Oxygen consumption rates of grunion (Leuresthes tenuis) embryos exposed to the petroleum hydrocarbon, benzo[a]pyrene.

Bioconcentration of [14C]benzo[a]pyrene and effects of unlabeled benzo[a]pyrene (BaP) accumulation on the routine oxygen consumption of embryonic grunion (Leuresthes tenuis) were studied. At Day 15, bioconcentration factors over dissolved BaP levels ranged from 249 to 466. Weight-specific respiration rates at Days 14-15 were significantly increased (P less than or equal to 0.05) at a mean BaP body burden of 0.51 ppm wet wt. Oxygen consumption rates of embryos containing 0.70 to 12.80 ppm BaP were not significantly different from control rates. Because in a previous study embryos containing 0.51 ppm BaP exhibited hatching and developmental rates similar to those of controls, their metabolic response to low-level hydrocarbon exposure may be an example of hormesis, an overcompensating metabolic regulation to inhibitory challenges.