Fig. 7.
Growth hormone secretagogues and growth hormone-releasing peptides do not affect the dissociation of 125I-ghrelin; as in Fig. 6B, the loss of specific binding at 4°C of 125I-ghrelin to membranes of HEK293 cells coexpressing Gαo1 and the ghrelin receptor was assessed over time as a measure of the dissociation rate. A, as well as addition of 10−6 M ghrelin at time 0, L-692,585 (3 × 10−7 M) was also present. Koff = 0.01 ± 0.00 min−1. Data points represent mean ± S.E.M of three independent experiments performed in triplicate. B, varying concentrations of GHRP-6 (top), L-692,585 (middle), or MK-677 (bottom) were added along with 10−6 M ghrelin. The level of specific binding of 125I-ghrelin was then measured at time 0 and at 60 min. Data points represent mean ± S.E.M of three independent experiments performed in triplicate; data are shown as semi-log plots and analyzed using linear regression.