[The molecular basis for the steroid hormone actions in the kidney]

Steroid hormones such as mineralo- and glucocorticoids act as important regulators for the kidney to maintain the body fluid homeostasis. During the past 40 years, numerous investigations have been dedicated to the elucidation of precise mechanisms of steroid hormone actions in their target tissues including the kidney. Now it is well recognized that cellular actions of steroid hormones can be accomplished by two step processes, namely a specific receptor binding in the cytosol and/or the nucleus and a new protein synthesis through a gene transcription. The efforts for the isolation and purification of steroid hormone receptors have been also made and followed by the great successes of molecular techniques in the cDNA cloning and determination of amino acid sequences for them in recent years. The revealed high homology of the functional domains of receptors has renewed the issues of how tissue specificities of steroid hormone actions are determined. The identification of steroid-induced proteins and cellular steroid hormone metabolites would be also important issues to be studied.