Expression of hypothalamic kisspeptin
 neurokinin B
 and dynorphin A neurons attenuates in female Zucker fatty rats

Kimihiko Nakao
Kinuyo Iwata
Toshiyuki Takeshita
Hitoshi Ozawa

Zucker fatty (ZF) rats are considered to be an obese model due to leptin receptor abnormality and such rats show infertility. Pulsatile gonadotropin-releasing hormone/luteinizing hormone (LH) secretion
 which is important for follicular development in females
 is considered to be controlled by KNDy neurons coexpressing kisspeptin
 neurokinin B (NKB)
 and dynorphin A (DynA)
 encoded by Kiss1
 Tac3
 and Pdyn
 respectively
 in the hypothalamic arcuate nucleus (ARC). The purpose of this study is to examine the expression of KNDy neurons in female ZF rats by histochemical approach because pulsatile LH secretion is suppressed. Zucker lean (ZL) rats served as a control group. Animals were ovariectomized and subcutaneously implanted with a silicon tube containing estradiol to produce plasma level of estradiol during diestrus. Plasma LH levels decreased in ZF rats compared with ZL rats. The expressions of each mRNA (Kiss1
 Tac3
 and Pdyn) and each peptide (kisspeptin
 NKB
 and DynA) in the ARC significantly decreased in ZF rats compared with ZL rats. However
 the number of Kiss1 neurons in the anterior ventral periventricular nucleus did not significantly differ between the two groups. These results suggest that dysfunction of leptin signaling negatively affects KNDy neurons in the ARC
 resulting in reproductive dysfunction caused by suppression of the LH pulse.

Neuroscience Letters

Elsevier Ireland Ltd

665

10.1016/j.neulet.2017.12.002

https://doi.org/10.1016/j.neulet.2017.12.002