Reduced STAT5 expression in hypothalamic neurons in Stat5fl/fl; Nestin-Cre male mice.

(A) Immunohistochemical analyses with αSTAT5 antibodies were performed on hypothalamic tissues from Stat5fl/fl control (ff, left panels) and Stat5fl/fl; Nestin-Cre (ffnc, right panels) mice. Note the prominent expression of STAT5 isoforms in discrete neurons and the dramatic reduction in STAT5-positive cells in ffnc mice. Upper panels show hypothalamic sections rostral to those shown in lower panels. 3V = third cerebral ventricle, ME = median eminence, f = fornix; all other abbreviations as defined in the text. (B) Immunostaining for STAT5 (green, top), the neural marker, Hu (red, middle) and merged images (bottom) in the LHA ff and ffnc animals. This demonstrates the co-localization/expression of STAT5 in neurons of ff animals and the absence of STAT5 from many Hu-positive neurons in ffnc mice. (C) Total RNA from microdissected hypothalamic subregions of ff and ffnc mice was subjected to semi-quantitative real-time PCR for STAT5A and STAT5B mRNA expression, confirming the reduction in the expression of both STAT5 isoforms in each region.