Abstract Body: Our previous study suggested a potential role of (pro)renin receptor (PRR) in the regulation of Na⁺-Cl^- cotransporter (NCC) activity in the distal convoluted tubule (DCT). Here, we employed Slc12a3-CreERT2 to generate inducible DCT-specific deletion of PRR in mice (KO). As expected, the KO mice exhibited a 1.8-fold increase in renal NCC activity as reflected by HCTZ-induced natriuresis. Surprisingly, the KO mice developed metabolic and behavioral phenotypes. By calorimetry, 4-month-old male KO mice exhibited an enhanced energy expenditure as compared with floxed controls (oxygen consumption: 4172.5 ± 118.0 ml/kg/hr vs. 3303.5 ± 69.8 ml/kg/hr; CO₂ consumption: 3617.3 ± 87.8 ml/kg/hr vs. 2784.2 ± 58.5 ml/kg/hr; heat production: 20.4 ± 0.6 Kcal/kg/h vs. 16.2 ± 0.8 Kcal/kg/h, n = 5-9, p < 0.01), accompanied by enhanced locomotor activity (by 41.3%) and reduced body weight (30.2 ± 0.5 g vs. 28.0 ± 0.3 g, n = 5-9, p < 0.05). The changes in locomotor activity were confirmed by using radiotelemetry. Additionally, resident-intruder aggression test demonstrated that under basal condition, the KO mice exhibited a higher aggression rate as compared with floxed controls (80% in KO group vs. 30% in floxed group, n = 10). The KO mice also exhibited shorter clinch attack latencies, higher number of attacks and attack duration (attack latencies: 79.0 ± 17.6 s in KO group vs. 172.5 ± 5.3 s in floxed group; attack frequency: 3.4 ± 0.8 in KO group vs. 0.7 ± 0.4 in floxed group; attack duration: 10.1 ± 2.0 s in KO group vs. 1.1 ± 0.6 s in floxed group, n = 10, p < 0.01). Furthermore, the KO mice exhibited elevated plasma level of Klotho (321.4 ± 16.3 pg/ml in KO group vs. 254.1 ± 9.8 pg/ml in floxed group, n = 11-12, p < 0.01) that is known to promote energy expenditure in addition to its cardiorenal protective actions. In cultured renal HK2 cells, recombinant soluble PRR (sPRR-His) downregulated Klotho mRNA and protein expression by 29.8% and 37.9%, respectively. Overall, the present study uncovered a novel role of DCT PRR in the regulation of energy metabolism and behavior, part of which may be mediated by antagonism of Klotho action.