A method of activating a nuclear receptor in an organism, includes the step of irradiating the nuclear receptor with light effective to activate the nuclear receptor to cause a biological effect in the organism; wherein, the nuclear receptor is not specific to a retina of the organism. The biological effect can be, i.e.: an influence exerted on: (a) a hypothalamic-pituitary-adrenal pathway, (b) a renin-angiotensin pathway, (c) a vagal-neuronal pathway, (d) a neuro-hormonal-immunal pathway, or (e) cellular metabolism. Other non-limiting examples of the biological effect include an alteration of the Warburg effect in the organism or an alteration of the response of the organism to ionizing radiation therapy, Photo Dynamic Therapy, surgical interventions, chemotherapy or sonodynamic therapy. The invention also encompasses the use of a laser device to perform the method and a laser device configured to perform the method.