Spontaneous tumors in aging female mice are more prevalent in the lateral pituitary zones.
The localization of gross and microscopic spontaneous pituitary tumors was examined in aging female C57BL/6J mice. These tumors were lactotroph adenomas, by morphological and immunocytochemical criteria. Each lobe of the pars distalis was divided into three zones of approximately equal size and the number of tumors in each zone was counted. Twelve out of 30 tumors were located entirely within the most lateral zone. An additional 14 tumors occurred in both the most lateral and the interjacent zones. Thus, almost 90% of the observed tumors were localized in more lateral zones of the pars distalis (Chi-squared test, p less than 0.01). These findings support a hypothesis that lower portal blood dopamine levels reaching lateral portions of the pars distalis are a factor in the higher incidence of lactotroph adenomas in these zones.
D000236:Adenoma / Q000378:metabolism / Q000473:pathology; D000375:Aging / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism; D005260:Female; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000378:metabolism*
D011388:Prolactin; D004298:Dopamine