Characterization of somatotropin- and prolactin-binding sites on bovine granulosa cells using homologous hormones.
Specific binding of bovine somatotropin (BST) and bovine prolactin (BPRL) to cow granulosa cells from antrum-containing follicles of different diameter was studied. Scatchard analysis of the data revealed a single type of low affinity BST-binding sites on the granulosa cells with dissociation constants similar to those for the BPRL-binding sites. The number of BST-binding sites on the cells decreased with increasing follicle diameter from 3-5 to 6-10 mm. However, the binding capacity to BPRL decreased only in the case of cells from follicles 11-20 mm in diameter. The findings are discussed in relation to the "homologous binding" phenomenon.
Lebedeva
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IY
All-Union Research Institute of Farm Animal Genetics and Breeding, Russian Academy of Agricultural Sciences, Moskovskoe Shosse 55a, Pushkin, St. Petersburg, 189620 Russia.
Lebedev
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VA
Kuzmina
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TI
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002417:Cattle; D048429:Cell Size; D002478:Cells, Cultured; D005260:Female; D006107:Granulosa Cells / Q000166:cytology / Q000378:metabolism*; D013006:Growth Hormone / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*
D011388:Prolactin; D013006:Growth Hormone