Studies on the transfer of steroid hormones across the blood-cerebrospinal fluid barrier in the Rhesus Monkey.
Indwelling canulae were placed in the lateral ventricles of the brains of six adult male rhesus monkeys, and the movement of estradiol-17beta (E2), testosterone (T), and 5alpha-dihydrotestosterone (DHT) across the blood-cerebrospinal fluid (CSF) barrier was measured. Serial samples of blood and CSF were collected every 30 minutes during a 6 hour infusion of the tritiated steroids, and the quantity of free steroid in the blood and CSF was determined by recrystallization to constant specific activity. During the course of the 6-hour infusion, the average CSF concentration of steroid, expressed as dpm/ml, was about 3.5% of the concurrent plasma level of E2, 1.6% of the concurrent plasma level of T, and 0.08% of the concurrent plasma level of DHT. It is proposed that these differences in steroid transfer can be attributed to differential binding of these steroids to testosterone-estrogen-binding globulin (TeBG) in plasma.
D000818:Animals; D001812:Blood-Brain Barrier; D002404:Catheterization; D004958:Estradiol / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D006914:Hydroxysteroids / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D008253:Macaca mulatta; D008297:Male; D013739:Testosterone / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism*; D013997:Time Factors
D006914:Hydroxysteroids; D013739:Testosterone; D004958:Estradiol