Incorporation of radioactive 35SO4(2-) into immunoreactive pituitary lutropin

The terminal hexosamines of bovine pituitary lutropin are thought to contain a sulfate moiety. In order to test this, a biosynthetic approach was adopted. When rat and buffalo (bovine) pituitaries were incubated with radioactive 35SO4(2-) for 2 h in vitro it was observed that radioactivity test incorporated into trichloroacetic acid-precipitable proteins. When the radioactive proteins were treated with an anti-sheep lutropin serum, radioactivity was found in the immunoprecipitate. The incorporation into rat lutropin like material was very marginal while it was very significant in the case of buffalo lutropin.