Figure 6.

LH secretion. A, Effect of SK or BK channel blockade on GnRH-stimulated LH secretion. After 3 d culture without (upper graph) or with (lower graph) 0.2 nm E₂, LH secretion from mouse anterior cells was monitored in response to 15-min pulses of 1 nm GnRH. For the toxin-treated groups, either 100 nm apamin or 100 nm iberiotoxin was included in the medium beginning at 15 min before the first GnRH pulse and continuing a total of 45 min. Results are expressed as mean ± sem from three to six independent experiments per treatment group. Where not shown, the error bar is smaller than the symbol representing the mean. B, Effect of E₂ (0.2 nm, 3 d) on LH secretion in response to three 15-min pulses of 1 nm GnRH with 1-h interpulse intervals. Secretion rates for pulses 1 and 2 are shown in A [no-toxin ctrl (control)]. Mean ± sem from six independent experiments per treatment group. *, Significantly different from no steroid (P < 0.001).