The Use of Nonradiolabelled Steroid Infusions to Investigate the Origin of Oestrone Sulphate in Postmenopausal Women

Summary

Infusion of nonradiolabelled dehydroepiandrosterone sulphate (DHA-S) has been used to investigate the possible formation of oestrone sulphate via a sulpha ted conjugate of androstenedione. The metabolic clearance rate (MCR) of DHA-S also was measured and the mean value (25 1/24h) was similar to values reported using isotopic techniques. Although conversion of DHA-S to 5-androstenediol, a steroid with oestrogenic properties, was detected during infusion of DHA-S, there were no significant increases in plasma levels of conjugated androstenedione or oestrone sulphate. The MCR's oestrone sulphate measured using infusion of non-radiolabelled steroid in two menopausal women were 99 1/24h and 121 1/24h. For one woman, the production rate of oestrone sulphate, calculated from the conversion of oestrone and oestradiol to oestrone sulphate (151 nmol/ day) was similar to the measured production rate of oestrone sulphate (144 nmol/day). It is concluded that in menopausal women, oestrone sulphate is derived from conversion of oestrone and oestradiol with no formation occurring via conjugated androstenedione.

Key-Words

Oestrone Sulphate - Dehydroepiandrosterone Sulphate - Oestrone - Metabolic Clearance Rate - Transfer Constant