Modulation of leukotriene D4 attenuates the development of seizures in mice

The present study has been designed to pharmacologically investigate the effect of Montelukast sodium, a leukotriene D₄ receptor antagonist, and 1,2,3,4, tetrahydroisoquinoline, a leukotriene D₄ synthetic pathway inhibitor, on the pathophysiological progression of seizures using mouse models of kindled epilepsy and status epilepticus induced spontaneous recurrent seizures. Pentylenetetrazole (40 mg kg⁻¹) (PTZ) administration every second day for a period of 15 d was used to elicit chemically induced kindled seizure activity in mice. In a separate set of groups, fifty consecutive electroshocks were delivered to mice using corneal electrodes with continuously increasing intensity with an inter-shock interval of 40 s. Severity of kindled seizures was assessed in terms of a composite kindled seizure severity score (KSSS). Pilocarpine (100 mg kg⁻¹) was injected every twenty minutes until the onset of status epilepticus. A spontaneous recurrent seizure severity score (SRSSS) was recorded as a measure of quantitative assessment of the progressive development of spontaneous recurrent seizures induced after pilocarpine status epilepticus. Sub-acute PTZ administration and electroshock induced the development of severe form of kindled seizures in mice. Severity of kindled seizures was assessed in terms of a composite kindled seizure severity score. Further, pharmacological status epilepticus elicited a progressive evolution of spontaneous recurrent seizures in the animals. However, Montelukast sodium, a leukotriene D₄ receptor antagonist, as well as 1,2,3,4, tetrahydroisoquinoline, a leukotriene D₄ synthetic pathway inhibitor, markedly and dose dependently suppressed the development of kindled seizures as well as pilocarpine induced spontaneous recurrent seizures. Therefore, leukotriene D₄ may be implicated in the pathogenesis of seizures.     

Biphasic activity of resveratrol on indomethacin-induced gastric ulcers

Resveratrol showed biphasic activity in indomethacin-induced gastric ulcerated mice. A protective effect at a lower dose (2 mg kg⁻¹) and a contraindicative effect at a higher dose of Resveratrol (10 mg kg⁻¹) were observed. This phenomenon was possibly controlled by a COX-1 and eNOS balance, which ultimately maintained angiogenesis in Resveratrol-treated pre-ulcerated mice. The lower dose of Resveratrol (2 mg kg⁻¹) augmented eNOS expression without altering COX-1 expression, but, at a higher dose (10 mg kg⁻¹), Resveratrol predominantly suppressed COX-1 expression, which significantly reduced both PGE₂ synthesis and angiogenesis. Thus it ultimately resulted in delay healing of indomethacin-induced gastric ulcers. Hence, it could be concluded that COX-1 and eNOS acted as key regulatory factors switching the biphasic effects of Resveratrol in indomethacin-induced ulcerated mice.     

(4S)-4-amino-5,6-heptadienoic acid (MDL 72483): A potent anticonvulsant GABA-T inhibitor

(4S)-4-Amino-5,6-heptadienoic acid ((S)--allenyl-GABA; MDL 72483) is a potent inactivator of brain GABA-T in mice; (ED₅₀ (i.p.)=60 mg·kg^–1; ED₅₀ (oral)=70 mg·kg^–1). Its anticonvulsant effects against 3-mercaptopropionic acid (MPA)-induced seizures in mice is related to the elevation of whole brain GABA concentrations: The mentioned doses of MDL 72483 which cause a decrease of GABA-T activity by 50%, produce within 5 h after dosing an increase of GABA concentration by about 3 mol·g^–1, and protect 50% of the mice against seizures in this model of presynaptic GABA deficit. When given orally MDL 72483 is about five times more potent than vigabatrin ((4R/S)-4-amino-5-hexenoic acid) a known antiepileptic GABA-T inhibitor. Complete protection was achieved with a dose of 150 mg·kg^–1. Similar to vigabatrin, MDL 72483 does not protect significantly against metrazol-induced convulsions. However, at a dose of 300 mg·kg^–1, the time elapsing between metrazol administration and onset of convulsions was prolonged by a factor of 3.4. Oral administration of MDL 72483 for up to 19 days at a daily dose of 91–96 mg·kg^–1 did not produce any obvious behavioral changes in mice, nor was the ED₅₀ of the drug in MPA-seizure tests significantly altered by the pretreatment. These observations indicate that MDL 72483 is a promising drug for the treatment of certain epilepsies.Special issue dedicated to Dr. Eugene Roberts.     

