ESPE Yearbook of Paediatric Endocrinology

To read the full abstract: Endocrinology 2019;160:557–567.

There is now no doubt that arcuate nucleus (ARC) kisspeptin neurons are the GnRH pulse generator. The authors analyzed the activity of ARC kisspeptin neurons by using a very powerful method based on the recording of calcium concentration within cells.

ARC kisspeptin neurons activity was analyzed in male mice over a period of 24 hours. Synchronous activation of ARC kisspeptin neurons was defined as a synchronization episode (SE), and each SE was associated with a LH pulse. SE’s occurred on average every 166 minutes (range: 43 to 347 minutes). The inter-SE interval showed no difference between day and night, but decreased to on average 16 minutes in gonadectomized (GDX) mice, with the same 1:1 link between SEs and LH pulses as in intact mice. The wide range of inter-SE intervals and the perfect correlation between SE and LH pulses throughout the 24 hours period in both intact and GDX mice indicate that the GnRH pulse generator operates in a stochastic manner.

This analysis in male mice improves our understanding of the activity of the GnRH pulse generator. Additional studies are needed to understand the mechanism that synchronizes the activity of ARC kisspeptin neurons altogether, and also how this frequency is accelerated in GDX mice.