CYTOCHROMES P450,NUCLEAR RECEPTORS AND FIBROBLAST GROWTH FACTORS- NEW ENDOCRINE AXES AS POTENCIAL DRUG TARGETS TO TREAT METABOLIC DISORDERS

Abstract

background Coordinate action of endocrine and nervous system enables adaptation of higher organisms to constant changes in the environment. Fibroblast growth factors (FGFs) primarily regulate embryonic and organ development, however, FGF19 subfamily members despite the name act in an endocrine fashion. The studies of endocrine FGFs resulted in the discovery of new endocrine axes, composed of small lipophilic molecules and members of three protein families: cytochromes P450, nuclear receptors, and FGFs. Cytochromes P450 are enzymes responsible for metabolism of different lipid molecules. Nuclear receptors bind lipid metabolites and act as metabolic sensors. They become activated and as transcriptional factors turn on expression of endocrine FGFs. eFGFs regulate metabolic pathways in target organs that express specific FGF receptor/coreceptor pair. FGF15/19 is expressed in the small intestine and is involved in the postprandial bile acid negative feedback loop in the liver. FGF21 is liver-borne fasting hormone that induces fat utilization. FGF23 is expressed in bone and acts on kidney to regulate phosphate and vitamin D metabolism.Conclusions We describe herein three new endocrine axes that were probably developed for fine tuning metabolite concentration within narrow physiological limits and prevent their toxicity in excess. They play important role in the pathophysiology underlying diverse metabolic disorders and are expected to be potential targets for therapeutic interventions.