A comparison of steroid hormone concentrations in human tissues including breast cancer.

Abstract

STUDIES with human tissue slices in vitro (Braunsberg and James, 1967a) showed that many tissues are capable of binding steroid hormones. Muscle bound relatively little, while adipose tissue showed the largest uptakes of testosterone, oestradiol and progesterone from saline solution. One of ten malignant tumour samples studied took up a relatively large amount of testosterone, but this did not exceed the uptake by adipose tissue. During incubation in serum albumin solution or plasma, little or no steroid was taken up by the tissues studied.The present investigation was undertaken in order to assess whether in vitro equilibration studies can yield meaningful results in relation to tissue hormone concentrations in vivo and to compare the distribution of androgen and oestrogen in human tissues with particular reference to malignant breast tumours. To this end, patients with-or suspected of having-breast cancer were given constant infusions of tracer doses of tritium-labelled testosterone or oestradiol in an attempt to reach radioactive equilibrium in the whole body. Under these conditions, the concentrations of free steroid tritium in the tissues are proportional to those of the endogenous hormone and its metabolites. A comparison of individual tissue concentrations in each patient is, therefore, possible. Even when equilibration is incomplete, gross differences in concentrations may be detectable (Braunsberg and James, 1967b). MATERIALS AND METHODSReagent8.-Petroleum ether (60°-80°) and methylene chloride (both general purpose reagents) were purified as described for hydrocarbons by Bush (1961), except that they were dried over anhydrous sodium sulphate before distillation. Ethanol (Distillers' Company Ltd.) was purified as described for methanol by Bush (1961). Methanol was redistilled and water was glass-distilled. Ether was washed with A volume of saturated aqueous ferrous sulphate acidified with hydrochloric acid, followed by water until neutral. It was then dried over anhydrous sodium sulphate and redistilled through a Dufton column. The liquid scintillator was prepared as described in another paper (Braunsberg and James, 1967a).Testosterone-4-14C (101 #tCi/mg.), uCi/mg.) and oestradiol-6,7-3H (120 #aCi/,ag.) were from the Radiochemical Centre, Amersham, Bucks.Testosterone-1,2-3H (135 ,tCi/,tg.) was kindly provided by the Endocrinology Study Section, National Institutes of Health, Bethesda, Md. The tritium-labelled steroids were stored as dilute solutions (4 to 8 ,uCi/ml.) in dry benzene at -15°C. and were checked for purity by paper chromatography before use and after completion of the last infusion.

Observations on the binding of testosterone to malignant mammary tumours and other tissues in vitro.

“…Analysis of tissue radioactivity after constant infusions of the labelled material in vivo provides a more convenient basis of comparison with in vitro equilibration experiments (Braunsberg and James, 1967). Such a study with labelled testosterone (Braunsberg, Irvine and James, 1967), like the in vitro studies reported here, failed to reveal any marked specific uptake of radioactivity by breast tumour tissue. The in vitro uptake of adipose tissue in relation to that of muscle appears to be rather higher than that in vivo.…”

“…A sample of adipose tissue incubated with testosterone in the patient's plasma gave a ratio of 2-2. Quantitative comparisons between in vitro equilibration and single injection of the labelled substance in vivo (Stone andBaggett, 1965, 1966) are complex and would require careful mathematical analysis (Braunsberg and James, 1967). Analysis of tissue radioactivity after constant infusions of the labelled material in vivo provides a more convenient basis of comparison with in vitro equilibration experiments (Braunsberg and James, 1967).…”

“…Quantitative comparisons between in vitro equilibration and single injection of the labelled substance in vivo (Stone andBaggett, 1965, 1966) are complex and would require careful mathematical analysis (Braunsberg and James, 1967). Analysis of tissue radioactivity after constant infusions of the labelled material in vivo provides a more convenient basis of comparison with in vitro equilibration experiments (Braunsberg and James, 1967). Such a study with labelled testosterone (Braunsberg, Irvine and James, 1967), like the in vitro studies reported here, failed to reveal any marked specific uptake of radioactivity by breast tumour tissue.…”

“…It implies free entry of hormones into the tumour, and this has been demonstrated in human subjects following injections of testosterone (Ellis, Parker, Bulbrook and Deshpande, 1965), steroid oestrogens (Davis, Wiener, Jacobson and Jensen, 1963;Demetriou, Crowley, Kushinsky, Donovan, Kotin and MacDonald, 1964), and progesterone (Deshpande and Belzer, 1966). The results of these single-injection experiments also suggested the existence of kinetic differences in steroid turnover in various tissues, which could arise from differences in tissue steroid concentrations, or in the rates at which these substances can enter and leave the tissues, or both (Braunsberg and James, 1967). The information currently available on tissue concentrations of steroid hormones is extremely limited because of the considerable technical difficulty of estimating quantitatively the small amounts which are present.…”

“…Both these approaches have been investigated in relation to the problem of human breast tumours. In this paper, the results obtained with an in vitro technique are presented; the in vivo studies are reported elsewhere (Braunsberg, Irvine and James, 1967).…”