Bengtsson M, Reinholt F P, Rydström J
Department of Biochemistry, Wallenberg Laboratory, University of Stockholm, Sweden.
Toxicology. 1992;71(3):203-22. doi: 10.1016/0300-483x(92)90024-9.
To identify the ovarian cell type(s) responsible for the metabolism of 7,12-dimethylbenz[a]anthracene (DMBA) and their dependence on hormonal influences, DMBA mono-oxygenase activity was determined in primary cultures of cells dispersed from rat ovaries and separated by centrifugation on discontinuous Percoll density gradients. The contents of progesterone and oestradiol in the different cell cultures were characterized. Moreover, the morphological appearance of ovarian cells obtained from untreated and pregnant mare's serum gonadotropin (PMSG)-treated rats was examined. It is concluded from experiments with immature PMSG-treated rats, that DMBA mono-oxygenase activity is localized in follicular granulosa (and/or theca) cells. This activity decreases during luteinization, and is recovered in a population of cells harvested at a higher density on the Percoll gradient. The xenobiotic-metabolizing activity was not correlated to the rate of biosynthesis of progesterone or oestradiol in isolated cells, measured in the presence or absence of human chorionic gonadotropin and/or testosterone. However, a certain dependence of DMBA metabolism on steroids and/or steroid-synthesizing enzymes could not be excluded. For example, DMBA mono-oxygenase activity was markedly increased in a cell population, tentatively identified as granulosa cells, obtained from untreated mature rat ovaries upon addition of testosterone, which is the substrate for oestrogen synthesis, to the cell culture.
为了确定负责7,12-二甲基苯并[a]蒽（DMBA）代谢的卵巢细胞类型及其对激素影响的依赖性，在从大鼠卵巢分散并通过在不连续Percoll密度梯度上离心分离的细胞原代培养物中测定了DMBA单加氧酶活性。对不同细胞培养物中孕酮和雌二醇的含量进行了表征。此外，还检查了从未经处理和经孕马血清促性腺激素（PMSG）处理的大鼠获得的卵巢细胞的形态外观。从未成熟PMSG处理的大鼠的实验得出结论，DMBA单加氧酶活性定位于卵泡颗粒（和/或卵泡膜）细胞中。这种活性在黄体化过程中降低，并在Percoll梯度上以更高密度收获的细胞群体中恢复。在存在或不存在人绒毛膜促性腺激素和/或睾酮的情况下测量，异生物质代谢活性与分离细胞中孕酮或雌二醇的生物合成速率无关。然而，不能排除DMBA代谢对类固醇和/或类固醇合成酶的某种依赖性。例如，在细胞培养物中加入作为雌激素合成底物的睾酮后，从未经处理的成熟大鼠卵巢获得的、初步鉴定为颗粒细胞的细胞群体中，DMBA单加氧酶活性显著增加。
