OMEGA-CONOTOXIN-SENSITIVE CA2-GATED CHANNELS MODULATE PROTEIN SECRETION IN CULTURED RAT SERTOLI CELLS( VOLTAGE)

Recent results have demonstrated that substantial calcium influx in ra t Sertoli cells is mediated by cation channels of both Land N-type. In this report we have investigated the possible role of such channels i n the protein secretion of immature rat Sertoli cell monolayers. The b locking of N-type voltage-gated channels by omega-conotoxin (omega-CTX ) GVIA results in a 50-60% inhibition of the protein secretion in the culture medium while total protein and RNA synthesis are not affected. The same extent of protein secretion inhibition is obtained in FSH-st imulated Sertoli cells. L-type voltage-gated channels apparently are n ot involved in such a modulation. These data, showing that a major fra ction of secreted proteins from cultured rat Sertoli cells is Ca2+ dep endent, represent the first evidence of a physiological role of voltag e-operated Ca2+ channels in mammalian testis. (C) 1997 Elsevier Scienc e Ireland Ltd.