Isolation of differentially expressed aldose reductase in ovaries after estrogen withdrawal from hypophysectomized diethylstilbestrol treated rats: increased expression during apoptosis

More than 99% of the follicles are eliminated by apoptosis before reaching ovulation. Several growth factors and hormones inhibit apoptosis in the ova ry, including estrogen. Using differential display of mRNA, aldose reductas e was shown to increase in the ovary of diethylstilbestrol treated hypophys ectomized rats after estrogen withdrawal, inducing apoptosis. The aldose re ductase mRNA expression was confirmed to be 2.2 +/- 0.2-fold higher after e strogen withdrawal using northern blot analysis. In addition, untreated imm ature rats showed a 1.7 +/- 0.3-fold higher expression of ovarian aldose re ductase mRNA compared to ovaries 24 h after pregnant mare's serum gonadotro pin treatment, decreasing apoptosis in the ovary. In the prostate, the leve l of aldose reductase was increased 3.1 +/- 1.1-fold 2 days after castratio n induced apoptosis. Although the physiological role of aldose reductase in the ovary is not known, these data suggest that aldose reductase may be pa rt of a hormonally regulated apoptotic pathway in the ovary and prostate. ( C) 2000 Elsevier Science Ireland Ltd. All rights reserved.