Mitogenic actions of endothelin and other growth factors in ovine endometrium.
Endothelin-1 (ET-1) is present in ovine endometrium, primarily in epithelial cells, and increases around the time of implantation. We examined the cell type expressing ET-binding sites in vitro and whether ET-1 has mitogenic actions in the endometrium, alone or in synergy with other growth factors. Purified epithelial and stromal cells were prepared from luteal-phase endometrium. Specific receptors were demonstrated by binding of 125I-ET-1 and proliferative effects of ET-1 and/or other growth factors determined by uptake of [3H]thymidine by cells in serum-free culture. 125I-ET-1 bound to both epithelial (2516 +/- 820 c.p.m./well) and stromal (6368 +/- 1350 c.p.m./well) cells and was displaced by ET-1 (1 mumol l-1). There were no proliferative effects of ET on epithelial cells. ET-1 (10 nmol l-1) stimulated uptake of [3H]thymidine by stromal cells under serum-free conditions in 13/20 individual cell preparations, to 149 +/- 13% of control (untreated = 100%) with dose-dependence between the range of 1 to 100 nmol l-1. Stimulation by fetal calf serum was to 377 +/- 126% of control. The effects on proliferation by other growth factors (dose; % of control +/- S.E.M., number of positive/total number of cell preparations) were: IGF-I (13 nmol l-1; 182 +/- 14, 4/4), epidermal growth factor (EGF; 4.8 nmol l-1; 132 +/- 5%, 7/7), platelet-derived growth factor-BB (0.4 nmol l-1; 146 +/- 3, 2/2) and leukaemia inhibitory factor (0.4 nmol 1-1; 110 +/- 2, 3/3). All stimulations except that of EGF were significant and dose-responsive but only insulin was additive with ET (350 +/- 35, 5/5). ET-1 also stimulated expression of the the AP-1 cis element c-jun, this being maximal at 60 min of exposure to mitogen. ET-1, along with other growth factors has a likely paracrine role in cellular proliferation in the endometrium, possibly in association with blastocyst implantation.
Salamonsen
L A
LA
Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia.
Young
R J
RJ
Garcia
S
S
Findlay
J K
JK
D000818:Animals; D000077214:Becaplermin; D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004717:Endometrium / Q000187:drug effects* / Q000502:physiology; D019332:Endothelin-1 / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D016758:Genes, jun; D006131:Growth Inhibitors / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008183:Luteal Phase; D008222:Lymphokines / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011485:Protein Binding; D020574:Proto-Oncogene Proteins c-sis; D012756:Sheep; D013268:Stimulation, Chemical
D019332:Endothelin-1; D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D008222:Lymphokines; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I