Quantification of neurosteroids during pregnancy using selective ion monitoring mass spectrometry

Abstract

Analytical techniques used to quantify neurosteroids in biological samples are often compromised by non-specificity and limited dynamic range which can result in erroneous results. A relatively rapid and inexpensive gas chromatography-mass spectrometry (GC-MS) was developed to simultaneously measure nine neurosteroids, including allopregnanolone, estradiol, and progesterone, as well as 25-hydroxy-vitamin D3 in plasma samples collected from adult women subjects during and after pregnancy. Sample preparation involved solid-phase extraction and derivatization, followed by automated injection on a GC equipped with a mass selective detector (MSD) operated in single ion monitoring (SIM) mode to yield a run time of less than 11 minutes. Method detection limits for all neurosteroids ranged from 30 to 200 pg/mL (parts per trillion), with coefficients of variation that ranged from 3 to 5% based on intra-assay comparisons run in triplicate. Although concentrations of estradiol measured by chemiluminescent immunoassay (CIA) were consistent with values determined by GC-MS values, CIA yielded considerable higher values of progesterone, suggesting antibody cross reactions resulting from low specificity. Mean neurosteroid levels and representative time-course data demonstrate the ability of the method to quantify changes in multiple neurosteroids during pregnancy, including rapid declines in neurosteroid levels associated with delivery. This simplified GC-MS method holds particular promise for research and clinical laboratories that require simultaneous quantification of multiple neurosteroids, but lack the resources and expertise to support advanced liquid chromatography-tandem mass spectrometry facilities.

Free and total plasma concentrations of elvitegravir/cobicistat during pregnancy and postpartum: a case report

“…This induction increases the metabolic clearance of both EVG and cobi, and consequently shortens the cobi‐boosting effect, thereby contributing to a lower EVG AUC 24 and C min . The modest change in EVG pharmacokinetics observed between pregnancy and postpartum, as also reported by others , is suggestive of a persisting induction of metabolism, as the effect of hormone‐induced changes might not have decreased to pre‐pregnancy levels . Of interest, EVG C min and f u were higher (149 ng ml –1 and 0.5%) when remeasured 6 months postpartum in this patient.…”

“…It requires pharmacokinetic boosting by the strong CYP3A4 inhibitor cobi to achieve adequate exposure over a dosing interval . Importantly, CYP3A4 and UGT1A1 are induced during pregnancy by female hormones such as progesterone, the level of which rises significantly and which has been shown to upregulate the hepatic expression of drug‐metabolizing enzymes through activation of the nuclear receptor PXR . This induction increases the metabolic clearance of both EVG and cobi, and consequently shortens the cobi‐boosting effect, thereby contributing to a lower EVG AUC 24 and C min .…”

Neurosteroid regulation of GABAA receptors: A role in catamenial epilepsy

“…A recent study has found that serum neurosteroid levels are reduced in patients in status epilepticus, which is a disorder characterized by self-sustaining seizures that can last for days to months (Meletti et al, 2017). Serum neurosteroid levels also increase as pregnancy progresses in women (Pennell et al, 2015). A similar measurement of serum neurosteroid levels in epilepsy patients could enhance our understanding of how spontaneous seizures affect endogenous neurosteroid synthesis.…”

Increased anxiety‐like phenotype in female guinea pigs following reduced neurosteroid exposure in utero

“…Finasteride blocks the conversion of all 5α‐reduced steroids, including 5α‐dihydrotestosterone and 5α‐dihydrodeoxycorticosterone and their GABA A R active metabolites (3α, 5α‐androstanediol and 3α, 5α‐tetrahydrodeoxycorticosterone, respectively). Although we cannot comment on the loss of these metabolites may be having on neurodevelopment and neural programming in late gestation of guinea pigs, given that allopregnanolone is the major circulating neurosteroid during pregnancy (Gilbert Evans et al, 2005; Pennell et al, 2015) and is the preferential product of pregnenolone and progesterone in animals and humans (Porcu et al, 2009) we suggest the behavioural changes found in juvenile female guinea pigs is due to the fetal programming of suppressed allopregnanolone production. We also cannot comment on what is occurring at the time of behavioural testing 21 days after birth in the animals in the current study, therefore the possibility that there are stress‐induced changes in brain allopregnanolone sensitivity leading to anxiogenic‐like behaviours in female guinea pigs cannot be excluded.…”