Fifty years ago: The quest for steroid hormone receptors.

In 1963 Peter Karlson put forward the revolutionary "hormone-gene" hypothesis, which would change drastically the way in which steroid hormones were thought to act at the time. From a historical perspective, this review relates the acceptance of this initially controversial idea, the discovery of the steroid receptors and the key experiments that have led to the current understanding of the mechanism of steroid hormone action. It shows how, over 50years, the field has widened beyond all expectation and has contributed to major advances not only in endocrinology, but also in molecular biology, pharmacology and therapeutics.