Mass spectrometric and mass fragmentographic determination of natural and synthetic steroids in biological fluids.

One of the most significant advances in steroid methodology in the last decade has been the development of gas chromatograph-mass spectrometric (GC-MS) procedures. In this report a series of methods for steroid determination and detection, in which an LKB 9000 gas chromatograph-mass spectrometer linked to a Hewlett-Packard minicomputer (HP 2100A) or a Varian MAT CH7 with the data system Spectrosystem 100 MS has been used, are described. A mass fragmentographic (MF) method for the determination of 11 estrogens in various biological fluids is outlined. The levels of these steroids in late pregnancy plasma pools and in male and female bile are discussed. A method for the determination of unconjugated estriol in pregnancy plasma, for use in the monitoring of fetal well-being, and a second, for measuring unconjugated and conjugated estriol in nonpregnancy plasma are described. The latter method has been used in a pharmacological study of the luteolytic effects of administered estriol in humans. After the administration of single oral doses of megestrol acetate (MA) plasma levels were monitored by both m.f. and radioimmunoassay (RIA). The better specificity of the m.f. method unmasks interference by other compounds, probably metabolites, with the RIA. Studies on the mass spectrometrical characteristics of human urinary MA metabolites are also described.The use of m.f. facilitated the measurement of conjugated 17-ketosteroids in small portal venous plasma pools from postmenopausal women. Their concentrations are compared to those in a peripheral pool from the same subjects.