The Renal Function of the Wild Rodent Cerradomys goytaca Reveals Adaptations in the Mechanisms of Urinary Concentration and Solute Excretion

The rodent Cerradomys goytaca is endemic to the coastal sandplains (restingas) of Brazil. This study aimed to investigate the renal morphology and physiology of this species to elucidate the possible mechanisms involved in urinary concentrating capacity and renal solute handling. Ten female specimens of C. goytaca werecompared with twenty female Wistar Rattus norvegicus . Feed intake and urinary flow were determined. The following parameters indicative of renal function were evaluated: clearance, fractional excretion, and urinary excretion of creatinine, osmolality, urea, sodium, potassium, and glucose. Additionally, morphological analyses of the kidneys were performed to evaluate cortical and medullary structure. C. goytaca showed a significantly higher renal mass index despite a lower nephron count compared to R. norvegicus . The species demonstrated the ability to produce more concentrated urine, with lower urinary flow and greater water reabsorption. Higher urinary excretion of sodium, potassium, and glucose was also observed. Together, these results suggest adaptive mechanisms for electrolyte and glucose handling, as well as water conservation, that may support the survival of this species in its natural habitat.