Distribution of vitamins A (retinol) and E (α-tocopherol) in polar bear kidney: Implications for biomarker studies

► Examines the distribution of retinol and α-tocopherol in the polar bear kidney. ► No significant difference between medial and polar renculi. ► Significant differences between cortex and medulla for both vitamins. ► One should take precautions when analyzing vitamins in polar bear kidneys.