The effect of repeated gavage doses of fumonisin B-1 on the sphinganine and sphingosine levels in vervet monkeys

Fumonisins occur widely around the world in maize products intended for hum an and animal consumption posing a health hazard. Direct measurement of fum onisins in physiological fluids as a biomarker of exposure is not practicab le, however fumonisins disrupt sphingoid metabolism by inhibition of sphing anine N-acyltransferase. In this study the disruption in sphinganine (Sa) a nd sphingosine (So) levels in plasma and urine was measured in vervet monke ys (Cercopithecus aethiops) dosed with repeated gavages of 1 mg fumonisin B -1 (FB1)/kg body weight three times/week continuously over a 51-day period. The plasma Sa/So ratio reached a maximum (mean of 4.3) after 30 days in th e dosed monkeys with a three-fold increase above the ratio of the control m onkeys and then declined slowly to double the value in controls after 51 da ys. The lack of a clear elevation in urinary Sa/So ratios after 51 days of multiple exposure in the dosed monkeys indicates that the plasma ratio is m ore sensitive than urinary changes in monkeys. This is confirmed by the pla sma levels of liver function enzymes of which aspartate transaminase, gluta myl-transferase and lactate dehydrogenase were increased in the dosed monke ys, while the plasma indicators of renal function were not increased above the levels in the control monkeys. Thus repeated low doses of FB, can cause sustained disruption of sphingoid metabolism. (C) 2001 Elsevier Science Lt d. All rights reserved.