The secretion of transforming growth factor-beta by bovine luteal cells in vitro.
Transforming growth factor-beta (TGF-beta), a multifunctional polypeptide growth factor, is produced by follicular cells in the ovary. However, there is little information indicating that TGF-beta is produced in the post-ovulatory follicle, i.e. the corpus luteum. In the present communication we present evidence that bovine luteal cells secrete large amounts of TGF-beta when maintained in moderate-term monolayer culture. Using TGF-beta 1 and TGF-beta 2 subtype-specific antibodies to neutralize the bioactivity it was found that 80-90% TGF-beta activity in luteal cell conditioned medium (LCCM) is due to TGF-beta 1, whereas < or = 10% TGF-beta activity in LCCM is due to TGF-beta 2. TGF-beta subtype nonspecific antibodies effectively and completely neutralized all TGF-beta activity in LCCM. The ratio of TGF-beta 1:TGF-beta 2 as estimated on the basis of neutralization studies was supported by visual observation of TGF-beta 1 and TGF-beta 2 protein bands on Western blotting. Using a modified and rapid mink lung epithelial cell bioassay and authentic TGF-beta to generate standard curves, the amount of TGF-beta secreted by luteal cells in vitro was quantitated. The concentration of luteal cell secreted proteins in the medium increased with time during 7 days of culture. Likewise, the TGF-beta concentration in LCCM increased during 7 days. To study the effect of duration of culture on the rate of TGF-beta secretion by luteal cells, conditioned medium was collected at 24 h intervals and replaced with fresh nutrient medium.(ABSTRACT TRUNCATED AT 250 WORDS)
Gangrade
B K
BK
Department of Obstetrics and Gynecology, University of Kansas School of Medicine, Wichita.
Gotcher
E D
ED
Davis
J S
JS
May
J V
JV
D000818:Animals; D001681:Biological Assay; D002417:Cattle; D002478:Cells, Cultured; D016922:Cellular Senescence; D003338:Corpus Luteum / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000737:chemistry; D004848:Epithelium; D005260:Female; D008168:Lung; D008907:Mink; D011247:Pregnancy; D012636:Secretory Rate; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D017077:Culture Media, Conditioned; D016212:Transforming Growth Factor beta