Bromocriptine enhances endogenous caveolin-1 mRNA expression in GH3 cells. (A) Panel a: Expression of caveolin-1 mRNA was enhanced after bromocriptine treatment. Panel b and c: Cellular proteins were extracted and Western blots performed 48 hours after recombinant caveolin-1 was transfected into GH3 cells (lane 2 and 5). Vehicle transfections (lane 1 and 4) were used as controls. Panel b is an immunoblot using rabbit anti-caveolin-1 antibody and panel c is an immunoblot using monoclonal anti-Myc antibody against Myc-tagged caveolin-1. Arrowhead indicates Myc-tagged caveolin-1. Arrow indicates endogenous caveolin-1. Protein extracted from A431 cells was used as an immunoblotting positive control. (B) Recombinant caveolin-1 expressed in A431 cells has identical perinuclear localization with endogenous caveolin-1. Myc-tagged caveolin-1 was transfected into A431 cells (a, c) for 48 hours. Non-transfected A431 cells were used to examine endogenous caveolin-1 localization (b, d). Cells were fixed and immunocytochemically stained with anti-caveolin-1 antibody then visualized by anti-rabbit IgG conjugated-FITC secondary antibody to detect exogenous (a) and endogenous (b) caveolin-1. Monoclonal anti-Myc antibody combined with anti-mouse IgG conjugated-Texas-Red was used to recognize recombinant caveolin-1 (c). Filamentary actin was stained with phalloidin conjugated-Texas-Red to observe cell morphology (d). Scale bar = 20 μm.