Augmentation of the Response of Mouse Uterine Epithelial Cells to Estradiol by Uterine Stroma

Abstract

The effect of estrogen on the in vitro growth of mouse uterine epithelial cells was assessed. Epithelial cells from the immature mouse uterus were successfully cultivated in a 1:1 mixture of Dulbecco's Modified Eagle's Medium and Ham's F-12 supplemented with insulin (5 micrograms/ml), transferrin (10 micrograms/ml), hydrocortisone (10(-7) M), BSA (2 mg/ml), and fetuin (1 mg/ml). Addition of 17 beta-estradiol in the range of 1-100 nM did not significantly change the total DNA content of the epithelial cells. A binding component of [3H]estradiol by cultured uterine cells was shown to be specific, saturable, and of high affinity. Kd values for specific binding by epithelial and stromal cells were 1.0-1.7 x 10(-10) M. Maximal specific binding was 0.74 and 2.3 fmol/micrograms DNA for epithelial and stromal cells, respectively. Treatment of epithelial and stromal cells for 4 days with 10 nM estradiol led to a 2- to 6-fold increase in progesterone receptor concentration. Treatment of epithelial and stromal cells in mixed culture for 4 days with 10 nM estradiol resulted in a significant increase in total DNA. That epithelial-stromal contact was critical for estradiol stimulation was shown by the fact that if the cell types were separated into two compartments which still allowed free media mixing, total DNA was not enhanced by estradiol. These observations are organized into a model for mitogenic action of estradiol that seems to reconcile observed disparities in the action of the hormone in vivo and in vitro.

Mini-review: estrogen action in the uterus and insulin-like growth factor-I

“…Early experiments showed that E2 could stimulate uterine endometrial cell proliferation after direct instillation into one uterine horn, with no response in the contra-lateral horn, thus indicating that estrogens acted directly on the uterus, and implying that other systemic hormones were dispensable [11]. In contrast, other studies found that isolated uterine endothelial cells cultured in vitro did not proliferate in response to added estrogens [12][13][14][15], thus showing the need for additional trophic factors. The critical observation explaining this conundrum demonstrated that ERs were not detected in uterine epithelium but rather were found in the adjacent stroma [16], and suggested that proliferation of endometrial epithelial cells might be stimulated through a paracrine mechanism by growth-promoting substances elaborated in stromal cells in response to E2 [12][13][14][15].…”

Stromal estrogen receptors mediate mitogenic effects of estradiol on uterine epithelium

“…However, when cultured UtE is recombined with uterine stroma (UtS) and grafted in vivo, E 2 again stimulated mitogenesis in UtE of these tissue recombinants (13). Furthermore, in cocultures of UtS and UtE, E 2 increased epithelial DNA content, an effect not observed with E 2 treatment of pure epithelial cultures (14). This further suggests that E 2 -induced epithelial mitogenesis is mediated indirectly via stroma.…”

In vitro culture of bovine egg fertilized either in vivo or in vitro

“…This is not the optimal time during the estrus cycle for uterine cell viability (Fortier et al, 1988) (Inaba et al, 1988 (Table II). About fifty percent of them were expanded after 8 days of culture, but none of them hatched (even after 11 days).…”