Estrogen and prothrombin synthesis: effect of estrogen on absorption of vitamin K1.
Intact male and female albino rats fed a vitamin K-deficient diet develop a plasma prothrombin-proconvertin deficiency. Male rats respond with a precipitous drop to approximately 20-30% of normal plasma levels within 2-5 days, whereas female rats respond at a slower rate. Ethynylestradiol, 5-10 mug/day, or castration, reduces the progressive decline of plasma prothrombin-proconvertin seen in nonsupplemented intact male rats. The response of castrate females differs little from the response of intact females. Ethynylestradiol, 5-10 mug/day, affects both castrate males and females similarly, limiting the prothrombin-proconvertin decrease to about 13% below control value after 14 days. Intestinal absorption of vitamin K1 measured in the thoracic duct lymph of pentobarbital-anesthetized castrate male and female rats was shown to increase significantly after estrogen treatment. Estrogen-treated castrate male and female rats absorbed 25.8 mug and 11.8 mug vitamin K1, respectively. Nontreated control castrate male and female rats absorbed 0.0 mug and 1.2 mug, respectively, during a 240-min collection period. Use of radioactive vitamin K1 in similar experiments confirmed these results. Estrogen-treated castrate males absorbed vitamin K1 at the rate of 30-40 mug/g lymph whereas nontreated control males absorbed only about 6 mug/g lymph.
D000818:Animals; D002369:Castration; D004305:Dose-Response Relationship, Drug; D004967:Estrogens / Q000494:pharmacology*; D004997:Ethinyl Estradiol / Q000494:pharmacology; D005167:Factor VII / Q000096:biosynthesis; D005260:Female; D007020:Hypoprothrombinemias / Q000209:etiology*; D007413:Intestinal Mucosa / Q000378:metabolism; D008196:Lymph / Q000378:metabolism; D008297:Male; D011516:Prothrombin / Q000096:biosynthesis*; D051381:Rats; D014812:Vitamin K / Q000378:metabolism*; D014813:Vitamin K Deficiency / Q000150:complications*
D004967:Estrogens; D014812:Vitamin K; D004997:Ethinyl Estradiol; D005167:Factor VII; D011516:Prothrombin