Subcellular localization of Ob-R (A) and Ob (B) proteins in an equine IVM/ICSI-derived embryo. The sample is representative of confocal investigations on 25 serial optical sections (step size = 0.45 μm) performed on all examined embryos. A 4-cell stage embryo is shown obtained after IVM culture in presence of 100 ng/ml leptin. In surface planes, in the lower (planes n° 1 to 5) and upper (planes n° 19 to 25) parts of the embryo, a labeling in clumps/clusters can be seen while in planes nearer the equatorial position (planes n° 6 to 18), an intense fluorescence is observed beneath the oolemma together with uniform distribution of Ob (A) and Ob-R (B) staining within the cytoplasm. Scale bar represent 60μm.