Immunohistochemical localization of ghrelin in the sheep placenta. Representative immunohistochemical photomicrographs showing localization of ghrelin (b – f) in sheep placentomes collected at days 50 (b), 80 (c), 100 (d), 128 (e) and 135 (f). The insert in the bottom right corner (b) represents an example of a negative control. Positive immunostaining in the placenta was abolished (a) when the antiserum was pre-incubated with the immunizing peptide (ghrelin). Placentome sections mainly show positive immunostaining for ghrelin (brown) in the maternal compartment (M) and the trophectoderm (T), with few cells being immunopositive for ghrelin in the fetal compartment (F). The scale bars represent 50 μm.