In the body, the kidneys are responsible for the filtration of blood to regulate fluid volume and solute homeostasis. In turn, the kidney is a large contributor to the regulation of blood pressure and overall cardiovascular health. Most physiological functions exhibit a circadian rhythm, and disruption of these circadian processes is linked to many pathologies, including hypertension. I will be investigating the mechanisms by which the circadian clock gene BMAL1 influences renal function. Our lab has shown that BMAL1 in the distal segments of the nephron plays an important role in blood pressure regulation and sodium handling in a sex-specific manner. We have shown that male KS-BMAL1 knockout mice exhibit less sodium retention in response to a potassium depleted diet compared to control mice. We hypothesize that the BMAL1 knockout mice will demonstrate lower expression of two ion transporters, NKCC2 and pendrin, which might contribute to their lower sodium retention and lower blood pressure. I will be using bioassays to study these two transporters. My studies will add critical mechanistic data to help understand the role of BMAL1 in the kidney.