Steroid-Binding Proteins in Primate Plasma*

We used immunological techniques to compare the serum corticosteroid-binding globulins (CBG) and testosterone-estradiol-binding globulins (TeBG) of Old World primates (man, chimpanzee, cynomologus, and rhesus), New World monkeys (squirrel and owl), and prosimians (galago and lemur). Four different antihuman TeBG antisera could not differentiate human and chimpanzee TeBG and recognized the galago and lemur TeBG as similar as well as the rhesus and cynomologus TeBG, as similar. Western blots of serum subjected to sodium dodecyl sulfate gel electrophoresis, with detection by an anti-TeBG antiserum, showed similar patterns of distribution of the two molecular species of TeBG for all of the New World primates and the owl monkey. The abundance of the two TeBG species was reversed in squirrel monkey serum, while lemur and galago displayed only a single band. Four different antihuman CBG antisera grouped together the CBGs of human and chimpanzee, rhesus and cynomologus, and lemur and galago. The squirrel monkey h...