Studies in steroid metabolism. VIII. Steroidogenesis in a heterologous tumor transplant.

Relatively little is known concerning the main tenance of biochemical integrity of tissue after it has been heterologously transplanted. The pos sibility of tissue enzyme adaptation to the new host following such a transplant is not easily ruled out. This subject is of particular interest in view of the use of human tumor transplants in rodents as a screening method for antitumor agents. A recent report from this laboratory (3, 6) described the biosynthesis of androgens, estrogens, and progesterone from a testicular tumor, follow ing incubation of the excised tissue with labeled acetate. By use of a similar procedure, it was possible to demonstrate the formation of testos terone and possibly progesterone, but not estro gen, from a heterologous transplant of a similar tumor (4) which had been retransplanted 21 times.