Walter G. Wiest

Progesterone withdrawal during hypertonic saline-induced abortions☆

Abstract In the present collaborative study, 4 independent investigators analyzed 24 samples of plasma from 6 normal obstetric patients. Careful exchange of amniotic fluid with 20 per cent NaCl predictably provoked evolution of uterine activity and abortion. This occurrence has been explained by an induced, partial, progesterone withdrawal.

Further studies of rat ovarian 20α-hydroxysteroid dehydrogenase

Abstract Rat Ovarian 20α-hydroxysteroid dehydrogenase has been purified 25 fold by fractional ammonium sulfate precipitation and DEAE-cellulose chromatography. The pH optimum for reduction of the 20-ketone is between pH 5.6 and 6, the optimum for oxidation of the 20α-hydroxyl between pH 8 and 9. Kinetic constants for a number of steroid substrates were measured. Steroids with a 5β-pregnane nucleus are good substrates while those with a 5β-pregnane nucleus react less well. It was concluded that a planar α-face of the steroid ring is not necessary for reactivity. 20β-Hydroxypregn-4-en-3-one, 17β-hydroxy-androst-4-en-3-one and 21-hydroxypregn-4-en-3-one are competitive inhibitors of 20α-hydroxysteroid oxidation.

Induction of rat ovarian 20α-hydroxysteroid dehydrogenase activity by gonadotrophic hormone administration

Abstract The increased activity of rat ovarian 20α-hydroxysteroid dehydrogenase observed during proestrus and estrus results in an increased secretion of the biologically weaker or impotent steroid, 20α-hydroxypregn-4-en-3-one, from the gland. The decreased activity of this enzyme during pseudopregnancy allows the progestational potency of the ovarian secretion to rise commensurate with the need. The present study, performed on hypophysectomized prepubertal female rats, was designed to study gonadotrophic hormone action responsible for regulation of 200-hydroxysteroid dehydrogenase and glucose-6-P dehydrogenase activities. Both enzyme activities correlate positively with the process of interstitial cell and thecal cell luteinization achieved either by HCG administration or by simultaneous administration of FSH and LH. Levels of glucose6-P debydrogenase normally present in immature or adult rats are in excess of those required for estrogen biogenesis.

Stoffwechsel von Progesteron-4-C14 im Arrhenoblastom

SummaryVirilizing arrhenoblastoma obtained from a 20-year-old woman has been incubatedin vitro with progesterone-4-C14. Conversion to 17 α-hydroxy-progesterone, Δ4-androstene-3,17-dione, and at least two more polar substances has been demonstrated.