title: Production of mitogenic factor(s) by ovine corpora lutea throughout the estrous cycle.
abstract: To evaluate secretion of mitogenic factors by ovine corpora lutea (CL) at several stages of development, luteal explants from days 5 (n = 12 ewes), 10 (n = 6 ewes), and 15 (n = 6 ewes) of the estrous cycle were incubated in serum-free medium for 24 h. Luteal-conditioned media (LCM) were evaluated for their ability to stimulate proliferation of endothelial, BALB/3T3, and ovarian granulosa cells. After mitogenic activity of LCM from individual animals was evaluated, pools of LCM from each day of the estrous cycle were subjected to anion-exchange, cation-exchange, and heparin-affinity chromatography to characterize mitogenic activity. Pools of LCM also were utilized for ultrafiltration, heat-treatment, trypsin-treatment, and immunoneutralization studies. Results demonstrated that ovine CL secrete mitogenic activity that stimulates (P less than 0.01) proliferation of endothelial (135.7 +/- 5.3% of control) and granulosa cells (188.9 +/- 2.9%) but not 3T3 (103.2 +/- 2.5%) cells. Differences between stages of luteal development were not observed. The mitogenic activity bound to diethylaminoethyl-Sephacel and heparin-agarose, but not to carboxymethyl-Sepharose, indicating that ovine luteal mitogenic factor(s) is anionic and may belong to the heparin-binding growth factor (HBGF) family. In addition, the mitogenic activity was heat-labile, trypsin-sensitive, and appeared to have a M(r) greater than 100,000. Mitogenic activity for endothelial cells was partially neutralized with a specific antibody against HBGF-1 and was completely abolished with a specific antibody against HBGF-2. Moreover, HBGF-1 and HBGF-2 were immunolocalized in histological sections of CL from days 5 (n = 5 ewes), 10 (n = 5 ewes), and 15 (n = 5 ewes) after estrus. These findings are the first report of a major mitogenic factor(s) produced by cyclic ovine CL and indicate this factor is an HBGF-2-like molecule.
authors.affiliation: Department of Animal and Range Sciences, North Dakota State University, Fargo 58105.
authors.forename: A T
authors.initials: AT
authors.lastname: Grazul-Bilska
authors.forename: D A
authors.initials: DA
authors.lastname: Redmer
authors.forename: S D
authors.initials: SD
authors.lastname: Killilea
authors.forename: K C
authors.initials: KC
authors.lastname: Kraft
authors.forename: L P
authors.initials: LP
authors.lastname: Reynolds
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D003338:Corpus Luteum / Q000502:physiology*; D016895:Culture Media, Serum-Free; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D004971:Estrus / Q000502:physiology*; D005260:Female; D016220:Fibroblast Growth Factor 1 / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008934:Mitogens / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D009924:Organ Culture Techniques; D012756:Sheep
chemical_list: D016895:Culture Media, Serum-Free; D008934:Mitogens; D016222:Fibroblast Growth Factor 2; D016220:Fibroblast Growth Factor 1