To read the full abstract: Endocrinology 2019;160:14801491.
There is now no doubt that arcuate nucleus (ARC) kisspeptin neurons are the GnRH pulse generator. (With paper 1.8) this second paper describes the activity of the GnRH pulse generator across the estrous cycle. In this work, the variable level of E2 represented an additional complexity. The second interest was to understand how the GnRH pulse generator could be involved in the LH surge.
The results show that the GnRH pulse generator operates at a constant rate across the estrous cycle. In addition, the GnRH-pulse frequency remains unchanged during the LH surge, which indicates that additional mechanisms provoke the large LH release at the transition between the proestrus and the estrus. Paper 1.7 shows that E2 regulates LH surge generation through AVPV (rather than ARC) kisspeptin neurons. The current model confirms that the LH surge is independent from the ARC kisspeptin neuron pathway. Finally, this work confirmed the major inhibitory role of progesterone on GnRH pulse generator activity in female mice.