Estradiol-stimulated increases in uterine eosinophils and nuclear type II estrogen-binding sites are prevented by pertussis toxin

Presence of uterine peroxidase activity in the rat early pregnancy

Peroxidase has been associated with estrogen action in the uterus. This enzyme plays an important role in the control of hydrogen peroxide levels and in catechol estrogen production. Since the uterus, during early pregnancy, is subjected to estrogen and progesterone regulation, we analyzed the changes of peroxidase activity in relation to receptivity and uterine early response to the embryo. Soluble and microsomal peroxidase activity were determined in the rat uterus during the estrus phase and early pregnancy (days 3 through 6). Soluble peroxidase activity increased significantly (p < 0.01) from day 3 (1.50 +/- 0.24) to day 4 (3.5 +/- 0.3) and 5 (5 +/- 0.5 U/mg protein, mean +/- S.D., n = 6) of pregnancy. During day 6, a significant decrease was noted in both the implantation site and the nonimplantation uterine tissue. Microsomal calcium-extractable peroxidase showed a similar pattern, with lower specific activity than, the soluble peroxidase. During estrus, the uterine tissue showed the highest activity of calcium-extracted peroxidase (8.7 +/- 1.35 U/mg protein), statistically greater when compared with days 3, 4, 5 and 6 of pregnancy. In conclusion, high peroxidase activity was associated with uterine receptivity. The decrease of activity on day 6 might be due to a progesterone-estrogen interaction, and consequently, hydrogen peroxide can be utilized for hydroxile production by means of the Fenton reaction. Lipoperoxidation may be necessary for changes in membrane fluidity for embryo attachment to endometrial epithelium.

The hamster cheek pouch as a convenient ectopic site for studies of uterine morphogenesis and endocrine responsiveness

The Syrian hamster cheek pouch was evaluated as a convenient transplantation site for studies of estrogen-dependent uterine growth and morphogenesis. At one month of age, hosts were either ovariectomized (Ovex) or ovariectomized and estrogen implanted (Ovex+E2), and at the same time the uterus from a 7-day old untreated donor was transplanted into the host's right cheek pouch. Periodic inspection (by simple eversion of the pouch) revealed viable transplants in the majority of hosts for both groups, and clear evidence of estrogen-dependent transplant growth that continued for at least 9 months. At that time, weight of the transplanted uterus was comparable to that of a given host's own in situ uterus, but uteri at both sites weighed six to eightfold more in Ovex+E2 hosts than in Ovex hosts. Histological analysis also revealed similar degrees of endometrial atrophy in Ovex hosts and hypertrophy/hyperplasia in Ovex+E2 hosts for both in situ and transplanted uteri. Furthermore, while only scant and rudimentary endometrial glands developed in both in situ and transplanted uteri within Ovex hosts, uteri at both sites within the Ovex+E2 hosts were riddled with cystic glandular structures and exhibited marked leukocytic infiltration. These data demonstrate that neonatal uteri transplanted to the hamster cheek pouch will grow, differentiate and follow an endocrine-responsive morphogenetic program that is quantitatively and qualitatively consistent with that of the host's in situ uterus. Lastly, we were able to cleanly separate epithelium from the stroma of 5-day old hamster uteri, reassociate the two tissues in vitro, transplant the recombinants into cheek pouches of adult female hamsters and subsequently observe growth and maintenance of a generally normal uterine morphology and differentiated function.

Capacity of adipose tissue to promote growth and metastasis of a murine mammary carcinoma: effect of estrogen and progesterone

Previously we have shown that a murine mammary carcinoma cell line, designated SPI, grows and metastasizes more efficiently in the mammary gland than in the subcutis. In this report, we examine the tissue specificity of this phenomenon. Our results show that SPI cells grow best in the mesenteric and ovarian fat pads and well in the mammary gland, but very poorly in the subcutis or peritoneal cavity. Massive dissemination of tumors from the ovarian and mesenteric sites occurs to the liver, spleen and diaphragm. In contrast, metastases from the mammary site occur primarily in the lung. Co-transplantation of a threshold number of SPI cells with mammary or ovarian fat fragments into the subcutis results in increased tumor growth, whereas very few tumors form in sham controls receiving no fat fragments. Removal of the ovaries of donor and recipient mice abrogates tumor growth in adipose tissue transplants. Estrogen can stimulate growth of SPI in adipose tissue sites, whereas progesterone inhibits growth. In contrast, in vivo growth of a stable metastatic variant selected from SPI cells was not inhibited by progesterone. SPI cells growing in ovarian and mesenteric fat pads showed increased expression of estrogen receptors and progesterone receptors, as well as detectable levels of epidermal-growth-factor receptors, whereas receptor levels decreased to baseline on tumors in the subcutis. The levels of estrogen-receptor mRNA reflect the corresponding functional expression of receptors; this finding suggests that the regulation of estrogen-receptor expression in this system is, at least in part, at the mRNA level. Our results are consistent with the model that adipose tissue exerts an estrogen-dependent positive regulatory effect on primary SPI tumor growth, and promotes the formation of metastases.

Preliminary characterization and partial purification of rat uterine nuclear type II Binding sites

These studies represent the first biochemical characterization and purification of nuclear type II binding sites from the rat uterus. Uterine nuclei from estradiol-implanted rats were digested with DNA'se and RNA'se, washed with Na deoxycholate-Tween 40 and extracted with 0.4 M ammonium sulfate (AmSO4). Nuclear type II sites in the AmSO4 extract eluted as a single peak during DEAE ion exchange chromatography, HPLC (Waters DEAE 5PW column) and Sephadex G-100 chromatography with a molecular weight of approximately 37K. DEAE and quercetin-sepharose affinity chromatography resulted in significant purification (greater than 800-fold) of nuclear type II sites with a 49% yield. Type II sites were not recognized by rat ER antibodies (Abbot ER-EIA kit) which immunoadsorbed ER from these preparations. These biochemical and immunological studies suggest that the ER and type II sites are likely to be different proteins.