Effect of wortmannin. Cultures were treated with
dimethyl sulfoxide vehicle (□) or 100 nM wortmannin
(░⃞) at 37°C for 0.5 hr, followed by treatment with insulin
or IGF-I for 1.5 hr. Then, cells were briefly trypsinized, and recovery
of surface GH binding was measured 2 hr after trypsinization. Vs.
dimethyl sulfoxide control, ∗, P < 0.05 and ‡,
P < 0.01. vs. dimethyl sulfoxide insulin; †,
P < 0.05. vs. wortmannin control; ¶,
P = 0.01.