Induction of nucleolar changes in rat luminal cells by single injection or low-dose infusion of estradiol.
The nucleolar area of rat uterine luminal epithelial cells was measured for 41 h after beginning either of two dosage regimens of estradiol (E2): a single injection of 1.0 microgram E2 or a continuous infusion of E2 at a rate of 1.0 microgram/24 h. In response to a single injection of E2, mean nucleolar area was significantly elevated above control levels by 10 h. Nucleolar morphology showed slight changes, but the fibrillar component was always associated with 2-3 fibrillar centers by 10 h. In response to a continuous infusion of E2, mean nucleolar area was elevated by 10 h, reached a maximum by 18 h, and remained relatively constant thereafter. Nucleolar morphology showed significant changes by 10 h; the fibrillar component was commercially denser. Bivariate histograms of nuclear versus nucleolar areas showed a bimodal distribution after both injection and infusion, suggesting that two size classes of nuclei existed after estrogen stimulation. The results suggest that: 1) a continuous infusion of E2 at a rate of 1.0 microgram/24 h was more effective in inducing larger increases in nucleolar area and transcription than a single injection of 1.0 microgram E2 at time 0; 2) using analysis of nuclear and nucleolar areas two subpopulations of cells were identified; and 3) continuous infusion of E2 produced a steady state of ribosome production and cytoplasmic transport by 18 h.
Roberts
D K
DK
Department of Obstetrics and Gynecology, Wesley Medical Center, University of Kansas School of Medicine-Wichita 67214.
Lavia
L A
LA
Walker
N
N
Anderson
K
K
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004848:Epithelium / Q000378:metabolism / Q000648:ultrastructure; D004958:Estradiol / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D006651:Histocytochemistry; D007262:Infusions, Intravenous; D051381:Rats; D011919:Rats, Inbred Strains; D014158:Transcription, Genetic; D014599:Uterus / Q000378:metabolism* / Q000648:ultrastructure
D004958:Estradiol; D004247:DNA