title: Effects of tumors on the daily mitotic activity of mouse pars intermedia.
abstract: We have investigated the effects of EA21a and EA34 mammary carcinomas on daily PI cell proliferation in mice. Animals were divided into groups grafted with either EA34 or EA21a carcinomas (and a non-grafted control group). They were all injected intraperitoneally with 2 microg colchicine per g of body weight 4 h before sacrifice and the number of mitoses per 1000 nuclei was calculated. The mitotic index (MI) of pars-intermedia epithelial cells in control animals showed significant temporal variations. However, the MI from mice grafted with EA34 or EA21a carcinomas showed no such variation. There was no difference between the daily MIs of controls and tumor grafted groups. The absence of a 24 h mitotic activity curve in both EA21a and EA34 tumor-bearing animals demonstrates a lower level of synchronization of cells entering mitosis.
authors.affiliation: Institute of Biology, Embryology and Histology, School of Medicine, National University of La Plata (Unlp) 1900, La Plata, Buenos Aires, Argentina.
authors.forename: Jose Miguel
authors.initials: JM
authors.lastname: Surur
authors.forename: Vicente Alberto
authors.initials: VA
authors.lastname: Catalano
authors.forename: Mirta Alicia
authors.initials: MA
authors.lastname: Flamini
authors.forename: Claudio Gustavo
authors.initials: CG
authors.lastname: Barbeito
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000473:pathology*; D049109:Cell Proliferation; D005260:Female; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D051379:Mice; D008809:Mice, Inbred C3H; D008938:Mitosis; D010902:Pituitary Gland / Q000166:cytology*