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Surface‐associated glycosyltransferase activities in rat sertoli cells in vitro
Author(s) -
Raychoudhury Samir S.,
Millette Clarke F.
Publication year - 1993
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080360210
Subject(s) - biology , fucosyltransferase , sertoli cell , hormone , spermatogenesis , transferrin , biochemistry , testosterone (patch) , microbiology and biotechnology , medicine , endocrinology , enzyme
We have previously demonstrated fucosyltransferase (FT) activity on mouse germ cell surfaces at different stages of spermatogenesis. To complement these findings, here we report FT activity on the Sertoli cell (SC) surface. SC isolated and cultured from 20‐day‐old rat testes displayed FT activity with a V max of 12.5 pmoles/mg protein/min and a K m of 22 μM, while purified Sertoli cell plasma membranes (SCPM) showed FT activity with a V max of 10 pmoles/mg protein/min and a K m of 18.2 μM for GDP‐[ 14 C]‐L‐fucose. Fucosyltransferase activities were 16.7 and 2.6 pmoles/mg protein/min in SC and SCPM, respectively; 16% of FT activity is, therefore, on the cell surface. To test whether the expression of FT activity in SC was regulated by hormones and growth factors, SC were cultured in serum‐free medium supplemented with insulin, transferrin, sodium selenite, and epidermal growth factor (medium 4F) or in 4F plus follicle‐stimulating hormone, testosterone, hydrocortisone, and vitamin E (medium 8F). We found that FT activity in SC is not modulated by these hormones or growth factors (4F or 8F). For comparison with FT, galactosyltransferase (GalTase) activities in SC and SCPM were also determined. SC displayed GalTase activity with a V max of 50 pmoles/mg protein/min and a K m of 38.5 μM, while SCPM showed GalTase activity with a V max of 25 pmoles/mg protein/min and a K m of 20.8 μM for UDP‐[ 3 H]‐galactose. Galactosyltransferase activities were 29.2 and 9.6 pmoles/mg protein/min in SC and SCPM, respectively. Therefore, ∼33% of the total cell GalTase activity was detected on the surface membranes of rat Sertoli cells. These results suggest that cell surface glycosyltransferases may be involved in Sertoli cell function during mammalian spermatogenesis. © 1993 Wiley‐Liss, Inc.