Steroid-protein interactions in bovine plasma.
The binding of testosterone, corticosterone and 17alpha-hydroxyprogesterone by bull plasma protein was studied by equilibrium dialysis. Testosterone in bovine plasma was bound by a CBG-like protein and by a specific protein (testosterone-binding protein or TBP) of limited capacity and high affinity. The TBP was specific for C18 and C19 steroids with a 17 beta-hydroxy group. Precision of the steroid-protein binding measurements was tested and was satisfactory. The testosterone-binding capacity in bull plasma samples did not seem to be related to testosterone levels in peripheral plasma. Significant differences between bulls and cows with regard to the binding capacity were observed.
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D005260:Female; D006908:Hydroxyprogesterones / Q000097:blood*; D008297:Male; D011247:Pregnancy; D013739:Testosterone / Q000097:blood*
D001798:Blood Proteins; D006908:Hydroxyprogesterones; D013739:Testosterone; D003345:Corticosterone