Estrogen Binding in Mammary Tissue of C3H Mice With or Without the Mouse Mammary Tumor Virus

Abstract

Substrains of C3H mice, with and without the milk-transmitted form of the mouse mammary tumor virus (MMTV)¹, were compared to determine if the presence of MMTV altered estrogen action. Uterine weight response to oral diethylstilbestrol was the same for both substrains, (MMTV⁺ and MMTV^-). The concentration of high-affinity estrogen binding sites ("receptors") in lactating mammary tissue did not differ significantly for MMTV⁺ versus MMTV^- mice; the affinity of the estradiol-receptor interaction appeared higher, however, in cytosol from MMTV^- mice. Sucrose density gradient analysis revealed no significant differences in sedimentation properties of cytosol receptor from the two substrains.

Evaluating Mutant Mice: Anatomic Pathology

“…10 11) A high incidence of mammary gland tumors occurred in some C3H strains (e.g., C3H/HeJ and C3H/OuJ) that carried exogenous milk-transmitted murine mammary tumor virus (MMTV) or Bittner agent. 12,33,138 Except where it has been preserved intentionally for experimental purposes, exogenous MMTV probably has been eliminated from most laboratory colonies by rederivation. 12) T-cell lymphoblastic lymphoma (thymic lymphoma) is a common cause of death in AKR mice by 1 year of age, with a peak incidence at 3-6 months, and is attributed to complex interactions between the ecotropic murine retrovirus AKV and other murine retroviruses.…”

“…A high incidence of mammary gland tumors occurred in some C3H strains (e.g., C3H/HeJ and C3H/OuJ) that carried exogenous milk-transmitted murine mammary tumor virus (MMTV) or Bittner agent 12 33 138 Except where it has been preserved intentionally for experimental purposes, exogenous MMTV probably has been eliminated from most laboratory colonies by rederivation.…”