5. UCP3S and UCP3L mRNA levels are measured by quantitative polymerase chain reaction at the Department of Pharmacology, University of Milan. Presence of beta-3 adrenoceptor in adipose tissue is evaluated by immunohistochemistry by the avidin-biotin peroxidase technique using monoclonal anti-human beta 3-adrenoceptor antibody at the Department of Human Anatomy, University of Ancona.