Estrone-induced, prolactin-secreting and dopamine-sensitive rat pituitary tumor.
Prolactin (PRL)-secreting rat pituitary tumors were induced in female Fisher 344/Lis rats by s.c. implants of estrone (E1) pellets. Tumor growth was relatively fast and reached about 100 mg within 2 months. Ovariectomy at the time of E1 implants seemed to accelerate the growth of the tumors. Tumor cells in primary culture produced mainly PRL, while growth hormone (GH) release was about 2% of PRL production and the release of some other pituitary hormones did not exceed 1% of PRL values. Tumor cells were found to have high-affinity dopamine (DA) receptors. The addition of DA in vitro at 10(-10) M concentration stimulated PRL release, while at 10(-6) M concentration it inhibited the release of the hormone by more than 50% of control values. Histological, immunohistochemical and electron microscopical studies demonstrated the tumor to be composed mainly of maximally stimulated mammotrophs.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D002369:Castration; D002478:Cells, Cultured; D004298:Dopamine / Q000494:pharmacology*; D004970:Estrone / Q000633:toxicity*; D005260:Female; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000648:ultrastructure; D010907:Pituitary Hormones / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000139:chemically induced* / Q000378:metabolism / Q000648:ultrastructure; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344
D010907:Pituitary Hormones; D004970:Estrone; D011388:Prolactin; D001058:Apomorphine; D004298:Dopamine