Figure 2.
Coupling of the GnRH-R to adenylyl cyclase and regulatory G proteins in GT1-7 cells. (A and B) GnRH-induced biphasic changes in cAMP production (open circles) with stimulation at low agonist concentrations and progressive inhibition at higher concentrations in cultured hypothalamic cells (A) and GT1-7 neurons (B). In the presence of PTX (filled circles), the inhibition of cAMP production by high GnRH concentrations is diminished. (C and D) Dose- and time-dependent effects of GnRH on membrane-associated αi3 immunoreactivity. (E) PTX and CTX on membrane-associated αi3 immunoreactivity. (F) Effects of a GnRH antagonist (d-pGlu) on membrane-associated αq/11. (G and H) Effects of PTX alone (G) or with a GnRH agonist (d-Ala6) (H) on episodic GnRH release. Basal/washing indicates the GnRH profile during perifusion with medium alone and/or washout of the treatment. Asterisks indicate significant differences (P < 0.05) compared with the control.