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Fig. 19.1
Activation of ARC kisspeptin cells by a surge-inducing stimulus, and reduction in activity
in the same cell group with chronic estrogen treatment. Ovariectomized ewes received 50
μ
g
estradiol-17
β
as a single i.v. injection (acute treatment) 1 h before brain collection, or estradiol-17
β
implants for 2 weeks (chronic treatment). Panels (
a
-
d
) show kisspeptin (
brown
) and Fos (
black
)
labeling by immunohistochemistry (
scale bars
50
m). (
a
) Is a low power image, showing the loca-
tion of the kisspeptin cells in the ARC, (
b
-
d
) show Fos/kisspeptin labeling in animals given either
an estrogen implant (
b
), no treatment (
c
), or an i.v. injection (
d
). The percent kisspeptin cells that
had c-FOS labeling is shown in (
e
), with labeling in the POA given also, for comparison. The values
are means ± standard error and groups with different letters are signifi cantly (
P
< 0.05) different.
3V
third ventricle. Note that acute treatment increases c-FOS labeling, whereas chronic treatment
reduces c-FOS labeling, of kisspeptin cells; this shows that the same cells can respond to
both
nega-
tive and positive feedback effects of estrogen in opposite ways.
Scale bars
are 50
μ
m. From Smith
JT, Li Q, Pereira A, Clarke IJ. Kisspeptin neurons in the ovine arcuate nucleus and preoptic area are
involved in the preovulatory luteinizing hormone surge. Endocrinology. 2009 Dec;150(12):5530-8.
Reprinted with permission from The Endocrine Society
μ
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