Gustafsson et al cloned the first (partial) cDNA of a nuclear receptor, the glucocorticoid receptor; the unique probes making this possible were the poly- and monoclonal antibodies against the glucocorticoid receptor developed by the Gustafsson lab. Another important milestone was the structure determination of the DNA-binding domain of the glucocorticoid receptor, the first ever nuclear receptor structure to be solved. During the recent fifteen years, Gustafsson has continued to be responsible for paradigm shifts in the field of nuclear receptor research. It was Gustafsson who first identified physiological ligands for a so called “orphan receptor”, namely fatty acids for the peroxisome proliferator activated receptor (PPAR), thereby integrating fatty acids into molecular endocrinology. Furthermore, Gustafsson discovered OR-1, later renamed LXRβ, an oxysterol activated nuclear receptor of paramount significance in e g regulation of cholesterol homeostasis and brain development.

Finally, and most importantly, Gustafsson and colleagues made the completely unexpected discovery of estrogen receptor β, a second estrogen receptor which has turned out to have functions far outside reproductive physiology and to be a very promising target in pharmaceutical development of novel drugs.