Rutteman G R, Misdorp W
Department of Clinical Science of Companion Animals, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands.
J Reprod Fertil Suppl. 1993;47:483-7.
Ovarian steroid hormones and their synthetic derivatives may enhance mammary tumorigenesis in dogs and cats. In toxicity studies of synthetic progestagens a dose-related effect has been observed in the dog, with low-dose exposure sometimes being protective against mammary tumour development. There is some evidence that steroid dependence, as reflected by the presence of steroid receptors (that are nearly always present in normal mammary tissue and benign mammary tumours), is decreased in advanced stages of malignant disease, both in the dog and cat. However, this difference in steroid receptor expression between benign and malignant conditions is not related to any significant alterations in the concentration of receptors for epidermal growth factor. Progestagens have been suggested to promote mammary tumorigenesis in the dog by their induction of growth hormone overproduction; however, there is no conclusive evidence that this effect is necessary for mammary tumour induction. Basal levels of growth hormone and of prolactin were found to be similar in tumour-bearing dogs and age-matched controls.
卵巢甾体激素及其合成衍生物可能会促进犬猫的乳腺肿瘤发生。在合成孕激素的毒性研究中，已在犬身上观察到剂量相关效应，低剂量暴露有时对乳腺肿瘤的发展具有保护作用。有证据表明，在恶性疾病的晚期，犬和猫体内甾体激素依赖性会降低，这表现为甾体激素受体（几乎总是存在于正常乳腺组织和良性乳腺肿瘤中）的存在。然而，良性和恶性状态下甾体激素受体表达的这种差异与表皮生长因子受体浓度的任何显著变化无关。有人提出孕激素通过诱导生长激素过度产生来促进犬的乳腺肿瘤发生；然而，没有确凿证据表明这种效应是诱导乳腺肿瘤所必需的。在患肿瘤的犬和年龄匹配的对照组中，生长激素和催乳素的基础水平相似。
