RT Journal Article
SR Electronic
T1 <em>In Vitro</em> Estrogen-like Effects of 7,12-Dimethylbenz(<em>a</em>)anthracene on Anterior Pituitary Dopamine Receptors of Rats
JF Cancer Research
JO Cancer Res
FD American Association for Cancer Research
SP 6434
OP 6437
VO 48
IS 22
A1 Pasqualini, Catherine
A1 Bojda, Florence
A1 Kerdelhué, Bernard
YR 1988
UL http://cancerres.aacrjournals.org/content/48/22/6434.abstract
AB The ability of 7,12-dimethylbenz(a)anthracene (DMBA), a potent inducer of mammary tumors, to mimic short term effects of estradiol (17β-E2) on the anterior pituitary, was tested in vitro. Incubation of anterior pituitaries from ovariectomized rats with DMBA resulted in a marked depletion of membrane dopamine receptors (labeled with [3H] spiperone) and a parallel stimulation of prolactin (PRL) release. Maximal receptor depletion and PRL release were obtained after 15–30 min of incubation with 10-8 m DMBA. These effects were reversible and already significant after a 5-min incubation. Their magnitude, dose dependency, and time course were identical to those reported for 17β-E2. A structurally related noncarcinogenic polycyclic aromatic hydrocarbon, phenanthrene, had no effect on [3H]spiperone binding or PRL release. When DMBA and 17β-E2, at suboptimal concentrations, were simultaneously added to the culture medium, no synergistic effect could be observed. When 10-8 m of both compounds were introduced simultaneously, the decrease in dopamine receptors and the increase in PRL release were not greater than those observed in the presence of 10-8 m of only one compound, indicating that the same mechanism(s) can be involved. These data suggest that DMBA in desensitizing lactotrophs to dopamine and in releasing PRL, by direct estrogen-like actions on anterior pituitary, may provide a hormonal state conducive to tumor development. ©1988 American Association for Cancer Research.