Fractions composition study of the pyrolysis oil obtained from sewage sludge treatment plant

In this work the parameters of Low Temperature Conversion - LTC were applied in a centrifuged sludge from a sewage treatment plant located in Rio de Janeiro, Brazil. Before the conversion, the sludge was dried and analyzed by TGA to observe its behavior with increasing temperature. The chemical composition of the crude pyrolysis oil was analyzed by FTIR, ¹H NMR and GC-MS. The results showed that the oil is a mixture of hydrocarbons, oxygenated and nitrogenated compounds. Using a catalytic treatment it was possible to fractionate the oil where the predominant constituents were hydrocarbons showing that the cracking was effective. An important result was the difference between the calorific value of dry sludge (10 MJ kg⁻¹), the pyrolysis oil (36 MJ kg⁻¹) and one of the fractions separated by catalytic cracking (40 MJ kg⁻¹) when compared with commercial diesel (45 MJ kg⁻¹).     

Accumulation, speciation, and coordination of arsenic in an inbred line and a wild type cultivar of the desert plant species Chilopsis linearis (Desert willow)

This study investigated the absorption of arsenic (As), sulfur (S), and phosphorus (P) in the desert plant Chilopsis linearis (Desert willow). A comparison between an inbred line (red flowered) and wild type (white flowered) plants was performed to look for differential responses to As treatment. One month old seedlings were treated for 7 days with arsenate (As₂O₅, As^V) at 0, 20, and 40 mg As^V L⁻¹. Results from the ICP-OES analysis showed that at 20 mg As^V L⁻¹, red flowered plants had 280 ± 11 and 98 ± 7 mg As kg⁻¹ dry wt in roots and stems, respectively, while white flowered plants had 196 ± 30 and 103 ± 13 mg As kg⁻¹ dry wt for roots and stems. At this treatment level, the concentration of As in leaves was below detection limits for both plants. In red flowered plants treated with 40 mg As^V L⁻¹, As was at 290 ± 77 and 151 ± 60 mg As kg⁻¹ in roots and stems, respectively, and not detected in leaves, whereas white flowered plants had 406 ± 36, 213 ± 12, and 177 ± 40 mg As kg⁻¹ in roots, stems, and leaves. The concentration of S increased in all As treated plants, while the concentration of P decreased in roots and stems of both types of plants and in leaves of red flowered plants. X-ray absorption spectroscopy analyses demonstrated partial reduction of arsenate to arsenite in the form of As-(SX)₃ species in both types of plants.     

Ketamine prevents seizures and reverses changes in muscarinic receptor induced by bicuculline in rats

The cholinergic system has been implicated in several experimental epilepsy models. In a previous study bicuculline (BIC), known to antagonize GABA-A postsynaptic receptor subtype, was administered to rats at subconvulsant (1 mg/kg) and convulsant (7.5 mg/kg) doses and quinuclidinyl benzilate ([³H]-QNB) binding to CNS membranes was determined. It was observed that ligand binding to cerebellum increases while it decreases in the case of hippocampus. Saturation binding curves showed that changes were due to the modification of receptor affinity for the ligand without alteration of binding site number. The purpose of this study was to assay muscarinic receptors employing other BIC dose (5 mg/kg), which induces seizures and allows the analysis of a postseizure stage as well. To study further muscarinic receptor involvement in BIC induced seizures, KET was also employed since it is a well known anticonvulsant in some experimental models. The administration of BIC at 5 mg/kg to rats produced a similar pattern of changes in [³H]-QNB binding to those recorded with 1.0 and 7.5 mg/kg doses. Here again, changes were observed in receptor binding affinity without alteration in binding site number for cerebellum or hippocampus membranes. Pretreatment with KET (40 mg/kg) prevented BIC seizures and reverted [³H]-QNB binding changes induced by BIC administration. The single administration of KET invariably resulted in [³H]-QNB binding decrease to either cerebellar or hippocampal membranes. KET added in vitro decreased ligand binding likewise. Results of combined treatment with KET plus BIC are hardly attributable to the single reversion of BIC effect since KET alone invariably decreased ligand binding. It is suggested that besides alteration of cholinergic muscarinic receptor other(s) neurotransmitter system(s) may well also be involved.     

