Steroids determination

Adrenocortical Steroids, Determination of Individual (Neher), 1, 127 Amino Aciduria (Bigwood, Crokaert, Schram, Soupart and Vis), 2, 201 Ammonia, Blood (Bessman), 2, 135 Ascorbic Acid in Man and Animals (Knox and Goswami), 4, 122 Automation (Marsh), 2, 201 Bile Pigments in Jaundice (Billing), 2, 268... 

Bll. Besch, P. K., Steroid determinations, inherent clinical and laboratory errors. J. Amer. Med. Tecknol. 23, 1-6 (1961). 

Phenothiazines may increase serum cholesterol, spinal fluid protein, and urinary urobilinogen levels decrease protein bound iodine yield false-positive urine bilirubin tests interfere with urinary ketone and steroid determinations. 

Drug/Lab test interactions Plasma corticosteroid levels may be increased. Urinary steroid determinations may be altered by amphetamines. 

In 1975 a BCR Clinical Chemistry Working Group was founded for the preparation and the distribution of reference materials in the clinical chemistry field. Due to the major problems encountered in the labs during steroid determinations, a project for the preparation of a matrix reference material was accepted. The task of the BCR Expert Group on Steroid Hormone Analysis consisted of the following points ... 

Chiroptical methods are widely used in the elucidation of the structure of steroid molecules [1-9]. Quantitative determination and control of the optical purity of drugs can also be solved by chiroptical methods, but they are rarely applied in pharmaceutical analysis. In pharmacopoeias, the only experimental measurements that are reported are optical rotations at the sodium D-line. These figures provide no specificity and relatively low analytical sensitivities. Nevertheless several papers have appeared in the literature where steroid determinations are based on the measurement of optical rotation [1,10-17]. The purpose of this chapter is to describe the applications of circular dichroism (CD) spectral measurements to the analysis of steroid molecules with particular emphasis to pharmaceutical preparations and drug forms. 

After pituitary irradiation, patients should be evaluated every six months with an FT4 and TSH measurement, sex steroid determination, and ACTH stimulation testing. 

Grol M, Stock W, Ebert C. FuHy automated steroid determination on the immuno-analyzer ES 300 Development and performance of a new direct highly sensitive enzyme immunoassay for serum estradiol. Clin Chem 1991 37 1027. 

Taieb J, Benattar C, Birr AS, Lindenbaum A. Limitations of steroid determination by direct immunoassay. Clin Chem 2002 48 583-5. 

From k values of steroids determined at different temperatures from eluent of various compositions the differential enthalpy of adsorption from solution (—AH) at small coverage for some eluent composition can be calculated from ... 

Hershberger, L.G., Shipley, E.G. and Meyer, R.K. (1953) Myotrophic activity of 19-nortestosterone and other steroids determined by modified levator ani muscle method. Proceedings of the Society for Experimental Biology and Medicine, 83, 175-180. 

It is for these reasons that van Kampen and Hoek (H8) have chosen not a single steroid determination, but a whole spectrum with a multi-... 

Whereas the primary objective of a great many GC plasma steroid determinations is to measure one or just a few compounds, modem GC permits determination of the entire profiles of substances. Novotny et al. [115] utilized glass capillary columns combined with sample preconcentration to develop multiple profiles of different steroid conjugates from 1-5 ml plasma samples. Capillary GC and mass-fragmentographic detection were used by Axelson and Sjbvall [256] to monitor selectively the profiles of 3-ketosteroids in plasma from women in different stages of pregnancy. 

Because of these considerations, the development of a method for steroid determination that gives low LODs, but requires no derivation and little or no sample preparation is highly desirable. One viable alternative for steroid analysis in physiological fluids was given by coupling the sensitivity of sensitized lanthanide fluorescence in micellar media with the selectivity of MLC [12]. The advantage of the method lies in its speed and simplicity, while LODs are in the low ng/mL range. 

The stereochemistry of the polar groups in a steroid determines the orientation of the molecule when it is adsorbed onto the celite surface and this allows the position of oxidation to be controlled (e.g. equation 4.28) [124, 126, 127]. Many other alcohols, diols and triols are selectively oxidised by silver carbonate on celite [128]. 

The combination of TLC separation with densitometric evaluation provides high efficiency, selectivity, and sensitivity, and makes these techniques comparable to other high-resolution chromatographic methods. For example, the remarkable advantages of in situ TLC compared to GLC and HPLC are that derivatization is not necessary any type of chemical reagent can be used to increase the selectivity and sensitivity of steroid determinations. Thus, compounds differing widely in polarity can be separated and determined. The main disadvantages of these techniques derive from their lower accuracy and precision, caused mainly by imperfections of the sample application process and characteristics of the sorbent layer. 

Cortisol production rate. This consists of measuring the specific activity of a cortisol metabolite after administration of isotopically labelled cortisol. It gives similar information to that given by a 24 hour 17-oxogenic steroid determination but is subject to less interference by other chromogens. 

This is a collective term for a group of corticosteroids which includes cortisol, cortisone, 11-deoxycortisol and their tetrahydro derivatives which are measured in plasma and urine by the Porter-Silber reaction. The term 17-hydroxysteroids is often used synonymously with 17-oxogenic steroids and to most intents and purposes they mean the same. However there is a subtle difference between the two in that 17-oxogenic steroids (determined by the Zimmermann reaction after reduction and oxidation) measures, in addition to the compounds mentioned above, cortol and cortolone. 

Fig. 5. Time course of the effect of 10 fjg LH/5 ml on cyclic AMP accumulation and steroidogenesis. The changes in cyclic AMP concentration are shown as broken lines and the rates of steroidogenesis by solid lines. The control values are shown as open circles and the values obtained from LH treated tissue as solid circles. The incubation conditions were the same as in Fi. 4 except that the cyclic AMP and steroid determinations were made at various times during the second incubation.

Over the last decade, steroid determination by immunoassays has faced... 

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