EFFECTS OF 3,3',4,4'-TETRACHLOROBIPHENYL ON THE DYNAMICS OF VITAMIN-A IN BROOK TROUT (SALVELINUS-FONTINALIS) AND INTESTINAL RETINOID CONCENTRATIONS IN LAKE STURGEON (ACIPENSER-FULVESCENS)

A single i.p. injection of 5 mu g 3,3',4,4'-tetrachlorobiphenyl (TCBP)/g body mass in adult brook trout (Salvelinus fontinalis) resulted in decreased (p < 0.0001) growth rate despite pair feeding. Plasma retinol decreased (p < 0.0037). Intestinal retinyl palmitate (RP) and 3,4-dehydroretinyl palmitate (DRP) concentrations decreased in TCBP-injected males (RP, p < 0.0143; DRP, p < 0.0009), whereas retinoid levels did not decrease significantly in TCBP-injected females. The RP:DRP ratio in trout liver increased (p < 0.0001). These results suggested that DRP is more sensitive than RP to the effects of TCBP. No significant differences in ovarian retinoids occurred in post-spawning trout. Field validation of the effects on intestinal retinoids was conducted with lake sturgeon (Acipenser fulvescens) caught at a contaminated site on the Des Prairies River near Montreal (St. Lawrence River population) and reference sturgeon taken from a site near the origin of the Ottawa River in La Verendrye Park. Intestinal retinoid concentrations were lower (RP, p < 0.0008; DRP, p < 0.0004) in the St. Lawrence River sturgeon. Our results demonstrate that a coplanar PCB is capable of altering vitamin A dynamics in several tissues and organs, and may cause a lowering of retinoids in the intestine.