An in-house radioimmunoassay (RIA) for the measurement of androstenedione levels in serum was established and validated. Levels of androstenedione were measured by RIA using serum samples from various normal population groups and patients with congenital adrenal hyperplasia (CAH). Analytical recovery and linearity results were > 95%, while intra- and inter-assay CVs were < 10% and < 22% respect...

BACKGROUND Recently, LC-MS/MS was stated to be the method of choice to measure sex steroids. Because information on the mutual agreement of LC-MS/MS methods is scarce, we compared 7 published LC-MS/MS methods for the simultaneous measurement of testosterone, androstenedione, and dehydroepiandrosterone (DHEA). METHODS We used 7 published LC-MS/MS methods to analyze in duplicate 55 random sampl...

In human adrenarche during childhood, the secretion of dehydroepiandrosterone (DHEA) from the adrenal gland increases due to its increased synthesis and/or decreased metabolism. DHEA is synthesized by 17α-hydroxylase/17,20-lyase, and is metabolized by 3β-hydroxysteroid dehydrogenase type 2 (3βHSD2). In this study, the inhibition of purified human 3βHSD2 by the adrenal steroids, androstenedione,...

Heifers were treated with saline (Group I, N = 10), keyhole limpet haemocyanin (KLH; Group II, N = 10), androstenedione-KLH antigen (Group III, N = 14), or oestradiol-17 beta-KLH antigen (Group IV, N = 14). Booster injections were given to produce binding of greater than 10% at dilutions of 1:100 to 1:1000 (50% binding = 14 X 4 pg androstenedione and 9 X 5 pg oestradiol). The heifers were mated...

The differential control of adrenal androgens and cortisol may be due to intra-adrenal factors, which may be age- or sex-related, or due to extra-adrenal factors, such as circulating hormones. The purpose of this study was to identify any intrinsic differences that may exist in steroidogenic production occurring within adrenals obtained from males and females, and any maturational differences t...

BACKGROUND Our objective was to investigate luteinizing hormone, follicle-stimulating hormone, testosterone, and androstenedione as predicitve markers for ovulation after laparoscopic ovarian drilling. METHODS We retrospectively analyzed 100 clompihen-resistant patients with the polycystic ovary syndrome who underwent laparoscopic ovarian drilling at our department. The main outcome measure w...

The plasma concentration, production rate, and conversion ratio of androstenedione and testosterone were studied in seven children with congenital adrenal hyperplasia (CAH) of the 21-hydroxylase type. Plasma androstenedione and testosterone measured by double isotope derivative assay and estimated blood production rates were manyfold increased in the untreated state, markedly suppressed with gl...

BACKGROUND The free androgen index (FAI) calculated using total testosterone measured by immunoassay does not correlate with oocyte fertilization rates; however, there is considerable cross-reactivity for testosterone with other androgens by immunoassay that is not found using isotope dilution liquid chromatography-tandem mass spectrometry (LC/MS/MS). AIMS This study was done to determine rel...

In human adrenarche during childhood, the secretion of dehydroepiandrosterone (DHEA) from the adrenal gland increases due to its increased synthesis and/or decreased metabolism. DHEA is synthesized by 17a-hydroxylase/17,20-lyase, and is metabolized by 3b-hydroxysteroid dehydrogenase type 2 (3bHSD2). In this study, the inhibition of purified human 3bHSD2 by the adrenal steroids, androstenedione,...

Several mammalian cytochrome P450 (P450) isoforms demonstrate homotropic cooperativity with a number of substrates, including steroids and polycyclic aromatic hydrocarbons. To identify structural factors contributing to steroid and polycyclic aromatic hydrocarbon binding to P450 enzymes and to determine the location of the allosteric site, we investigated interactions of the macrolide hydroxyla...