1 research outputs found
Effects of tamoxifen and CV 205502 on the morphology and the evolution of the noncancerous mouse mammary gland
Tamoxifen (TAM, 0.01 mglanirnal,
three times a week) and the experimental prolactinlowering
CV 205502 (CV, 1 pglanimal, daily)
were administered prophylactically, alone or
combined, to virgin C3HISy mice during the
early period of promotion in this spontaneous
mammary carcinogenesis system (end of 2nd-
5th month of age), in order to study their influence
on the rnorphology and evolution of the noncancerous
mammary gland during therapy and
after treatment cessation. During TAM administration
the epithelial cells of the growing part of the
gland exhibited myoepithelial- and, late in the
treatrnent period, apoptotic-like features instead
of the secretory ones expected, accompanied by
intense basement rnembrane alterations, thickening
of the surrounding connective tissue and arrested
adipocyte maturation. These effects reversed
progressively after drug withdrawal. The epithelial
alterations were more intense and longer lasting in
the TAM+CV-group, while growth arrest of the glands was observed in both groups parallel to the
degree and the duration of these morphological changes.
In these groups, tumor incidence was diminished,
as expected, but the tumors that developed late
after treatment cessation were of low histological
differentiation. The above morphological obsemations
show that TAM inhibits noncancerous mammary gland
growth during the reproductive period by altering
stromal and epithelial differentiation, effects that reverse
progressively after treatrnent discontinuation and are
potentiated by a prolactin-lowering agent in this animal
study