Rapid [14C]heptachlor clearance from body stores of ovines: ingested mineral oil and parenteral trans-stilbene oxide lack effects.
Recently we reported elimination of radioactivity from [14C]heptachlor from body stores of lactating ovines, mainly into excreta rather than milk, contrasting sharply with bovines. To further assess heptachlor metabolism and clearance by ovines, 12 fine-wool wether lambs (41 +/- 3 kg) housed in metabolism stalls were fed pelleted alfalfa hay (96%) plus molasses (3%) ad libitum and were dosed i.p. once with [14C]heptachlor (1.643 mg/kg body wt; sp. act. = .89 microCi/mg). Feces and urine were collected separately and quantitatively. Light mineral oil was mixed with feed (5 g/100 g) of six lambs and trans-stilbene oxide, an inducer of biotransformational enzymes, was administered i.p. (4 g/hd initially; 2 g/hd daily thereafter) through 20 d to three lambs given each mineral oil treatment, in 2 x 2 factorial arrangement. Feces, urine, blood, bile and body tissues were assayed for total 14C activity. Radioactivity (heptachlor and [or] metabolites) eliminated into excreta during 21 d amounted to 34 to 36% of dose administered, of which 67% appeared in urine and 33% in feces. Biological half-time for elimination into excreta was 11.3 d [Kel = -.061/d], similar to 11.7 d we reported for lactating ewes. Clearance from blood had T1/2 = 14 d. Neither mineral oil nor trans-stilbene oxide altered rate or route of 14C activity excreted or concentrations of 14C activity in blood. Results confirmed that ovines eliminate heptachlor much more rapidly than bovines.
Smith
G S
GS
Dept. of Anim. and Range Sci., New Mexico State University, Las Cruces 88003.
Rozman
K K
KK
Hallford
D M
DM
Rankins
D L
DL
Khan
M F
MF
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D006533:Heptachlor / Q000378:metabolism / Q000493:pharmacokinetics*; D008297:Male; D008657:Metabolic Clearance Rate / Q000187:drug effects; D008899:Mineral Oil / Q000494:pharmacology*; D012756:Sheep / Q000378:metabolism*; D013267:Stilbenes / Q000494:pharmacology*
D013267:Stilbenes; D006533:Heptachlor; D008899:Mineral Oil; C025906:stilbene oxide