In this study we describe for the first time, to our knowledge, the daily profile of BT in a insulin-deficient diabetic animal, and we demonstrate that diabetes not only causes a significant reduction in BT, but also the disruption of its daily rhythm (no rhythms with period between 20 and 28 hours), disturbance that intensifies with time, showing alterations in all rhythmic parameters, such as decreased MESOR, increased amplitude and shifted acrophases. The gene discussed is INS; the disease is diabetes mellitus.