GnRH-induced calcium and current oscillations in gonadotrophs.

The rat pituitary gonadotroph is a well-studied cell model for investigation of the oscillatory nature of calcium signaling in agonist-stimulated excitable cells. Cytosolic calcium levels ([Ca(2+)](i)) in gonadotrophs are controlled by two distinct oscillators, a plasma membrane oscillator that generates extracellular calcium-dependent low-amplitude [Ca(2+)](i) spiking in unstimulated cells and an endoplasmic reticulum oscillator that is activated by calcium-mobilizing receptors for GnRH, endothelin, and pituitary adenylate cyclase-activating polypeptide. In this review, the characteristics of the spontaneous and agonist-induced calcium oscillations in gonadotrophs and the coordinate actions of the two oscillators during GnRH action discussed.