Effects of Anticonvulsants on Human P450c17 (17alpha-Hydroxylase/17,20 Lyase) and 3beta-Hydroxysteroid Dehydrogenase Type 2

Mitochondrial dysfunction results in enhanced adrenal androgen production in H295R cells

The role of mitochondria in steroidogenesis is well established. However, the specific effects of mitochondrial dysfunction on androgen synthesis are not fully understood. In this study, we investigate the effects of various mitochondrial and metabolic inhibitors in H295R adrenal cells and perform a comprehensive analysis of steroid and metabolite profiling. We report that mitochondrial complex I inhibition by rotenone shifts cells toward anaerobic metabolism with a concomitant hyperandrogenic phenotype characterized by rapid stimulation of dehydroepiandrosterone (DHEA, 2 h) and slower accumulation of androstenedione and testosterone (24 h). Screening of metabolic inhibitors confirmed DHEA stimulation, which included mitochondrial complex III and mitochondrial pyruvate carrier inhibition. Metabolomic studies revealed truncated tricarboxylic acid cycle with an inverse correlation between citric acid and DHEA production as a common metabolic marker of hyperandrogenic inhibitors. The current study sheds light on a direct interplay between energy metabolism and androgen biosynthesis that could be further explored to identify novel molecular targets for efficient treatment of androgen excess disorders.

Effects of treatment with clinically relevant valproate, carbamazepine, oxcarbazepine, topiramate, lamotrigine and levetiracetam on ovarian folliculogenesis in young rats

AIM

To determine the effects of valproate (VPA), carbamazepine (CBZ), oxcarbazepine (OXC), topiramate (TPM), lamotrigine (LTG), and levetiracetam (LEV) on ovarian folliculogenesis in young rats.

METHODS

Forty-nine female Wistar rats, aged 21-24 days, were divided equally into 7 experimental groups. These were given tap water over 21-24 days (control group), 300 mg/kg of VPA, 150 mg/kg of CBZ, 150 mg/kg of OXC, 100 mg/kg of TPM, 10 mg/kg of LTG, or 50 mg/kg of LEV daily in 2 doses via oral gavage until the end of puberty. At the end of the study, the estrous cycle of each rat was monitored daily, and those rats in pro-estrus or di-estrus were sacrificed and the ovaries removed. Serial sections obtained from the ovaries were stained with hematoxylin and eosin, and the corpora lutea and follicles were enumerated. Apoptotic cells were detected using the TUNEL technique. Various serial sections were immunohistochemically stained with proliferating cell nuclear antigen (PCNA), growth differentiation factor (GDF)-9, caspase-3, caspase-9, transforming growth factor beta 1 (TGF-1), and epidermal growth factor (EGF), and evaluated and photographed under a light microscope.

KEY FINDINGS

The number of corpora lutea was significantly increased in the VPA, CBZ, OXC, and LTG groups compared to the control group (p < 0.001). The number of TUNEL-positive ovarian follicles was 3.3 ± 1.1 (median, 3), 6.1 ± 0.9 (median, 6), and 5.7 ± 0.8 (median,6) in the control, OXC and LEV groups, respectively (p < 0.001). The number of TUNEL-positive granulosa cells was higher in all the groups treated with antiepileptics, with the exception of the TPM group, compared to the control group (p < 0.001). HSCOREs for immunohistochemical staining using PCNA, GDF-9, TGF-1 and EGF were significantly higher in the control group than in the others (p < 0.001). HSCORE for staining using caspase-3 was significantly higher in the VPA, CBZ, OXC and LEV groups, while the HSCORE was significantly lower in the TPM group than in the control group. HSCORE for staining using caspase-9 was significantly higher in the VPA, CBZ and OXC groups, while it was significantly lower in the TPM group than in the control group (p < 0.001).

SIGNIFICANCE

Exposure to VPA, CBZ, OXC, TPM, LTG and LEV caused different levels of impaired folliculogenesis in young rats.

HIV Drug Efavirenz Inhibits CYP21A2 Activity with Possible Clinical Implications

BACKGROUND

The HIV drugs lopinavir and ritonavir have recently been reported to cause transient adrenal insufficiency in preterm newborns. We, therefore, considered HIV drugs as a cause of transiently elevated 17-hydroxyprogesterone (17OHP) levels in a neonatal screening test for congenital adrenal hyperplasia in a preterm girl exposed to zidovudine, efavirenz, tenofovir, and emtricitabine.

OBJECTIVE

So far, HIV drugs have not been tested for their effect on steroidogenesis and the steroidogenic enzyme activity of CYP21A2 specifically in an in vitro system.

