Metabolism of Progesterone in Uterine Tissue of Non-Pregnant Rats in Vitro

Abstract

The metabolism of labelled progesterone was studied in vitro in uterine tissue of non-pregnant rats with particular emphasis on the influence of substrate concentration. Neither a qualitative nor quantitative difference was found for a steroid tissue ratio between 15 \m=x\10\m=-\6and 4.2 \m=x\10\m=-\9 to 1 g (substrate amounts between 57.73 and 0.02 nmol); with both concentrations 42 to 44 per cent of progesterone was metabolized to about 35 per cent monohydroxymonoketonic steroids and 4\p=n-\6 per cent dihydroxylated C21O2-compounds.In both sets of incubations we have isolated and identified the following steroids: 3\g=a\-hydroxy-5\g=a\-pregnan-20-one,3\g=b\-hydroxy-4-pregnen-20-one, 3\g=a\-hydroxy-4-pregnen-20-one,20\g=a\-hydroxy-4-pregnen-3-one,5\g=a\-pregnane-3\g=a\,20\g=a\-dioland 4-pregnene-3\g=a\,20\g=a\-diol. The most abundant metabolite formed in these incubations was 3\g=a\-hydroxy-4-pregnen-20-one \ x =r eq-\ which corresponds to about 30 per cent of the total activity recovered. It is the first time that the presence of 20\g=a\-hydroxysteroid-oxidoreductase activity is definitely established in this type of tissue. The identification of three allylic alcohols as progesterone metabolites in the rat uterus confirms that \g=D\4-3-hydroxysteroids are important intermediates in the in vitro uterine metabolism of steroids.

Sperm acrosome antigen-1

“…Similar to the pharmacologic group of benzodiazepines, which also act on the GABA A receptor complex, these steroids have anesthetic effects (Stephenson et al 1986). The metabolites can also be produced within the female genital tract and ovary of mammals in vitro (Lerner and Eckstein 1976;Lisboa and Holtermann 1976). Sperm also appear to possess steroidogenic potential (Nagahama 1987).…”

METABOLISM OF 20β-Hydroxy-4-Pregnen-3-One IN UTERINE TISSUE OF NON-PREGNANT RATS IN VITRO

“…In essence, the chemicals used were the same as in the investigation carried out with progesterone (Lisboa Se Holtermann 1976 (pH 5.5) and incubated with 200 pg oi crystalline enzyme (0.2 ml of a 10 % solution in phosphate-buffer, pH 5.5), and 2.128 mg NADH for 2 h at 37°C in air. After addi¬ tion of 3 ml water the incubation medium was purified on a 1.1 x 16.5 cm Amberlite XAD-2 column, which was washed with 5 ml methanol-water 1:9 (v/v).…”

“…Radio gas chromatography (RGC) was performed on a Pye gas Chromatograph, model 104 (Pye-Unicam, England) associated with the detector assembly manufactured by Panax Equipment (England) as described by Lisboa Se Holtermann (1976). A radioactive peak is eluted ahead from the corresponding FID-peak by technical reasons; the difference between both peaks, which increase with the speed of the paper in the recorder is determined with standards for the experimental conditions used.…”

“…The incubation medium was purified on Amberlite XAD-2 column as described in a precedent paper (Lisboa Se Holtermann 1976).…”