Electrophysiology of human growth hormone secreting tumour cells and its modification by hGRF has been studied using on-cell and Nystatin-perforated whole-cell recording configurations. Local application of hGRF (10 nM) produced an increase in the frequency of action potentials. Ca2+ currents were isolated by a ramp depolarizing pulse from -120 mV to +60 mV in the presence of tetrodotoxin (1 μM). Human GRF increased the Ca2+ currents which could be blocked by Ni+ (300 μM). We conclude that an increase in Ca2+ current is integral to the action of hGRF on these cells.
- Ca current
- Growth hormone