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.
Stojilkovic
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Stanko S. Stojilkovic and Melanija Tomić are at the Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Tomić
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