Use of a new radioactive ligand, 7 alpha, 17 alpha-dimethyl[17 alpha-methyl 3H]19-nortestosterone for the estimation of androgen receptors in rat liver cytosol.

The use of the testosterone derivative, 7 alpha, 17 alpha-dimethyl[17 alpha-methyl 3H] 19-nortestosterone for the estimation of cytosolic androgen receptors in male rat liver is described. Use of this compound demonstrates binding which has a similar dissociation constant, maximum binding and steroid specificity to that seen with other synthetic testosterone derivatives. In contrast to previous data significant binding to the progesterone receptor also occurs and future studies with this ligand should employ triamcinolone acetonide to block such binding.