytic properties of indol are of considerable interest, and these have not hitherto been described.

1. Indol is a weak hemolysin, a system containing 1.6 cc. of 1 mM/1. indol in 1% NaCl (this is a virtually saturated solution, and has a pH of 6.3), together with 0.4 cc. of a rabbit red cell suspension with 2.5 (10⁸) cells per cc., showing complete lysis in about 30 min. at 25°C. Half this concentration, however, does not show complete lysis for many hours. The lytic effect on the cells of man and of the dog are very similar. As in the case of most lysins, the lytic effect is strongly inhibited by serum or plasma, and, again as in the case of most lysins, the hemolysis is preceded by a discsphere transformation. In a saturated solution of indol, this occurs almost immediately.

2. Indol is a powerful accelerator of lysis by saponin, the value of (R-1)/c, which measures the accelerating power, being —0.60; this means that indol is abut 24 times as acceleratory as benzene (millimol for millimol), and about as portent as iodobenzene. The acceleration of taurocholate hemolysis is smaller, viz., —0.20, or abut 8 times that of benzene. These values are at 25°C.