Oestrogen receptors in transplantable ovary-independent, mammary tumours of the rat

Hawkins, R. A.; Hill, Adam T.; Freedman, B.; Killen, E.; Miller, William R.

doi:10.1016/0014-2964(78)90141-x

Cited by 7 publications

(15 citation statements)

References 16 publications

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“…It is known that not all DMBAinduced tumours are hormone-dependent and it might be postulated that the one such tumour in which no RP could be detected might have belonged to the hormone-independent minority of DMBAinduced tumours. This study revealed no overlap in RE levels between the two groups but it should be noted that in earlier generations of the TG3 and TG5 lines higher RE concentrations were found, and the distinction between the groups was less clear-cut (Hawkins et al, 1978;Scott et al, 1979).…”

contrasting

confidence: 47%

“…Previous work in our department has shown that over 80% of such tumours regress after oophorectomy (Hawkins et al, 1978;Scott et al, 1979). Twenty-four such tumours were examined in this study.…”

mentioning

confidence: 98%

“…Twenty-four such tumours were examined in this study. Two transplantable lines (TG3 and TG5) of rat mammary tumour which exhibit ovary-independent growth (Hawkins et al, 1978) have been generated in our department and 20 tumours of these lines were also examined.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Endogenous peroxidase: an alternative to oestrogen receptor in the management of breast cancer?

Penney¹,

Scott²,

Hawkins³

1980

Br J Cancer

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contrasting

confidence: 47%

mentioning

confidence: 98%

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Endogenous peroxidase: an alternative to oestrogen receptor in the management of breast cancer?

Penney¹,

Scott²,

Hawkins³

1980

Br J Cancer

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“…In the present study the growth of TG 5/4 and TG 5/7 tumours, though not influenced by ovarian ablation, appears to be stimulated by administration of oestrogen to oophorectomized animals. Although oestrogen-receptor activity was detectable in cytosols from TG 5/7 tumours (mean receptor level 3-4 fmol/mg protein, Kq 0 45 x 10-10M) the levels were much lower than in DMBA-induced hormone-dependent rat mammary tumours (Hawkins et al, 1978).…”

Section: Tumour Growthmentioning

confidence: 77%

Effects of serial passage on the endocrine response and steroid metabolism of a rat mammary carcinoma

Miller¹

1980

Br J Cancer

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“…However, the transplantable tumours were derived originally from DMBAinduced tumours, and at least one of the lines (TG5) was ovary-dependent in its first and second transplant generations. Since (1) oestrogen receptors are present in the tumours (Hawkins et al, 1978) and (2) tumour growth, whilst not ovarydependent, may be enhanced by oestradiol17fl administration (Figure), it seems likely that these tumours have retained some hormonal 8ensitivity during transplantation.…”

mentioning

confidence: 99%

Hormonal status and steroid metabolism in two transplantable rat mammary tumours

Miller¹,

Stewart²,

Hawkins³

1979

Br J Cancer

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HUMAN and rat mammary tumours metabolize steroid hormones and thus have the capacity to modify their local hormonal environment (Adams & Wong, 1968;Jones et al., 1970;King et al., 1964;Miller et al., 1974). In previous studies, we have investigated the metabolism of testosterone by a predominantly ovary-dependent DMBA-induced mammary tumour, and have shown it to be sensitive to levels of other hormones present in vitro (Miller, 1976a), or in vivo (Miller, 1976b, c;Buchan et al., 1976). We now report a study of the metabolism of androgens by ovary-independent tumours derived by transplantation. By using multiple tumours transplanted to a single rat, it has been possible to examine tumours derived from the same host animal before and after 2 endocrine manipulations.All animals were of an inbred strain of Sprague-Dawley rat, obtained from the Animal Diseases Research Association (ADRA), Moredun Institute, Edinburgh. Two lines of transplantable tumours were used: TG3 and TG5. These were histologically carcinomas, originally induced in female "ADRA" rats at 50 days of age by i.v. administration of 5 mg of DMBA. Both tumours were then serially transplanted by dorsal skin implantation of tumour fragments into neonatally-thymectomized hosts. At the time of study TG3 was at its 6th passage and TG5 was at its 7th passage.Three separate portions of a single donor tumour were implanted at different dorsal sites in each neonatally thymectomized host animal at 50 days of age. Tumours were measured twice weekly throughout the period of study. When the largest tumour reached 1 5 x 1 5 cm in size it was removed through a dorsal skin incision and the animal was immediately bilaterally oophorectomized. Ten days later, a further tumour was excised. The animals were then given daily injections of oestradiol-17f (1 jig in 0-2 ml corn oil) for a further 10 days.The remaining tumour was excised and the animals were killed, no injection of oestradiol being given on the day of death. Eight rats were so treated (4 with TG3 tumours and 4 with TG5 tumours). Control animals (2 with TG3 tumours and 2 with TG5 tumours) were treated similarly except that a sham oophorectomy was performed in place of an oophorectomy and the injection vehicle replaced oestradiol.After excision, portions of each tumour (0.5 g) were used for steroid-metabolism studies. Each was finally sliced at 0°C in Krebs-Ringer phosphate buffer pH 7-4 (5 ml). An NADPH-generating system and radioactive precursor(20(lCi of either 7a(3H) dehydroepiandrosterone (DHA) or 7a(3H) testosterone) was added. The incubation systems were shaken at 37°C in an atmosphere of 02 for 2 h (TG3 series) or 1 h (TG5 series on account of the high activity found in the tumour lines). The reaction was stopped by adding methanol to 80% v/v and the incubations stored at

show abstract

Oestrogen receptors in transplantable ovary-independent, mammary tumours of the rat

Cited by 7 publications

References 16 publications

Endogenous peroxidase: an alternative to oestrogen receptor in the management of breast cancer?

Endogenous peroxidase: an alternative to oestrogen receptor in the management of breast cancer?

Effects of serial passage on the endocrine response and steroid metabolism of a rat mammary carcinoma

Hormonal status and steroid metabolism in two transplantable rat mammary tumours

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