In vitro effects of ethanol on gonadotropin-binding sites in porcine granulosa cells.

In this study, we examined the in vitro effects of ethanol on [125I]human follicle-stimulating hormone (hFSH) and [125I]human luteinizing hormone (hLH) binding to porcine granulosa cells (GCs). The GC suspensions and [125I]hFSH or [125I]hLH were incubated in the presence or absence of 1-50% (vol/vol) ethanol until steady state binding was attained for 2 h at 37 degrees C. The presence of 1-4% ethanol significantly enhanced the specific binding of hFSH to porcine GCs, with a maximal effect at 4% ethanol, however, had no effect on hLH binding. Higher concentration of ethanol (8-50%) significantly decreased both specific hFSH and hLH binding to porcine GCs. Scatchard analyses revealed that ethanol increased the number of FSH-binding sites without changing the affinity for FSH. The data suggest that porcine GCs contain a population of masked FSH-binding sites exposed by in vitro treatment with ethanol. Furthermore, the membrane fluidity may play an important role in the masking/unmasking mechanism of FSH-binding sites within the porcine GCs.