Figure 7.

Different types of Ca²⁺ and CaM oscillations induced by CCK in various regions of a pancreatic acinar cell; schematic diagram indicating the hormone-evoked movements of CaM induced by global [Ca²⁺]_i spikes. Application of CCK evokes initially a very long [Ca²⁺]_i transient and, thereafter, repetitive, regular global Ca²⁺ spikes (34). The first movement of CaM (1) is into the secretory granule region. CaM leaves this region as soon as [Ca²⁺]_i falls (2). There is a delayed but substantial movement of CaM into the nucleus (3). The exit of CaM from the nucleus (4) is very slow, allowing integration of the pulses of CaM influx to give a sustained rise in the nuclear CaM concentration.