Proliferative Activity of Pituitary Mammotrophs in Culture : a Morphological Study on DNA Synthesis Using In Vitro Bromodeoxyuridine Labeling Method

Abstract

The present study was designed to investigate the proliferative activity of mammotroph in the long-term monolayer cultures of male rat pituitaries by use of bromodeoxyuridineflsrdl.ll-labeltnq technique combined with double immunohistochemical staining. Rat anterior pituitary cells were exposed to 100 uM BrdU for 4 hrs at 4, 7, 12, 15, 20, 25 and 30 days in the primary cultures. After fixation with modified Camoy's fixative, double immunohistochemical staining with anti-BrdU and antiprolactin antibody was performed. It was shown that the ratio of BrdU-Iabeled mammotrophs per 100 mammotrophs(BrdU Labeling Index) was 8.2% at 4 day and 8. 0% at 7 day in our cultures. Thereafter, it decreased until 30 days(1.7%). These results demonstrated that the increase in the proportion of mammotrophs observed in our previous monolayer cultures is caused, at least in part, by the cell division of mammortrophs.