Biology Reference
In-Depth Information
Fig. 13.5
Schematic diagram
demonstrating
Kiss1
upregulation during the
GnRH/LH surge in female
rodents and sheep. In rodents,
Kiss1
mRNA (
red dots
)
increases in the anteroventral
periventricular nucleus
(AVPV) at the time of the
preovulatory GnRH/LH surge
(Proestrus PM). In the arcuate
nucleus (ARC),
Kiss1
mRNA
is reduced at this time. In
sheep,
Kiss1
mRNA is
stimulated in the caudal ARC
and preoptic area (POA)
immediately prior to the
GnRH/LH surge (late
follicular)
A Case for the ARC and POA in Ovine Species
In sheep, kisspeptin administration is able to synchronize preovulatory LH surges in
ovary-intact cycling ewes and also stimulate the surge in seasonally acyclic ewes
[
75
,
76
]. Conversely, kisspeptin antagonist administration is able to inhibit the
estradiol-induced LH surge [
15
]. In this species, there are three types of estrogen
feedback important for the control of GnRH secretion: short-term negative feed-
back, long-term negative feedback, and acute positive feedback [
77
]. As is the case
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