Activity of elaeochytrin A from Ferula elaeochytris on leukemia cell lines

Phytochemical investigation of the roots of Ferula elaeochytris made it possible to isolate two sesquiterpene esters, 6-anthraniloyljaeschkeanadiol (elaeochytrin A) and 4β-hydroxy-6α-(p-hydroxybenzoyloxy)dauc-9-ene (elaeochytrin B), as well as eight known compounds: 6-angeloyljaeschkeanadiol, teferidin, ferutinin, 6-(p-hydroxybenzoyl)epoxyjaeschkeanadiol, 6-(p-hydroxybenzoyl)lancerotriol, 5-caffeoylquinic acid, 1,5-dicaffeoylquinic acid and sandrosaponin IX. The cytotoxic activities of all compounds were investigated on K562R (imatinib-resistant) human chronic myeloid leukaemia and DA1-3b/M2^BCR-ABL (dasatinib-resistant) mouse leukemia cell line. Elaeochytrin A was the most active compound on both cell lines (IC₅₀ = 12.4 and 7.8 μM, respectively). It was also tested on non-resistant human promyelocytic leukemia cells (HL60, IC₅₀ = 13.1 μM) and was not toxic to normal peripheral blood mononuclear cells up to 100 μM.     

Antioxidant activity elicited by low dose of caffeine attenuates pentylenetetrazol-induced seizures and oxidative damage in rats

Although caffeine supplementation has a beneficial effect on people with neurological disorders, its implications for oxidative damage related to seizures are not well documented. Thus the aim of this study was to investigate the effects of two weeks caffeine supplementation (6 mg/kg; p.o.) on seizures and neurochemical alterations induced by pentylenetetrazol (PTZ 60 mg/kg i.p.). Statistical analyses showed that long-term rather than single dose caffeine administration decreased the duration of PTZ-induced seizures in adult male Wistar rats as recorded by cortical electroencephalographic (EEG) and behavioral analysis. The quantification of EEG recordings also revealed that caffeine supplementation protected against a wave increase induced by PTZ. Neurochemical analyses revealed that caffeine supplementation increased glutathione (GSH) content per se and protected against the increase in the levels of thiobarbituric acid reactive substances (TBARS) and oxidized diclorofluoresceine diacetate (DCFH-DA). Also, caffeine prevent the decrease in GSH content and Na⁺, K⁺-ATPase activity induced by PTZ. Our data also showed that the infusion of L-buthionine sulfoximine (BSO; 3.2 μmol/site i.c.v), an inhibitor of GSH synthesis, two days before injecting PTZ reversed the anticonvulsant effect caused by caffeine. BSO infusion also decreased GSH content and Na⁺, K⁺-ATPase activity. However, it increased DCFH-DA oxidation and TBARS per se and reversed the protective effect of caffeine. Results presented in this paper support the neuroprotective effects of low long-term caffeine exposure to epileptic damage and suggest that the increase in the cerebral GSH content caused by caffeine supplementation may provide a new therapeutic approach to the control of seizure.     