METHODS

We tested the effect of efavirenz, tenofovir, emtricitabine, and zidovudine on steroidogenesis of human adrenal H295R cells. Cells were treated with the drugs at different concentrations including concentrations in therapeutic use. The effect on CYP21A2 activity was assessed by testing the conversion of radiolabeled 17OHP to 11-deoxycortisol. Cell viability was tested by an MTT assay. In addition, recombinant human CYP21A2 protein was used to assess direct drug effects on CYP21A2 activity.

RESULTS

We observed significantly decreased CYP21A2 activity in both in vitro testing systems after treatment with efavirenz at therapeutic concentrations. Moreover, efavirenz affected cell viability. By contrast, the other test drugs did not affect steroidogenesis. Follow-up of our patient revealed elevated 17OHP and androgen levels during the first weeks of life, but values normalized spontaneously. Genetic testing for CYP21A2 mutations was negative. Thus, it remains unsettled whether the transient 17OHP elevation in this baby was due to a drug effect.

CONCLUSION

The HIV drug efavirenz inhibits CYP21A2 activity in vitro through direct interaction with enzyme catalysis at therapeutic concentrations. This may have clinical implications for HIV treatment in children and adults. However, so far, clinical data are scarce, and further studies are needed to be able to draw clinical conclusions.

The anti-epileptic drug lamotrigine inhibits the CYP17A1 lyase reaction in vitro

The potential endocrine disrupting effects of the commonly prescribed anti-epileptic drug lamotrigine (LAM) were investigated using the H295R steroidogenic in vitro assay and computational chemistry methods. The H295R cells were exposed to different concentrations of LAM, and a multi-steroid LC-MS/MS method was applied to quantify the amount of secreted steroid hormones. LAM affected several steroid hormones in the steroidogenesis at therapeutic concentrations. All progestagens as well as 11-deoxycorticosterone and corticosterone increased 100-200% with increasing concentrations of LAM suggesting a selective inhibitory effect of LAM on CYP17A1, in particular on the lyase reaction. Recombinant CYP17A1 assay confirmed the competitive inhibition of LAM toward the enzyme with IC50 values of 619 and 764 μM for the lyase and the hydroxylase reaction, respectively. Levels of androstenedione and testosterone decreased at LAM concentrations above the therapeutic concentration range. The ability of LAM to bind to CYP17A1, CYP19A1, and CYP21A2 was investigated using docking and molecular dynamics simulations. This in silico study showed that LAM was able to bind directly to the heme iron in the active site of CYP17A1, but not CYP21A2, thus supporting the results of the in vitro studies. The molecular dynamics simulations also suggested binding of LAM to the heme iron in the CYP19A1 active site. No inhibition of the aromatase enzyme was, however, observed in the H295R assay. This could be due to a sequential effect within the steroidogenesis caused by the inhibition of CYP17A1, which reduced the amounts of androgens available for CYP19A1.

Metformin inhibits human androgen production by regulating steroidogenic enzymes HSD3B2 and CYP17A1 and complex I activity of the respiratory chain

Metformin is treatment of choice for the metabolic consequences seen in polycystic ovary syndrome for its insulin-sensitizing and androgen-lowering properties. Yet, the mechanism of action remains unclear. Two potential targets for metformin regulating steroid and glucose metabolism are AMP-activated protein kinase (AMPK) signaling and the complex I of the mitochondrial respiratory chain. Androgen biosynthesis requires steroid enzymes 17α-Hydroxylase/17,20 lyase (CYP17A1) and 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2), which are overexpressed in ovarian cells of polycystic ovary syndrome women. Therefore, we aimed to understand how metformin modulates androgen production using NCI-H295R cells as an established model of steroidogenesis. Similar to in vivo situation, metformin inhibited androgen production in NCI cells by decreasing HSD3B2 expression and CYP17A1 and HSD3B2 activities. The effect of metformin on androgen production was dose dependent and subject to the presence of organic cation transporters, establishing an important role of organic cation transporters for metformin's action. Metformin did not affect AMPK, ERK1/2, or atypical protein kinase C signaling. By contrast, metformin inhibited complex I of the respiratory chain in mitochondria. Similar to metformin, direct inhibition of complex I by rotenone also inhibited HSD3B2 activity. In conclusion, metformin inhibits androgen production by mechanisms targeting HSD3B2 and CYP17-lyase. This regulation involves inhibition of mitochondrial complex I but appears to be independent of AMPK signaling.

