title: Effects of petroleum on adrenocortical activity and on hepatic naphthalene-metabolizing activity in mallard ducks.
abstract: Unstressed mallard ducks (anas platyrhychos), given uncontaminated food and maintained on a short photoperiod, show two daily maxima in plasma corticosterone concentration ([B]) on occurring early in the light phase and a second just before the onset of darkness. After one week of exposure to food containing 3% (v/w) South Louisiana crude oil, plasma [B] were significantly lowered throughout the day. Similar abrupt declines in plasma [B] also occurred during the first 10 days of exposure to food containing 1% and 0.5% crude oil. Although the plasma [B] in birds consuming food contaminated with 0.5% crude oil increased between 10 and 50 days of exposure, the concentration after 50 days was still lower than normal. During the same interval, normal plasma [B] were restored in birds consuming food containing 1% and 3% crude oil. Significant increases occurred in the naphthalene-metabolizing properties of hepatic microsomes prepared from birds acutely exposed to all levels of petroleum-contaminated food and elevated levels were sustained throughout the first 50 days of exposure. Birds given food containing 3% crude oil for more than 50 days, however, showed steady declines in hepatic naphthalene-metabolizing activity. After 500 days, the activity was similar to that found in contemporaneous controls. During the same interval the plasma [B] increased until the levels were higher than normal after 500 days of exposure; at this time, an inverse relationship, similar to that seen during the first week of exposure to contaminated food, was once more established between plasma [B] and the concomitant hepatic naphthalene-metabolizing activity.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002940:Circadian Rhythm / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D004372:Ducks / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D009281:Naphthalenes / Q000378:metabolism; D010578:Petroleum / Q000633:toxicity*
chemical_list: D009281:Naphthalenes; D010578:Petroleum; D003345:Corticosterone