Figure 4.

In vivo estrogen induction of PTTG and rat lactotroph tumors. (a) Representative normal rat pituitary (NI) and rat pituitary tumor (E₂). (b and c) Serum PRL and pituitary wet weight (b) and Northern blot analysis (c) of pituitary tissue extracts derived from estrogen-treated rats. β-Actin was utilized as the internal control. Ovx, ovariectomized controls. M, marker lane. *P < 0.001; **P < 0.01. (d and e) Reticulin fiber staining (broken circle) of rat anterior pituitary tissue at 24 hours (d) and 1 week (e) after commencement of estrogen infusion. (f and g) Reticulin stain (arrows) (f) and hematoxylin and eosin stain (g) of rat anterior pituitary tissue 4 weeks after estrogen infusion began. Widespread vacuolation, vascular lakes (g, arrow), nuclear pleomorphism and frequent mitosis (g, arrowhead) are visible. (h) pituitary bFGF immunoreactivity after 4 weeks of estrogen treatment. Original magnification, ×200. Reproduced with permission from Nature Medicine (37).