Variation in 3β-hydroxysteroid dehydrogenase activity and in pregnenolone supply rate can paradoxically alter androstenedione synthesis

The 3β-hydroxysteroid dehydrogenase/Δ(5)-Δ(4) isomerase (3β-HSD) and 17α-hydroxylase/17,20-lyase cytochrome P450 (P450c17) enzymes are important in determining the balance of the synthesis of different steroids such as progesterone (P4), glucocorticoids, androgens, and estrogens. How this is achieved is not a simple matter because each of the two enzymes utilizes more than one substrate and some substrates are shared in common between the two enzymes. The two synthetic pathways, Δ(4) and Δ(5), are interlinked such that it is difficult to predict how the synthesis of each steroid changes when any of the enzyme activities is varied. In addition, the P450c17 enzyme exhibits different substrate specificities among species, particularly with respect to the 17,20-lyase activity. The mathematical model developed in this study simulates the network of reactions catalyzed by 3β-HSD and P450c17 that characterizes steroid synthesis in human, non-human primate, ovine, and bovine species. In these species, P450c17 has negligible 17,20-lyase activity with the Δ(4)-steroid 17α-hydroxy-progesterone (17OH-P4); therefore androstenedione (A4) is synthesized efficiently only from dehydroepiandrosterone (DHEA) through the Δ(5) pathway. The model helps to understand the interplay between fluxes through the Δ(4) and Δ(5) pathways in this network, and how this determines the response of steroid synthesis to the variation in 3β-HSD activity or in the supply of the precursor substrate, pregnenolone (P5). The model simulations show that A4 synthesis can change paradoxically when 3β-HSD activity is varied. A decrease in 3β-HSD activity to a certain point can increase A4 synthesis by favouring metabolism through the Δ(5) pathway, though further decrease in 3β-HSD activity beyond that point eventually limits A4 synthesis. The model also showed that due to the competitive inhibition of the enzymes' activities by substrates and products, increasing the rate of P5 supply above a certain point can suppress the synthesis of A4, DHEA, and 17OH-P4, and consequently drive more P5 towards P4 synthesis.

The steroid metabolome in lamotrigine-treated women with epilepsy

BACKGROUND

Epilepsy in women may be associated with reproductive disorders and alterations in serum steroid levels. Some steroids can be induced by epilepsy and/or treatment with antiepileptic drugs; however, there are still limited data available concerning this effect on the levels of other neuroactive steroid metabolites such as 3a-hydroxy-5a/b-reduced androstanes.

AIM

To evaluate steroid alterations in women with epilepsy (WWE) on lamotrigine monotherapy.

SUBJECTS AND METHODS

Eleven WWE and 11 age-matched healthy women underwent blood sampling in both phases of their menstrual cycles (MCs). The steroid metabolome, which included 30 unconjugated steroids, 17 steroid polar conjugates, gonadotropins, and sex hormone-binding globulin (SHBG), was measured using gas chromatography-mass spectrometry (GC-MS) and radioimmunoassay (RIA).

RESULTS

WWE had lower cortisol levels (status p<0.001), but elevated levels of unconjugated 17-hydroxypregnenolone (status p<0.001). Progesterone was higher in the follicular menstrual phase (FP) in WWE than in the controls (status×menstrual phase p<0.05, Bonferroni multiple comparisons p<0.05), whereas 17-hydroxyprogesterone was higher in WWE in both menstrual phases (status p<0.001). The steroid conjugates were mostly elevated in WWE. The levels of 5α/β-reduced androstanes in WWE that were significantly higher than the controls were etiocholanolone (status p<0.001), 5α-androstane-3α,17β-diol (status p<0.001), and the 5α/β-reduced androstane polar conjugates (status p<0.001).

CONCLUSIONS

WWE showed a trend toward higher circulating 3α-hydroxy-5α/β-reduced androstanes, increased activity of 17α-hydroxylase/17,20 lyase in the Δ(5)-steroid metabolic pathway, and increased levels of the steroid polar conjugates.

