Random-fed insulin and proinsulin plasma concentrations in RC-fed mice. Plasma insulin and proinsulin were measured following collection from the tail vein (before culling) and aorta (immediately post mortem) of RC-fed Ctrl (black) or KO [green, males (A and B); purple, females (C and D)] mice aged over 21 wk. The ratio plasma insulin/plasma proinsulin is shown in E; n = 7 Ctrl and 8 KO (males), 10 Ctrl and 9 KO (females).