Differential responses of carcinogen-induced fibrosarcoma of mice to altered regimes of cold exposure.
The effect of chronic and intermittent cold exposure was studied in benzo(a)pyrene-induced fibrosarcoma of mice. Chronic exposure to 5 degrees C caused decrease in incidence, increase in latent period, and inhibition of tumor growth. Intermittent exposures to +5 degrees C and -10 degrees C induced significant enhancement of tumor growth which increased with the lowering of temperature. Concomitant with the tumor growth alterations, stress reactions assessed by plasma corticosterone levels, differed in these two regimes. The elevation of plasma corticosterone levels correlates with the tumor growth enhancement which is probably mediated by corticosterone-induced immuno-suppression. Inhibition of tumors appears to be a result of adaptation to chronic stress, or metabolic alterations in cold. Physiological alterations of the host, depending upon the nature and duration and severity of the "stress" exposure, determines in our opinion probably the course of neoplastic development.
D000818:Animals; D001564:Benzo(a)pyrene; D003080:Cold Temperature; D003345:Corticosterone / Q000097:blood; D005354:Fibrosarcoma / Q000139:chemically induced*; D007165:Immunosuppression Therapy; D051379:Mice; D013997:Time Factors
D001564:Benzo(a)pyrene; D003345:Corticosterone