Open AccessEstrogen Receptor Levels and Tumor Growth in a Series of Pituitary Clonal Cell Lines in Rats
Author(s) -
Fujimoto Nariaki,
Watanabe Hiromitsu,
Ito Akihiro,
Inoue Kinji
Publication year - 1991
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1991.tb01817.x
Subject(s) - endocrinology , estrogen , estrogen receptor , pituitary tumors , medicine , cell growth , pituitary gland , tumor cells , biology , cell culture , cancer research , cancer , genetics , hormone , breast cancer
Four kinds of in vitro clonal pituitary tumor cell lines named MtT/Se, MtT/SM, MtT/S and MtT/ E, each of which shows different sensitivity to estrogen on proliferation, were inoculated into fat pad of ovariectomized rats and estrogen‐loaded ovariectomized rats at 10 5 and 10 6 cells/site. They formed tumor with average latency ranging from 30 to 71 in ovariectomized rats and 13 to 63 days in estrogenized rats inoculated with 106 cells. MtT/Se was highly sensitive to estrogen for growth, and MtT/SM also grew well in estrogenized rats. With MtT/S and MtT/E, there was no significant shortening of average tumor latency in estrogenized rats. In vivo , the cytosolic estrogen receptor (ER) levels of MtT/Se, SM, S and E were measured to be 452 ±66, 370 ±115, 260 ±16 and 83 ±8 fmol/ mg protein, respectively. In vitro , however, the lowest ER level was noted in MtT/Se. Histologically, all four tumors grown in rats were composed of homogeneous round cells, and MtT/Se contained particularly large nucleated cells. In MtT/E, the cells appeared to be changing into ftbromatous cells. Three cell lines except MtT/E maintained the function of hormonal secretion in vivo as well as in vitro . Serum GH level was increased in rats with MtT/Se and MtT/S. Increased levels of both prolactin and growth hormone were measured in sera of rats with MtT/SM. Increases of hormones as well as tumor sizes were promoted by the estrogen.