Inositol phosphate production in COS-1 cells transiently transfected with the GfA (A) and GfB (B) GnRH receptor subtypes, after stimulation for 1 h with various GnRH agonists. ▾, mammalian GnRH; ▴, [Trp7,Leu8]GnRH (sGnRH); ■], [His5,Trp7,Tyr8]GnRH (cGnRH II); and ♦, [Ser8]GnRH (sea bream GnRH). For both receptor subtypes, cGnRH-II has the highest potency, followed by sGnRH, mammalian GnRH, and sea bream GnRH.