Figure 3.

Depletion of Corticotropes in invloxP/+;POMC-Cre Pituitaries. A–D, Sagittal pituitary sections stained for Tpit (green) and nuclear Hoechst (blue) reveal slight corticotrope loss in invloxP/+;POMC-Cre P0 pituitaries (B) compared with control invloxP littermates (A). A more severe depletion of corticotropes is observed at 19 weeks of age (D compared with C). Red arrows indicate background autofluorescence of red blood cells. E, POMC (green) and Cre (red) immunofluorescence staining of 19-week-old invloxP/+;POMC-Cre pituitaries revealed rare occurrence of Cre-positive corticotropes, in striking contrast to the expected 53% Cre penetrance (Figure 2B). On the contrary, IL melanotropes are mostly double positive for POMC and Cre (right insets).