Impact of differential P450c17 phosphorylation by cAMP stimulation and by starvation conditions on enzyme activities and androgen production in NCI-H295R cells

CYP17A1 plays a pivotal role in the biosynthesis of androgens in the adrenals and the gonads. Although this enzyme catalyzes two different reactions on one single active site, its specific activities are regulated independently. Although the 17alpha-hydroxylase activity is rather constant and regulated by gene expression, the 17,20-lyase activity varies significantly with the amount of cofactors or by protein phosphorylation. cAMP increases CYP17A1 expression, P450c17 phosphorylation, and androgen production. However, the exact mechanism(s) and the specific regulators of CYP17A1 remain unknown. Therefore, we studied the regulation of adrenal androgen biosynthesis in human adrenal H295R cells focusing on CYP17A1. We analyzed androgen production and P450c17 activities in H295R cells grown under normal and serum-free conditions and/or after stimulation with 8-bromoadenosine-cAMP. H295R cells grown in starvation medium produced more androgens and had decreased HSD3B2 expression and activity but increased P450c17-17,20-lyase activity and serine phosphorylation. Although starvation increased serine phosphorylation of P450c17 specifically, cAMP stimulation enhanced threonine phosphorylation exclusively. Time-course experiments revealed that a short cAMP stimulation augmented threonine phosphorylation of P450c17 but did not increase 17,20-lyase activity. By contrast, long cAMP stimulation increased androgen production through increased P450c17 activities by enhancing CYP17A1 gene expression. We conclude that serum withdrawal shifts steroidogenesis of H295R cells towards androgen production, providing a suitable model for detailed studies of androgen regulation. In addition, our study shows that starvation and cAMP stimulation regulate P450c17 phosphorylation differentially and that an increase in P450c17 phosphorylation does not necessarily lead to enhanced enzyme activity and androgen production.

Inhibitory effect of valproic acid on ovarian androgen biosynthesis in rat theca-interstitial cells

The objective of the study was to evaluate the effect of valproic acid (VPA) on ovarian androgen biosynthesis in primary cultures of theca-interstitial (T-I) cells isolated from rat ovaries. Ovarian T-I cells were cultured with VPA in the presence or absence of hCG. VPA did not increase basal or hCG-stimulated androgen synthesis when added to primary cultures of T-I cells. However, the addition of VPA caused a marked concentration-dependent inhibitory effect on hCG-stimulated androstendione synthesis. Treatment of T-I cells with 8-Bromo-cAMP resulted in a marked increase in the production of androstenedione, and VPA inhibited this stimulatory effect, suggesting that the mechanism of VPA's inhibitory effect on androstenedione production occurs at a step after second messenger activation. Treatment of T-I cells with hCG resulted in a significant increase in the mRNA expression of steroidogenic enzymes CYP17A1 and 17β-hydroxysteroid dehydrogenase. Addition of VPA sharply blunted the stimulatory effect of hCG, reducing the mRNA expression of the steroidogenic enzymes to basal levels. In conclusion, VPA exerts an inhibitory effect on hCG-stimulated androgen synthesis in rat T-I cells.

Menstrual cycle dysfunction associated with neurologic and psychiatric disorders: their treatment in adolescents

Epilepsy, bipolar disorder, and migraines are common disorders that are often associated with disturbances in menstrual function in adolescent girls. Women with untreated epilepsy are more likely to have irregular menstrual cycles than are nonepileptic controls, indicating that the disease itself plays a role in the etiology of these reproductive abnormalities. In addition, many girls with these disorders require chronic maintenance treatment with agents that may perturb the hypothalamic-pituitary-ovarian axis. Valproate is a highly effective antiepileptic drug used widely to treat epilepsy, bipolar disorder, and migraines. Valproate induces features of the polycystic ovary syndrome (PCOS) in approximately 7% of women. Girls with epilepsy, and possibly bipolar disorder, appear particularly susceptible to developing PCOS features on valproate, perhaps on account of the relative immaturity of their hypothalamic-pituitary-ovarian axes. Antipsychotics are highly effective drugs used widely to treat adolescents with bipolar disorder, psychotic disorders, and behavioral disturbances. Some, but not all of the antipsychotic, induce hyperprolactinemia, which may result in oligo- or amenorrhea. Prolonged amenorrhea in association with hyperprolactinemia incurs significant risks for bone health in adolescent girls. Because of the potential reproductive health risks associated with use of specific antiepileptic drugs and selective antipsychotics, these agents are vital treatments for adolescents with severe illnesses. Use of these agents should be considered and weighed against the risk of using alternative agents, which have their own side effects, or not treating these serious neurologic and psychiatric disorders.

Association of Polycystic Ovary Syndrome with Anticonvulsant Use: ACase Report

A 20-year-old woman with epilepsy had resolution of features of polycystic ovary syndrome on discontinuing valproic acid; they reappeared with the newer antiepileptic divalproex sodium.

Drugs and HPA axis

This paper outlines the interferences of the most widely used drugs with hypothalamo-pituitary-adrenal function and the related laboratory parameters, with the purpose of providing practical help to clinicians during testing for hypo- or hypercortisolemic states.