Fig. 1

Experimental design. Subtotally nephrectomised and healthy rats were randomised to 4 exposure groups for each scheduled sacrifice at day 28 (n = 10 rats in groups 1, 2, and 3; n = 5 in group 4) or day 56 (n = 9 in groups 1, 2, and 3; n = 5 in group 4) after the end of the 4-week treatment period. Animals in each group received a single daily intravenous injection of the respective gadolinium-based contrast agent at a dose of 0.6 mmol/kg body weight 4 times a week for 4 consecutive weeks. At scheduled sacrifice, blood and tissues were harvested for Gd determination by inductively coupled plasma/mass spectrometry. As not all the animals completed the study, the sample size was reduced to 8 rats in groups 1 and 2, to 9 in group 3 at day 28, and to 8 in groups 1 and 3, and 7 in group 2 at day 56. Blood was sampled for urea and creatinine determinations predose (day − 4), at the end of dosing (day 32) and before scheduled sacrifice (day 53 and day 81)