Fig. 8.

Effect of overexpressed CIRL on ATP-dependent and ATP-independent secretion. Chromaffin cells were transfected with plasmids for hGH (pXGH5) and either pCDR7 or pCMVneo, as in Figure 2. After 4 d the cells were permeabilized with 20 μm digitonin in KGEP buffer without Ca²⁺ and with or without 2 mm MgATP for 4 min, followed by incubation with or without 30 μmCa²⁺ in the continuing presence or absence of 2 mm MgATP for 2 min (A, B) or for 2 and 15 min (C, a separate experiment). The amounts of hGH (A, C) and catecholamine (B) released into the medium and the amounts remaining in the cells were determined as described;n = 4 wells/group.