Vitellogenesis and other physiological responses induced by 17-β-estradiol in males of freshwater fish Rhamdia quelen

This study investigated the effects of different doses of 17-β-estradiol (E₂) in Rhamdia quelen. Groups of males exposed to different doses of E₂ (0.1 mg kg^− 1, 1 mg kg^− 1 and 10 mg kg^− 1) were compared with non-exposed male and female fish groups. Among the considered biomarkers, no significant differences were observed for micronuclei test, reduced glutathione concentration and lipid peroxidation. All E₂-treated individuals had decreased glutathione S-transferase activity. Increased catalase and superoxide dismutase activities, increased vitellogenin expression and decreased metallothionein concentration were observed in males treated with the highest dose. Liver of all test groups showed necrotic areas, but cytoplasm vacuolization was again found only in the individuals exposed to highest dose. E₂ causes deleterious hepatic effects to R. quelen, and vitellogenin expression, catalase and superoxide dismutase activity and metallothionein concentration represent appropriate biomarkers for studying E₂ effects. Additionally, the response of some biomarkers was similar in males exposed to E₂ and unexposed females, and therefore exposure to endocrine disruptors may cause consequences for fish populations.     

Pharmacological inhibition of inducible nitric oxide synthase attenuates the development of seizures in mice

The present study has been designed to pharmacologically expound the significance of inducible nitric oxide synthase in the pathophysiological progression of seizures using mouse models of chemically induced kindled epilepsy and status epilepticus induced spontaneous recurrent seizures. Pentylenetetrazole (40 mg kg⁻¹) (PTZ) administration every second day for a period of 15 days was used to elicit kindled seizure activity in mice. Severity of kindled seizures was assessed in terms of a composite kindled seizure severity score (KSSS). Pilocarpine (100 mg kg⁻¹) was injected every 20 min until the onset of status epilepticus. A spontaneous recurrent seizure severity score (SRSSS) was recorded as a measure of quantitative assessment of the progressive development of spontaneous recurrent seizures induced after pilocarpine status epilepticus. Sub-acute PTZ administration induced the development of severe form of kindled seizures in mice. Further, pharmacological status epilepticus elicited a progressive evolution of spontaneous recurrent seizures in the animals. However, treatment of aminoguanidine, a relatively selective inhibitor of inducible nitric oxide synthase, markedly and dose dependently suppressed the development of both PTZ induced kindled seizures as well as pilocarpine induced spontaneous recurrent seizures. Therefore inducible nitric oxide synthase may be implicated in the development of seizures.     

Oxalate production at different initial Pb²+ concentrations and the influence of oxalate during solid-state fermentation of straw with Phanerochaete chrysosporium

The production of oxalate at different initial Pb²⁺ concentrations during solid-state fermentation of straw with Phanerochaete chrysosporium was investigated. It was found that the maximal peak value of oxalate concentration (22.84 mM) was detected at the initial Pb²⁺ concentration of 200 mg kg⁻¹ dry straw, while the minimum (15.89 mM) at the concentration of 600 mg Pb²⁺ kg⁻¹ dry straw, and at moderate concentration of Pb²⁺ the capability of oxalic acid secretion was enhanced. In addition, it was also found that more oxalic acid accumulation went together with better Pb²⁺ passivation effect and higher manganese peroxidase (MnP) activity. The present findings will improve the understandings of the interactions of heavy metals with white-rot fungi and the role of oxalate in lignin degradation system, which could provide useful references for more efficient treatment of Pb-contaminated lignocellulosic waste.     

Doxycycline could aggravate the absence-like epileptic seizures of WAG/Rij rats via matrix metalloproteinase inhibition

