Estrogen and prothrombin synthesis: effect of estrogen on absorption of vitamin K,

JOLLY,DENNIS W., CAROLYN CRAIG, ANDTHOMAS E. NELSON, JR. Estrogen and prothrombin synthesis: effect of estrogen on absorption of vitamin K,. Am. J. Physiol. 232(l): H12H17, 1977 or Am. J. Physiol: Heart Circ. Physiol. l(1): H12H17, 1977. -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 ,ug/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 pg/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 K, 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 rug and 11.8 pg vitamin K,, respectively. Nontreated control castrate male and female rats absorbed 0.0 pg and 1.2 ,ug, respectively, during a 24O-min collection period. Use of radioactive vitamin K, in similar experiments confirmed these results. Estrogen-treated castrate males absorbed vitamin K, at the rate of 30-40 pg/g lymph whereas nontreated control males absorbed only about 6 pg/g lymph.