Quantitative analysis of 11-dehydrocorticosterone and corticosterone for preclinical studies by liquid chromatography/triple quadrupole mass spectrometry

Corticosteroid-binding Globulin (SERPINA6) Establishes Postpubertal Sex Differences in Rat Adrenal Development

Encoded by SerpinA6, plasma corticosteroid-binding globulin (CBG) transports glucocorticoids and regulates their access to cells. We determined how CBG influences plasma corticosterone and adrenal development in rats during the pubertal to adult transition using CRISPR/cas9 to disrupt SerpinA6 gene expression. In the absence of CBG, total plasma corticosterone levels were ∼80% lower in adult rats of both sexes, with a greater absolute reduction in females than in males. Notably, free corticosterone and adrenocorticotropic hormone were comparable between all groups. Between 30 and 90 days of age, wild-type female rats showed increases in adrenal weight and the size of the corticosterone-producing region, the zona fasciculata (zf), in tandem with increases in plasma CBG and corticosterone concentrations, whereas no such changes were observed in males. This sex difference was lost in rats without CBG, such that adrenal growth and zf expansion were similar between sexes. The sex-specific effects of CBG on adrenal morphology were accompanied by remarkable changes in gene expression: ∼40% of the adrenal transcriptome was altered in females lacking CBG, whereas almost no effect was seen in males. Over half of the adrenal genes that normally exhibit sexually dimorphic expression after puberty were similarly expressed in males and females without CBG, including those responsible for cholesterol biosynthesis and mobilization, steroidogenesis, and growth. Rat adrenal SerpinA6 transcript levels were very low or undetectable. Thus, sex differences in adrenal growth, morphology and gene expression profiles that emerge during puberty in rats are dependent on concomitant increases in plasma CBG produced by the liver.

Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) as an Alternative to Gas Chromatography/Mass Spectrometry (GC/MS) for the Analysis of Cyclohexanone and Cyclohexanol in Plasma

Self-poisoning with professional agricultural pesticide products is responsible for about 20% of global suicide, with most cases occurring in South Asia and China. Treatment of severe poisoning involves long-term intensive clinical care and is often unsuccessful. Solvent co-formulants (such as cyclohexanone) also contribute to mortality themselves or via more toxic metabolic products (such as cyclohexanol). Faster detection of co-formulants could aid earlier identification of pesticide poisoning and faster intervention, reducing mortality. Conventional analysis of volatiles in blood uses headspace (HS)-GC/MS. This paper evaluates SIFT-MS, a direct MS technique that provides higher sample throughput than GC/MS, as a potential tool for cyclohexanone and cyclohexanol analysis in plasma. Both instruments were calibrated using a conventional approach prior to analysis of each porcine plasma sample on both instruments. Comparative data were evaluated using Bland-Altman plots, demonstrating that the techniques were in good agreement. Compared with GC/MS, SIFT-MS provides fourfold higher sample throughput and shows great promise as an alternative analytical tool.