Identification and purification of a human Sertoli cell-secreted protein (hSCSP-80) stimulating Leydig cell steroid biosynthesis.
Human Sertoli cells in vitro secrete a factor that stimulates steroid biosynthesis in purified human and rat Leydig cells as well as in the MA-10 mouse tumor Leydig cell line. MA-10 cells were used as a bioassay system to follow the characterization and purification of the active principle in the conditioned medium of human Sertoli cells. The Leydig cell stimulatory factor is a thermo-labile and trypsin-sensitive protein retained onto 10,000 mol wt (MW) cut-off filters. The following scheme was used to purify the active protein: concentration by ammonium sulfate (80%) precipitation, followed by dialysis using molecularporous membrane tubing of MW cut-off 12,000-14,000, heparin-agarose, Concanavalin-A-Sepharose, and immobilized reactive textile dye affinity chromatography. Yellow 86 and green 19 dyes immobilized on agarose matrix were used. This procedure resulted in the rapid (less than 24-h) purification of a 79,000 +/- 6,082 (n = 3; under denaturating conditions) MW protein which stimulated Leydig cell steroid biosynthesis 25-fold at picomolar concentrations. The MW of the biologically active protein was further confirmed to be around 80,000 by gel filtration chromatography. This 80,000 MW human Sertoli cell-secreted protein (hSCSP-80) was shown to be different from human transferrin, human serum albumin, and rat testibumin. hSCSP-80, by modulating Leydig cell steroid biosynthesis, may play a significant role in the regulation of testicular function.
Papadopoulos
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Department of Anatomy and Cell Biology, Georgetown University School of Medicine, Washington, D.C. 20007.
D000368:Aged; D002478:Cells, Cultured; D003470:Culture Media; D006801:Humans; D007985:Leydig Cells / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D009994:Osmolar Concentration; D011506:Proteins / Q000302:isolation & purification* / Q000378:metabolism / Q000502:physiology; D012708:Sertoli Cells / Q000378:metabolism*; D013256:Steroids / Q000096:biosynthesis*; D013268:Stimulation, Chemical
D003470:Culture Media; D011506:Proteins; D013256:Steroids