Unraveling the Neural Mechanisms Underlying the GnRH Pulse Generator: An Update

Abstract The discovery of episodic LH secretion in 1970 initiated considerable effort by reproductive neuroendocrinologists to understand the neural mechanisms underlying the synchronous release of GnRH that drives pulsatile LH secretion. Our previous chapter reviewed the history of these efforts and considered a new model for the GnRH pulse generator based on KNDy neurons in the arcuate nucleus that contain k isspeptin, n eurokinin B, and d ynorphin. In this update of that chapter, we retain the original historical material and discuss recent experimental tests of the roles of these peptides. Based on these studies, we propose a modified model for the GnRH pulse generator in ruminants and rodents, the core of which is comprised of KNDy neurons, and discuss whether this model is applicable to humans and other primates.