EVALUATION BY GAS CHROMATOGRAPHY OF THE URINARY STEROIDS OF THE PREGNANT DAIRY COW

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Abstract
SUMMARY: The ketonic and non-ketonic neutral steroids from the urine of pregnant dairy cows were examined by gas chromatography. The free and acetylated metabolites were chromatographed on QF-1, the trimethylsilyl ethers on NPGA, and the oxidized material on QF-1, SE-30 and NPGA. As an aid to structural identifications, the elution ranges for various groups of metabolites were calculated for steroid alcohols and acetates on QF-1, and for trimethylsilyl ethers on NPGA. Epiandrosterone, aetiocholanolone and androsterone were the most abundant metabolites in the ketonic fraction, their combined concentration in the urine being of the order of 0·6 mg./l. Minor metabolites in the ketonic fraction included 5α- and 5β-androstanedione, 5β-pregnanedione and 3α-hydroxy-5β-pregnan-2-one. The non-ketonic fraction contained 5β-androstane-3α,17α-diol and 5α-androstane3β,17α-diol. In addition, evidence was obtained for the presence of a number of pregnanediols in this fraction, of which 5β-pregnane-3α,20α-diol was identified with certainty. The possibility of estimating this diol quantitatively by means of gas chromatography has been examined.