Estrogen and progesterone receptors in canine mammary tumors.

Research Project

Project/Area Number	60560330
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Applied veterinary science
Research Institution	University of Tokyo
Principal Investigator	SASAKI Nobuo Univ. Tokyo, Fac. Agriculture, Associate Professor., 農学部, 助教授 (60107414)
Co-Investigator(Kenkyū-buntansha)	NISHIMURA Ryohei Univ. Tokyo, Fac. Agriculture, Assistant Professor, 農学部, 助手 (80172708) OHASHI Fumihito Univ. Tokyo, Fac. Agriculture, Assistant Professor, 農学部, 助手 (10126013) TAKEUCHI Akira Univ. Tokyo, Fac. Agriculture, Professor, 農学部, 教授 (90011874)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥2,000,000 (Direct Cost: ¥2,000,000) Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	mammary tumor / mammary tissue / canine / estrogen receptor / progesterone receptor / cytosol / プロジェステロンレセプター
Research Abstract	Thirty-seven canine mammary tumors with various histologic types were determined their cytosol estrogen and progesterone receptors(ER, PR) by the dextran-coated charcoal method. Out of the tumors, 64.7% showed ER positive(binding sites were more than 2 fmol/mg protein). The mean binding sites and dissociation constant(Kd) were 8.8 fmol/mg protein and 1.17 x <10^(-9)> M respectively. PR was detected in 71.0% of tumors examined(more than 5 fmol/ mg protein). The mean binding sites and Kd were 24.3 fmol/mg protein and 2.15 x <10^(-9)> M. And 90% of ER positive specimens were PR positive. Histopathologically, 35.5% of tumors were benign and the rest were malignant. Also 75.7% were epithelial origin. In benign tumors, 76.9% were ER positive and 90.9% were PR positive. But in malignant tumors, only 58.3% and 60.9% showed ER and PR positive, respectively. These results were quite similar to the receptor data reported in human and dogs. This suggests that the endocrine therapy in human may als … More o be effective in canine mammary tumors. In the next experiment, the correlation of receptors between neoplastic and non-neoplastic mammary tissues was investigated. Furthermore, 14 normal mammary tissues from healthy female dogs with normal estrous cycles were examined for the presence of the receptors as a control. Histopathologic examination revealed that 4 of 15 tumor bearing mammary tissues examined were hyperplastic and that the rest were normal. There were no significant differences in ER contents between the tumor tissues and their surrounding tissues. On the contrary, PR contents in surrounding tissues were considerably lower than those in mammary tumor tissues. But the levels of ER and PR contents in the surrounding tissues were similar to those of normal mammary tissues from normal female dogs. From these results, the most significant difference in ER and PR between neoplastic and non-neoplastic mammary tissues was the content of PR. A prolonged administration of progesterone was reported to induce mammary tumors. Thus, it is suggested that progesterone as well as estrogen may play an important role in the etiology of neoplastic change in canine mammary tumors. Less