The Response of Leukemic Lymphocytes to Cortisol: A Suggested Role of Transcortin

Lymphocytes obtained from patients with chronic lymphocytic leukemia (CLL) respond to the in vitro presence of cortisol by depressed incorporation of precursors into RNA and protein. The decreased incorporation of uridine into RNA is the sum of (1) an inhibition in the synthesis of RNA and (2) an enhanced destruction of newly synthesized RNA. Whereas cortisol was not dependent upon plasma for the manifestation of the above effects, the presence of plasma was an absolute requirement in order for cortisol to have an inhibitory effect on the synthesis of protein. A comparison of leukemic and normal lymphocytes demonstrated that the magnitude of inhibition of precursors into RNA and protein was greater in leukemic cells. Because it is believed that the plasma factor required is transcortin, determination of transcortin levels by cortisolbinding gel filtration technics were performed. These indicated that transcortin levels of CLL plasma were about 50 per cent lower than that of the normal. Consequently, further experiments involving type-specific plasma substitutions were performed. The results obtained from these experiments indicated that the magnitude of the effect of cortisol on the synthesis of lymphocyte protein was directly related to the transcortin level of the plasma employed.