Matrix metalloproteinases (MMPs) are known to be activated in the brain by epileptic seizures and elevated MMP-9 activity has been found in a genetic model of generalized absence epilepsy (Wistar Albino Glaxo Rijswijk/WAG/Rij rats). In this study we posed the question, whether MMP inhibitory dose of doxycycline (20 mg/kg) could affect the spike-wave-discharges (SWDs) of the WAG/Rij rat. We found that intraperitoneal (i.p.) administration of 20 mg/kg doxycycline significantly increased the incidence and duration of SWDs for 4 h. As doxycycline has both MMP inhibitory and anti-inflammatory effects we also tested a lower dose of doxycycline (10 mg/kg, i.p.) and a selective broad-spectrum MMP inhibitor GM6001 (N-[2(R)-2-(hydroxamido carbonylmethyl)-4-methylpentanoyl]-l-tryptophane methylamide) intracerebroventricularly (i.c.v., 10 ng/rat). While 10 mg/kg doxycycline significantly increased the SWD number for 1 h, GM6001 significantly increased the SWD number during the whole 4-h recording period. Our results could indicate that the induction of MMPs in the epileptic brain, besides contributing to structural remodeling, would also be associated with such functions as homeostatic synaptic plasticity which might counteract epileptic seizures.     

Age-related intramuscular pharmacokinetics of cefquinome in sheep

The pharmacokinetic profile of cefquinome was studied in one, six-months and one year old sheep following a single intramuscular doses of 1 and 10 mg kg⁻¹ b.wt. Cefquinome concentrations in serum were determined by microbiological assay technique using Micrococcus luteus (ATCC 9341) as test organism. Following intramuscular administration of cefquinome, the absorption half-lives (t_0.5(ab)) were 1.540, 1.037 and 0.664 h at a dose of 1 mg kg⁻¹ b.wt. and 1.844, 1.290 and 1.605 h at a dose of 10 mg kg⁻¹ b.wt. in the three ages, respectively. After the two doses, the maximum serum concentrations (C_max) of 0.732, 1.145, 1.205 and 3.525, 5.088, 4.576 μg ml⁻¹ were attained after (t_max) of 3.812, 3.029, 2.174 and 3.785, 2.824, 3.095 h in the three ages, respectively. The elimination half-life (t_0.5(el)) and MRT values of cefquinome were longer in one-month old sheep compared to six-months old and yearling sheep. The absorption and elimination processes were delayed in newborn sheep of one-month old in contrary to six-month and yearling animals. The in vitro serum protein-binding tendencies were 8.254%, 11.586% and 13.002%, for one, six-months and one year old sheep, respectively. Based on this study and economically, an optimal intramuscular dosage regimen of cefquinome would be 1 mg kg⁻¹ once daily in one-month, six-months and one-year old sheep to achieve and maintain the therapeutic serum levels within safe limits.     

Zinc incorporation in the otoliths of juvenile pink snapper (Pagrus auratus Forster): The influence of dietary versus waterborne sources

Separate laboratory experiments were conducted to examine if incorporation of Zn into the otoliths of juvenile pink snapper (Pagrus auratus Forster) was related to levels in the food and/or water. In the first experiment, fish were fed a regular diet (600 mg Zn kg^− 1 dw, control group) or a Zn-enriched diet (6000 mg Zn kg^− 1 dw or 9000 mg Zn kg^− 1 dw) for 35 days. In the second experiment, fish were exposed to waterborne Zn concentrations of < 0.005 µg L^− 1 (control), 50 µg L^− 1, 100 µg L^− 1 and 200 µg L^− 1 for 35 days. The sagittal otoliths were analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Juvenile fish exposed to higher concentrations of waterborne Zn did not display increased Zn levels in their otoliths. However, Zn levels in the otoliths of fish consuming the Zn-enriched diet were significantly higher relative to control fish. This study clearly demonstrated that dietary Zn was the major source of Zn incorporated into the otoliths by this marine fish.     

