The distribution of α inhibin and α glutathione S-transferase (δ4–5 isomerase) in the ovaries of patients with endometrial carcinoma

Abstract. Tiltman AJ, Allard U. The distribution of α inhibin and α glutathione S-transferase (δ^4–5 isomerase) in the ovaries of patients with endometrial carcinoma.
Estrogen is to thought to play a role in the pathogenesis of low grade but not high grade endometrial carcinomas. The dominant circulating estrogen in post menopausal women is estrone which is formed by aromatization of androstenedione. δ^4–5 isomerase, active in the conversion of dehydroepiandrosterone to androstenedione, may be demonstrated immunohistochemically by the antibody to α glutathione S-transferase (αGST). Inhibin, normally acting to suppress FSH secretion, also has an LH-dependent paracrine stimulatory effect on ovarian stromal cells to produce androstenedione. The purpose of this study was to compare the distributions of αGST and α inhibin in the ovaries of patients with low grade and high grade endometrial carcinomas. The results show a statistically significant increase in intracytoplasmic αGST staining in patients with low grade endometrioid adenocarcinomas compared to high grade carcinomas. There was also a statistically significant correlation between the distribution of αGST and α inhibin. These findings lend some support to the hypothesis that estrogen plays a role in the pathogenesis of low grade carcinomas; that the increase in estrone is partly due to increased production of androstenedione by the ovary and that this increased production could be the consequence of increased inhibin paracrine activity.