Abstract
Summary
The MtT.F4 “mammo-somatotropic” pituitary tumor, originally induced and maintained in highly inbred Fischer rats by Dr. J. Furth, was successfully transplanted into randomly bred S-D rats. The tumors grew more slowly, the mean latency period was about twice as long (7-8 weeks as compared to 4 weeks), and about 41-60% of the S-D rats developed palpable tumors as compared to 100% in Fischer rats. Neither estradiolnor PM.S and HCG altered tumor incidence in the S-D rats. The MtT.F4 readily transplanted from S-D to S-D rats. As in Fischer rats, large amounts of prolactin, growth hormone and ACTH were secreted by the MtT.F4 in S-D rats, as indicated by intense mammary stimulation; enlargement of the liver, kidneys and spleen; and a 4-6-fold increase in adrenal size. Unlike the Fischer rat, stomach ulcers were found in most Sprague-Dawley rats with successful tumor transplants.
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