Embryonic expression of the leptin receptor gene in mesoderm-derived tissues.

Leptin acts on the hypothalamus to reduce food intake and on a number of non-neuronal tissues via specific receptors (Lepr). The use of in situ hybridisation to map the Lepr gene in pre-natal mice revealed transcripts in the yolk sac in various structures of the central nervous system and in mesoderm-derived tissues, such as cartilage/bone primordia and musculoaponeurotic laminae. At later stages, significant amounts of Lepr were expressed in the region surrounding the developing eye of the embryo. Lepr was also found to be expressed in the choroid, sclera and connective tissues of the limbus in the adult eye. In conclusion, we have identified new targets for leptin action during embryogenesis and adulthood.