Fasting induced kisspeptin signaling suppression is regulated by glutamate mediated cues in adult male rhesus macaque (Macaca mulatta)

作者：Shamas Shazia; Khan Saeed ul Hassan; Khan Muhammad Yousaf; Shabbir Nadia; Zubair Hira; Shafqat Saira; Wahab Fazal; Shahab Muhammad^*

来源：Neuropeptides, 2015, 52: 39-45.

DOI：10.1016/j.npep.2015.06.005

• Kisspeptin
• Glutamate
• Fasting
• Rhesus macaque

Kisspeptin signaling is suppressed by short term fasting. It has been reported that hypothalamic Kiss1 and Kiss1r mRNA expression decreased after 48 h of fasting in male rhesus monkey. But the mechanism involved in the reduction of kisspeptin signaling after 48 h of fasting is unknown. Recent studies have suggested the role of afferent excitatory and inhibitory pathways in the regulation of kisspeptin neurons. Therefore, this study was designed to observe the changes in the glutamate and GABA signaling during fed and 48 h fasting states by performing immunofluorescence to examine the interaction of kisspeptin neurons with NR1 subunit of NMDA receptors and by performing SYBR green gRT-PCR to measure and quantify the levels of Kiss1, Kiss1r, NR1 and GAD67 mRNA in the POA and MBH of adult male rhesus macaque (Macaca mulatto) during 48 h of fasting (n = 2) and fed ad libitum (n = 2). Plasma testosterone (p < 0.05) and blood glucose levels were significantly (p < 0.001) decreased after short term fasting. Our results clearly showed that expression of hypothalamic Kiss1, Kiss1r and NR1 mRNA was significantly (p < 0.05) reduced in adult male rhesus monkeys which were fasted for 48 h as compared to those which were fed ad libitum. There was no clear difference in the GAD67 mRNA contents between the two groups. Number of kisspeptin neurons and the interactions of kisspeptin neurons with NR1 were significantly (p < 0.05) reduced after 48 h fasting. These observations suggest that decreased kisspeptin signaling during fasting may occur due to reduction in glutamatergic inputs to kisspeptin neurons. Our results also suggest that fasting induced suppression of kisspeptin signaling is not mediated through GABAergic neurons.

• 出版日期2015-8