2026-09-17T06:18:41Zhttps://gredos.usal.es/oai/request

oai:gredos.usal.es:10366/1580962025-04-30T19:23:14Zcom_10366_3948com_10366_3947com_10366_3946com_10366_3823col_10366_3949

Variations in the cellular proliferation of prolactin cells from late pregnancy to lactation in rats Carretero González, José Rubio, Manuel Blanco, Enrique Burks, Deborah J. Torres, José L. Hernández, Elena Bodego, Pilar Riesco-López, José M. Juanes Méndez, Juan Antonio Vázquez, Ricardo Prolactin cells Cellular proliferation Late pregnancy Lactation [EN]Lactation is a physiological process associated with hyperactivity of hypophyseal prolactin-producing cells. It is known that the percentage of these cells is increased during lactation, although there are discrepancies in the reports regarding the mechanisms responsible for increasing the number of prolactin cells. In order to analyse whether this increase is a result of previous proliferation, variations in the proliferation rate of prolactinpositive cells were determined from late pregnancy to lactation in adult female rats by means of observation of the immunohistochemical expression of PCNA as a marker of cellular proliferation. During late pregnancy, a very significant increase in the percentage of proliferating prolactin cells was observed in comparison to non-pregnant females in the proestrus phase (p < 0.01). Although the percentage of prolactin-positive cells after one week of lactation was higher than in non-lactating or in pregnant females (p < 0.01), the proliferation rate was lower than in the other groups studied. In sum, our results suggest that late pregnancy constitutes a preliminary proliferative phase preparatory to the ensuing lactation phase and that endocrine changes in late pregnancy involve the cellular proliferation of hypophyseal prolactin cells in order to prepare the gland for later demands and to prevent proliferative changes from occurring during lactation. 2024-05-29T07:47:19Z 2024-05-29T07:47:19Z 2003 info:eu-repo/semantics/article 0940-9602 http://hdl.handle.net/10366/158096 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess Attribution-NonCommercial-NoDerivatives 4.0 Internacional