Somatostatin inhibits two types of voltage-activated calcium currents in rat growth-hormone secreting cells.
Somatostatin is known as the hypothalamic inhibitor of growth-hormone (GH) secretion from the pituitary gland. The present study examines the effects of somatostatin on voltage-gated calcium currents recorded from enriched populations of normal GH-secreting cells (somatotrophs). Two types of voltage-activated calcium currents were recorded from somatotrophs with the whole-cell mode of the patch-clamp technique. Somatostatin exerted a reversible blocking effect on these two types of calcium currents. These findings suggest that somatostatin can regulate intracellular calcium in somatotrophs by a direct control of calcium fluxes across the plasma membrane of these cells, thereby affecting the level of GH secretion.
Nussinovitch
I
I
Department of Anatomy, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D013006:Growth Hormone / Q000378:metabolism*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D013004:Somatostatin / Q000494:pharmacology*
D015220:Calcium Channels; D013004:Somatostatin; D013006:Growth Hormone; D002118:Calcium