ISSN:
0003-276X
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Proliferation of the mammary gland epithelium on days 2, 3, 4, 6, 8, 12, 16, and 19 pregnancy has been studied in mice, by means of radioautography. Each animal received an intraperitoneal injection of 25°c of tritiated thymidine and was killed one hour later. The inguinal mammary glands were processed for paraffin sectioning and radioautographs prepared using the dipping technique. The rate of mammary epithelial cell proliferation was quantitated for each animal by determining the percent of labeled epithelial cells in a large sample (〉 2000 cells) of cells (labeling index).The data showed that the proliferative activity of the mammary epithelium during pregnancy followed a bimodal distribution. The first evidence of a proliferative response to pregnancy was noted on day 3. By day 4, the labeling index reached a maximum of 25.3%. The labeling index declined on days 6 and 8 to 7.5% and 8.0% respectively. On day 12, the labeling index increased to 12.1%, then fell to 7.9% and 1.3% on day 16 and 19, respectively.Separate labeling indexes were determined for the interlobular epithelium (ducts) on day 12, 16, and 19. The data showed that the labeling indexes of the interlobular and intralobular epithelium during these stages of pregnancy were not significantly different. The correlation of the hormones secreted during pregnancy with the data on mammary epithelial proliferation is discussed.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/ar.1091590213
