Fig. 3.

Secretion stimulated by α-latrotoxin requires extracellular Ca²⁺. Chromaffin cells were transfected with plasmids for hGH (pXGH5) and either pCDR7 or pCMVneo, as in Figure 2. After 4 d the cells were incubated for 10 min with or without 26 pm α-Ltx in either PSS without Ca²⁺ or Mg²⁺ and with 0.2 mm EGTA (indicated as −Ca), or PSS containing 2.2 mm Ca²⁺ and 0.5 mmMg²⁺ (indicated as +Ca). The amounts of hGH (A) and catecholamine (B) released into the medium and the amounts remaining in the cells were determined as described; n = 4 wells/group.