The development of androgen responsiveness in the submandibular gland of normal and androgen-resistant (Tfm) mice of different ages was studied after varying hormonal treatments. Total esteroproteolytic (tamase) activity of submandibular gland homogenates was used as a marker for androgen action. Newborn mice of all four genotypes (normal male, normal female, carrier Tfm females, and Tfm males) were resistant to androgen. However, at 3 weeks of age the capacity to develop a tamase response appears in normal and carrier Tfm animals given androgen and rapidly rise to maximal levels. The level in the normal animal is regulated thereafter primarly by the level of circulating androgen. In contrast, the tamase response in the Tfm male of all ages and under all androgen regimens was minimal.