The steroids in meconium from normal male and female newborn infants have been studied by gas chromatography-mass spectrometry. Practically all steroids were excreted as monoand disulphates. The approximate concentrations of steroid mono-and disulphates were 430 and 470pg per g of meconium. Twenty unsaturated and fourteen saturated steroids were completely identified. Most of the unsaturated steroids had a 3/?-hydroxy-A6 structure. I n addition, seven saturated steroids were tentatively identified. No significant qualitative differences were found in the steroid composition of meconium from male and female newborns. The results are discussed in relation to present knowledge of steroid metabolism in the foeto-placental unit.Very little information is available on the excretion of neutral steroid metabolites in meconium from newborn infants. I n a series of publications Francis et al. . In order to obtain a complete understanding of the metabolism of neutral steroid hormones in the foeto-placental unit it was considered of interest to have a detailed knowledge of the metabolites excreted in meconium. New methods of purification in combination with gas chromatographymass spectrometry (for references see [6]) have now made it possible to separate and identify even minor constituents in small amounts of biological material. MATERIALS AND METHODS Collection of MeeoniumMeconium was collected from diapers not contaminated with urine. Samples from 6 male and 9 female infants were pooled to give a meconium pool from males (70 g) and a meconium pool from females (40 g). The samples were stored a t -20 "C until analysed. SteroidsThe sources of several of the steroids used as reference compounds were given in a previous Unusual Abbreviations. Progesterone, silyl, trimethylsilyl. The terms pregnanolone and pregnanediol are used as collective names for isomers of 3-hydroxy17p-pregnan-20-one and pregnane-3,2O-diol, respectively.Enzymes. 3-a-Hydroxysteroid : NADP oxidoreductase (EC 1.1.1.50).Note. Retention times, tg, are calculated relative to 5a-cholestane.paper [7]. 3~-Hydroxy-5-androsten-l7-one was purchased from Ikapharm (Ramat-Gan, Israel). 3/?,78-Dihydroxy-5-androsten-17-one and 3B,18-dihydroxy-5-androsten-17-one were gifts from Dr. G. Johannsson and Dr. C. H. L. Shackleton, respectively. 5-Androstene-3/?,17a-diol and 5m-androstane-3a,17a-diol were obtained from Schering AG (Berlin, Germany). 38-2 1 -Dihydroxy-5-pregnen-20 one-21 -acetate (purchased from Sigma Chemical Company, St. Louis, Missouri, U.S.A.) was hydrolysed with K2C0, in methanol a t room temperature over night. The resulting 38,21 -dihydroxy-5-pregnen-ZO-one was reduced with sodium borohydride in methanol and the following compounds were found : 5-pregnene-3@,20B, 21 -trio1 (high yield) and 5-pregnene-3B,20a,21 -trio1 (low yield). 3a-Hydroxy-5a-pregnan-ZO-one, 3m-hydroxy-5B-pregnan-ZO-one and 3B-hydroxy-5-pregnen-20-one were purchased from Ikapharm (Ramat-Gan, Israel). Sodium borohydride reductions of these compounds gave the corresponding 208-and 20a-hydr...

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The hepatic metabolism of 444-14C]androstene-3,17-dione and 5a[4-'4Cjandrostane-3a,17f3-diol was studied in castrated and hypophysectomized male rats with a transplanted pituitary under the kidney capsule. The effects of testosterone propionate and estradiol benzoate on liver metabolism were also studied in these experimental animals. It was found that the autonomous pituitary secreted a "feminizing factor" that transformed the male type of steroid metabolism characteristic of hypophysectomized rats into a female type of metabolism. Hypophysectomized rats were unresponsive towards androgen action on the liver and did not respond with feminized hepatic metabolism after treatment with estradiol benzoate. It is concluded {hat estrogenic action on liver enzymes is mediated via modulation of the secretion of a central (probably hypothalamic) "feminizing factor inhibiting factor" and that sex hormonal effects on hepatic metabolism only occur in the presence of a pituitary in situ. The metabolism of steroid hormones in rat liver shows large sexual differences (1-5). This differentiation of hepatic metabolism, which begins at about 4 weeks of age and is almost completed at about 8-10 weeks of age, is manifested due to active processes in both sexes (6-9). The female metabolic type is maintained by a pituitary factor, without gonadal influence, whereas the male metabolic type seems to be maintained by testicular androgens acting directly upon the liver in the presence of an intact pituitary (2, 10-13).The male type of hepatic metabolism is irreversibly determined or "programmed" at birth by testicular androgen (5,14,15); if castrated during the neonatal period, male rats develop a female type of metabolism when adult. In animals exposed to androgen at birth (i.e., normal males and androgenized females), the male type of hepatic metabolism is temporarily feminized after treatment with estrogen (5, 6). Castration of adult male rats leads to partial feminization of certain enzyme activities in the liver whereas other enzymes retain their male characteristics (5,12 Incubations. The animals were killed by cervical dislocation and the liver was excised and chilled to 0-+4'. From a 20% (wt/vol) homogenate in a modified Bucher medium (16), microsomal and soluble enzyme fractions were prepared by differential centrifugation (6). The microsomes were resuspended in the buffer. Cytosol from about 0.6 g and microsomal suspension from about 0.1 g of liver tissue were incubated at 370 in the presence of an NADPH-regenerating system (5) with 500 ,ug of 4-[4-'4C]androstene-3,17-dione (specific activity 0.49 ,uCi/mg). 5a-[4-'4C]Androstane-3a,17f3-diol (specific activity 3.0 ,uCi/mg), 200 ,ug, was incubated with microsomal suspension from about 0.5 g of liver tissue. The conditions of the incubations were designed to give conversions linear with time and enzyme concentration. Small changes in substrate and cofactor amounts did not affect the total conversion of substrate.The steroids were extracted from the incubation medium w...

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