Fig. 4.

Signal dependence of agonist effects on cell surface GnRHR expression. HeLa cells transduced with HA-hGnRHR or HA-h.XGnRHR with or without the A261K mutation (1 pfu/nl) were incubated for 18 h with 10⁻⁷ M IN3 (●) or with no addition (○) before being washed and incubated for the indicated periods with 10⁻⁷ M Buserelin at 37°C. These incubations were terminated by washing at 4°C, before staining for cell surface HA-tagged GnRHRs. Data shown are the surface expression index (arbitrary units) determined as above and are means ± SE (n = 3) from 3 separate experiments (each with 3 replicate wells per treatment) and are normalized to the internal control value. **P < 0.01 compared with CTRL.