[45Ca flow from cultured pituitary cells: effect of TRH and potassium]

Potassium (KCl: 50 mM) increases the uptake of 45Ca by GH3/B6 pituitary cells whereas TRH (100 nM) does not modify the uptake. On the contrary, 45Ca efflux is quickly and transiently increased by TRH whereas KCl has no influence on the 45Ca outflow. Our results suggest that these two secretagogues act on the GH3 pituitary cells by different processes.