Interactions between prolactin and ovarian secretions during mammary tumorigenesis in the mouse.

The plasma levels of ovarian steroids and the steroid binding capacity in the cytosol of mammary glands have been determined in the low-mammary-tumor C3H/f (XVII) mice. Implantation of a pituitary under the kidney leads to an increase of all these parameters as well as a high mammary tumor incidence. Simultaneous administration of the trans isomer of broparestrol (TBP) leads to a decrease of all the parameters.