The effects of 17 alpha-methyltestosterone (T alpha), T4, or cortisol (F) on tissue kallikrein in the rat submandibular gland and renal cortex were measured. Castrated male or normal female Sprague-Dawley rats were treated with T alpha or T4 for 2 weeks. In addition, F, T alpha, or T4 was given to adrenalectomized female rats for 2 weeks. In the submandibular glands of male rats, castration resulted in a significant reduction of both kallikrein-like alpha-N-tosyl-L-arginine methyl ester (Tos-Arg-OMe) esterase activity and immunoreactive kallikrein content. Treatment with T alpha or administration of T4 significantly increased Tos-Arg-OMe esterase activity and immunoreactive kallikrein over that in the castrated rats receiving vehicle. Both the Tos-Arg-OMe esterase activity and kallikrein content of the submandibular glands of normal female rats were increased significantly by T alpha or T4. However, T alpha or T4 either significantly reduced or had no effect on renal Tos-Arg-OMe esterase activity or kallikrein content in castrated male or normal female rats. Adrenalectomy had no effect on submandibular gland Tos-Arg-OMe esterase activity and kallikrein content in the female rat, but F or T alpha significantly increased submandibular gland Tos-Arg-OMe esterase activity and kallikrein content. These adrenalectomized female rats showed a marked increase in renal cortical Tos-Arg-OMe esterase activity and kallikrein content, and F, T alpha, or T4 markedly decreased both esterase activity and immunoreactivity. These data show that T alpha, T4, and F modulate both kallikrein-like activity and quantity, but in a generally opposite way in the rat submandibular gland vs. the kidney.