Ohi Y, Yoshida H
Department of Pathology, Faculty of Medicine, Kagoshima University, Japan.
Virchows Arch B Cell Pathol Incl Mol Pathol. 1992;62(6):365-70. doi: 10.1007/BF02899705.
The influence of estrogen on mammary carcinogenesis was studied in female Sprague-Dawley rats ovariectomized at the age of 36 days and given injections of 17 beta-estradiol (group I:0, II:1, III:10, IV:100, V:1000 micrograms/2 days) between the ages of 36 and 250 days and a single oral dose of 20 mg of 7,12-dimethylbenz(a)anthracene (DMBA) at the age of 50 days. No palpable mammary carcinomas were detected up to the age of 135 days. At the age of 135 days, each group was divided into two subgroups (a and b). Rats of the second subgroup (Ib, IIb, IIIb, IVb and Vb) were given additional injections of progesterone (P; 4 mg/2 days) between the ages of 135 and 250 days. At the age of 250 days, the incidence of mammary carcinoma was significantly higher in rats from group IIIb than in groups Ib and IIIa, and that in group IVa was also higher than in group Ia. The incidence in group IVb was significantly lower than in group IVa. The carcinomas in group IIIb were palpable papillo-tubular adenocarcinomas and those in group IVa were secretory micro-adenocarcinomas. These results indicate that the induction of mammary carcinomas by DMBA is totally inhibited by ovariectomy and/or high doses of estrogen, but that mammary carcinomas are initiated by DMBA under hormonal conditions in which suitable levels of estrogen are present. They also suggest that the growth of DMBA-induced mammary carcinomas in the rats from group III were accelerated by additional injections of P and that those in rats from group IV were inhibited by additional P.(ABSTRACT TRUNCATED AT 250 WORDS)
在36日龄时对雌性斯普拉格-道利大鼠进行卵巢切除，并于36至250日龄期间给它们注射17β-雌二醇（I组：0，II组：1，III组：10，IV组：100，V组：1000微克/2天），并在50日龄时单次口服20毫克7,12-二甲基苯并(a)蒽（DMBA），以此研究雌激素对乳腺癌发生的影响。在135日龄之前未检测到可触及的乳腺癌。在135日龄时，每组分为两个亚组（a和b）。第二亚组（Ib、IIb、IIIb、IVb和Vb）的大鼠在135至250日龄期间额外注射孕酮（P；4毫克/2天）。在250日龄时，IIIb组大鼠的乳腺癌发生率显著高于Ib组和IIIa组，IVa组的发生率也高于Ia组。IVb组的发生率显著低于IVa组。IIIb组的癌为可触及的乳头管状腺癌，IVa组的为分泌性微腺癌。这些结果表明，卵巢切除和/或高剂量雌激素可完全抑制DMBA诱导的乳腺癌，但在存在适当水平雌激素的激素条件下，DMBA可引发乳腺癌。它们还表明，额外注射P可加速III组大鼠中DMBA诱导的乳腺癌生长，而额外注射P可抑制IV组大鼠中的乳腺癌生长。（摘要截短于250字）
