Colocalization of prolactin and proliferating cell nuclear antigen in the anterior pituitary during estrogen-induced pituitary tumors.
Chronic estrogen treatment induces prolactin (PRL)-secreting pituitary tumors in laboratory animals. To determine earlier events of tumorigenesis, we studied cell proliferation in the pituitary following 7-30 days of estrogen administration in Fischer 344 rats. Immunohistochemical localization of proliferative cells by proliferating cell nuclear antigen (PCNA) staining and lactotropes by PRL staining revealed that estrogen treatment caused a time-dependent increase in the number of proliferative cells and lactotropes. Although the increase in lactotropic cell number paralleled the increase in PCNA-reactive cell number, only approximately 30% of lactotropes reacted simultaneously with the PCNA antibody. These results indicate that a subset population of lactotropes proliferates under the influence of estrogen during tumorigenesis.
Banerjee
S K
SK
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman 99164-6520.
De
A
A
Sarkar
D K
DK
D000818:Animals; D002455:Cell Division; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D010911:Pituitary Neoplasms / Q000139:chemically induced / Q000378:metabolism*; D011388:Prolactin / Q000032:analysis*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis*; D051381:Rats; D011916:Rats, Inbred F344
D018809:Proliferating Cell Nuclear Antigen; D004958:Estradiol; D011388:Prolactin