TCDD alters pituitary-adrenal function. I: Adrenal responsiveness to exogenous ACTH.
Plasma ACTH concentrations in 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-treated rats (50 micrograms/kg; single, oral dose) were 2.1-, 2.1-, 2.9-, 1.7-, 1.5-, 2.0- and 3.0-fold greater than control values, respectively, at days 1, 3, 5, 7, 10, and 14. At days 1 and 5 plasma corticosterone concentrations were increased 5.1- and 8.0-fold, respectively; whereas, at days 10 and 14 they were depressed to values of 50% and 39% of controls, respectively. Adrenal glands were excised from rats treated with TCDD and corticosterone production was assessed. Basal corticosterone concentrations produced by treated adrenals were depressed to 81%, 72%, and 71% of control values at days 5, 7, and 14, respectively. Corticosterone secretion by ACTH stimulated adrenals was equivalent to controls. These findings suggest that TCDD exposure decreases the bioactivity of the ACTH secreted by the anterior pituitary.
Bestervelt
L L
LL
Toxicology Program, School of Public Health, University of Michigan, Ann Arbor 48109-2029.
Cai
Y
Y
Piper
D W
DW
Nolan
C J
CJ
Pitt
J A
JA
Piper
W N
WN
D000311:Adrenal Glands / Q000187:drug effects*; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D003345:Corticosterone / Q000097:blood / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013268:Stimulation, Chemical
D000072317:Polychlorinated Dibenzodioxins; D000324:Adrenocorticotropic Hormone; D002786:Cholesterol Side-Chain Cleavage Enzyme; D003345:Corticosterone