Estrogenic compounds decrease growth hormone receptor abundance and alter osmoregulation in Atlantic salmon

► E2 or NP compromises morphological and physiological changes during smolting. ► Physiological changes include a shift from ion-secretion to ion-uptake. ► The effects of E2 and NP are brought about by reducing GHR abundance and activity. ► E2 provides an osmoregulatory function in addition to its reproductive role.