Abstract
Leukaemogenesis induced with chemical carcinogens and hormones was studied in intact and ovariectomized mice of the ICRC strain which is susceptible to spontaneous development of both breast cancer and leukaemia and the Strong A strain susceptible only to breast cancer and not to leukaemia. In ovariectomized females oestradiol was administered at two dose levels (i) 1 μg oestradiol/day for 30 days, (ii) 10 μg oestradiol/day for 30 days. The effect of oestradiol (1 μg/day) and progesterone (1 mg/day) for 30 days was also studied. In one group, two pituitaries of the syngeneic male mice were implanted subcutaneously on the right inguinal pair of mammary glands. Enhancing effect of 20-MCA on leukaemogenesis was seen in intact strain ICRC mice and not in ovariectomized mice. However, administration of hormones, either oestradiol alone or in combination with progesterone, or by the way of pituitary grafts, to these carcinogen treated ovariectomized females increased the incidence of leukaemia with a shorter latent period. Although 20-MCA could induce leukaemogenesis in Strong A ovariectomized females, further treatment with hormones, either with pituitary graft or with oestradiol, failed to promote leukaemogenesis. The highest leukaemia incidence in strain A ovariectomized females was observed in the group treated with a balanced dose of oestradiol and progesterone. The present experimental findings in the ICRC and Strong A strains suggest specific differential responses of different strains of mice to the action of carcinogen and hormones for the induction of leukaemogenesis.
Highlights
BIOLOGICAL studies of mouse strain ICRC, developed at the laboratories of the Cancer Research Institute, Bombay, have established susceptibility of this strain for two spontaneous lesions, mammary cancer and lymphocytic leukaemia, both being of viral aetiologv
The ICRC ovariectomized mice were used for further studies of hormonal factor in experimental induction of mammary cancer and leukaemia
In the present series of experiments, treatment with the carcinogen increased the incidence of leukaemia in ICRC intact virgins having endogenous levels of ovarian hormones
Summary
BIOLOGICAL studies of mouse strain ICRC, developed at the laboratories of the Cancer Research Institute, Bombay, have established susceptibility of this strain for two spontaneous lesions, mammary cancer and lymphocytic leukaemia, both being of viral aetiologv. In the ovariectomized females the breast cancer is totally controlled (Ranadive and Kanekar, 1963; Ranadive and Karande, 1970; Karande, Sheth and Ranadive, 1970) and the acceleration of leukaemogenesis is noted in old animals The ICRC ovariectomized mice were used for further studies of hormonal factor in experimental induction of mammary cancer and leukaemia. The strain Strong A, showing characteristic responses to hormonal factor and chemical carcinogens (Ranadive and Waravdekar, 1955; Ranadive and Hakim, 1958; Ranadive and Karande, 1963; Karande, Mistry and Rangan, 1968) was used for comparative studies. The present communication reports studies of the effects of hormones on experimental induction of leukaemia in strains ICRC and Strong A
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
