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Effects of a large dose of oestradiol on antithrombin III metabolism in male and female dogs
Author(s) -
KOBAYASHI N.,
TAKEDA Y.
Publication year - 1977
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1977.tb01622.x
Subject(s) - endocrinology , medicine , antithrombin , metabolism , plasma concentration , chemistry , heparin
. Canine antithrombin III (AT) metabolism was studied in twenty healthy dogs of both sexes first under control conditions, using 125 I‐AT as a tracer, then, in the same dogs after 20 mg oestradiol intramuscularly and another 20 mg 7 days later. Under control conditions the plasma AT concentration and the amount of plasma AT (x̄) were greater in males than females. The plasma half‐lives of 125 I‐AT averaged 2.14 ± 0.09(SD) days in males and 1.97 ± 0.05(SD) days in females and were significantly different. The fractional catabolic rate of plasma AT ( j 3p ) was lower in males than in females, but the amount of plasma AT catabolized ( j 3p X̄) (synthesis rate) was not significantly different (averaging 20 ± 3.7 (SD) in males and 18 ± 2.2(SD) mg/kg/day in females). The total body AT ( x̄ + ȳ ) was greater in males than in females; average values 55 ± 7.5(SD) and 46 ± 5.2(SD) mg/kg, respectively. Under the influence of oestradiol, the plasma AT concentration and AT( x̄ ) decreased in both sexes, but the plasma half‐lives of 125 I‐AT showed no appreciable changes. The values of AT( j 3p ) and AT( j 3p X̄ ) were significantly decreased in both sexes; average values of the latter being 14 ± 1.5(SD) in males and 12 ± 2.2(SD) mg/kg/day in females. AT( x̄ + ȳ ) averaged 43 ± 3.8(SD) in males and 33 ± 6.3(SD) mg/kg in females and were significantly decreased. These results indicate that the decreased values in plasma AT concentration, x̄ and x̄ + ȳ following oestradiol administration are due to the decreased synthesis rate of AT and not to an increased catabolic rate.