Characterization of a glucocorticoid receptor in neonatal rat mammary gland.

A glucocorticoid receptor has been identified in cytosolic fractions prepared from 4-day old female Sprague-Dawley rat mammary glands at an early resting stage of mammary development. This component sedimented at 10S and 5S on respectively low and high (0.4 M KCl) ionic strength gradients. It bound dexamethasone with a high affinity (Kd approximately 2-6 nM) and a low capacity (N = 300 +/- 100 fmol per mg of proteins or 3.3 +/- 1.3 fmol per micrograms DNA), with a hierarchy of affinity by competition studies dexamethasone greater than corticosterone greater than progesterone greater than R 5020 much greater than Estradiol-17 beta. The characteristics of this glucocorticoid-binding protein are thus very similar to the adult one isolated from adult rat mammary gland.

Estrone and dehydroepiandrosterone sulfatase activities and plasma estrone sulfate levels in human breast carcinoma.

The activity of the two membrane-bound sulfatases, estrone and dehydroepiandrosterone sulfatases, are reported in human breast carcinoma tissues. In 21 tested tumors (12 from post-menopausal women and 9 from nonmenopausal women), the two sulfatases were consistently present. The apparent Km values for estrone and dehydroepiandrosterone sulfatases were, respectively, 6.8 and 14.9 microM. In terms of maximal velocity, the sulfatase activities are not correlated to the estrogen or progesterone receptor status of the tumors or to the hormonal status of the donors. It may be concluded that these two activities are not hormone dependent. Estrone sulfate, the substrate of estrone sulfatase, has been measured in plasma of postmenopausal women. The mean levels (nmol/liter) of plasma estrone sulfate were compared in post-menopausal women with (n = 51) or without (n = 39) breast cancer. For the first age group (48 to 55 years old), no statistically significant difference in these levels was observed [1.91 +/- 1.06 versus 1.50 +/- 1.04 (mean +/- t0.95 (Formula: see text) S.E.)]. For the two other age groups (56 to 65 and 66 to 80 years of age), the differences were statistically significant [1.46 +/- 0.43 versus 0.77 +/- 0.21 (p less than 0.02) and 1.77 +/- 0.53 versus 0.81 +/- 0.22 (p less than 0.01)]. The usefulness of plasma estrone 3-sulfate levels as an indicator of the real estrogen status of postmenopausal women is discussed.