Multiple intracellular signallings involved in regulation of ion channels by GH releasing or inhibitory hormones in pituitary somatotropes

摘要

Influx of Ca~2+ via Ca~2+ channels is the major step triggering exocytosis of pituitary somatotropes to release growth hormone (GH). Voltage-gated Ca~2+ and K~+ channels, the primary determinants of the influx of Ca~2+ in somatotropes, are regulated by GH-releasing hormone (CHRH) and somatostatin (SRIF) through G protein-coupled sig- nalling systems. Using whole-cell patch-clamp techniques, the changes of the Ca~2+ and K~+ currents in primary cultured somatotropes were recorded and signalling systems were studied using pharmacological reagents and intracellular dialysis of non-permeable molecules including antibodies and antisense oligonucleotides.