Figure 3.

Chemogenetic activation of kisspeptin neurons also resulted in higher LH induction in HFD mice. A, Kiss1-Cre⁺-EGFP colocalization with virally transduced hM3Dq-mCherry (red) 2 weeks after injection demonstrates DREADDs targeting to kisspeptin neurons. B, Kisspeptin neuron activity, assessed by cFOS expression, in control animals; a, GFP immunoreactivity identified kisspeptin neurons in kisspeptin-GFP mice; b, cFOS expression in arcuate nucleus; c, overlap to determine percentage of kisspeptin neurons with cFOS. C, Kisspeptin neuron activity after injection of CNO in DREADD-infected animals; a, GFP; b, colocalization of mCherry and GFP, indicating rate of infection; c, cFOS; d, colocalization of cFOS and GFP. D, LH secretion after intraperitoneal injection of 0.3 mg/kg (n = 6) or 1 mg/kg (n = 4) CNO demonstrates dose-dependent effects. * indicates statistical difference in response to different CNO concentration at the same time point. E, LH secretion in response to intraperitoneal injection of 0.3 mg/kg CNO in Kiss1-Cre⁻ animals infected with AAV9 hM3Dq-mCherry (CTR n = 4, HFD n = 4) and in Kiss-Cre⁺ infected with AAV9 hM3Dq-mCherry (CTR n = 6, HFD n = 5) after injection with saline demonstrate specificity of response. F, LH levels in response to 0.3 mg/kg CNO injection (CTR, n = 6; HFD, n = 5). * indicates statistically significant difference (p = 0.043) between CTR and HFD at the same time point. G, Fold change of LH from basal levels in response to 0.3 mg/kg CNO injection. * indicates significant difference between CTR and HFD at the peak, p = 0.00119).