In vitro Effects of Ethanol on Gonadotropin-Binding Sites in Porcine Granulosa Cells

Summary

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 2h at 37 ^°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.

Key words

Ethanol - Gonadotropin - Masked receptor - Porcine - Granulosa cells