Synthesis and characterization of a molecularly imprinted polymer and its application as SPE enrichment sorbent for determination of trace methimazole in pig samples using HPLC-UV

A novel molecularly imprinted polymer that could be applied as enrichment sorbent was prepared using methimazole (MMZ) as the template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker. Though evaluated by static, kinetic and competitive adsorption tests, the polymer exhibited high adsorption capacity, fast kinetics and good selective ability. A method for determination of trace MMZ was developed using this polymer as enrichment sorbent coupled with high performance liquid chromatography focusing on complex biological matrices. Under the optimum experimental conditions, the MMZ standard is linear within the concentration range studied, that is, from 0.5 μg L⁻¹ to 150 μg L⁻¹ (r² = 0.9941). Lower limits of detection (LOD, at S/N = 3) and quantification (LOQ, at S/N = 10) in pig samples were 0.63 μg kg⁻¹ and 2.10 μg kg⁻¹ for kidney, 0.51 μg kg⁻¹ and 1.70 μg kg⁻¹ for liver, 0.56 μg kg⁻¹ and 1.86 μg kg⁻¹ for muscle, respectively. Recoveries and relative standard deviation (RSD, n = 9) values for precision in the developed method were from 71.14% to 88.41% and from 2.53% to 6.18%.     

Magnetic and catalytic properties of a new copper(II)-Schiff base 2D coordination polymer formed by connected helical chains

A dicyanamide bridged 2D polynuclear complex of copper(II) having molecular formula [Cu₂(L)(μ_1,5-dca)₂]_n (1) has been synthesized using the Schiff base ligand N,N′-bis(salicylidene)-1,3-diaminopentane, (H₂L) and sodium dicyanamide (dca). The complex presents a 2D hexagonal structure formed by 1,5-dca singly bridged helical chains connected through double 1,5-dca bridges. The chelating characteristics of the H₂L Schiff base ligand results in the formation of copper(II) dimer with a double phenoxo bridge presenting a very strong antiferromagnetic coupling in the copper(II) derivative (1) (J = −510 cm⁻¹). The dimeric asymmetric unit of 1 is very similar to the active site of the catechol oxidase and, as expected, also presents catalytic activity for the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone in presence of O₂, as demonstrated by kinetic studies of this oxidation reaction monitored by absorption spectroscopy resulting in high turnover number (K_cat = 259 h⁻¹).     

Remediation of chromite ore processing residue by pyrolysis process with sewage sludge

The present work developed a novel technique to treat chromite ore processing residue (COPR). The process involved mixing the COPR with sewage sludge followed by pyrolysis. The gaseous organic fraction generated during pyrolysis of sludge was beneficial to Cr(VI) reduction. Process variables, such as the amount of sludge added to COPR (sludge-to-COPR (S/C) ratio), heating temperature, reaction time and particle size, were systematically varied, and their influences on the Cr(VI) reduction in COPR were investigated. Cr(VI) content had decreased greatly, from 3384 mg kg⁻¹ for untreated COPR to less than 30 mg kg⁻¹ for COPR treated at 600 °C.     

Antibacterial and antioxidant activities of four kaempferol methyl ethers isolated from Dodonaea viscosa Jacq. var. angustifolia leaf extracts

Fractionation of dichloromethane and acetone fractions obtained by serial extraction from the leaf powder of Dodonaea viscosa Jacq. var. angustifolia (Sapindaceae) resulted in the isolation of four kaempferol methyl ethers. The compounds were identified by spectral data (¹H NMR, ¹³C NMR and MS) as: 3, 5, 7-trihydroxy-4'-methoxyflavone (1); 5, 7, 4'-trihydroxy-3, 6-dimethoxyflavone (2); 5, 7-dihydroxy-3, 6, 4'-trimethoxyflavone (santin) (3); and 5-hydroxy -3, 7, 4'-trimethoxyflavone (4) together with 3,4',5,7-tetrahydroxy flavone (kaempferol) (5). Antioxidant potential of the compounds was evaluated using a DPPH spectrophotometric assay, while antibacterial activity was determined using a serial dilution microplate technique. The isolates demonstrated varying degrees of antioxidant and antibacterial activities. Of all the compounds investigated, compounds 1 and 5 demonstrated some antioxidant activity (EC₅₀ = 75.49 ± 1.76 µM and 35.06 ± 0.85 respectively) but lower than l-ascorbic acid (EC₅₀ = 13.55 ± 0.28 µM) used as a standard antioxidant agent. The minimum inhibitory concentration (MIC) of isolated compounds against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa varied from 16 µg/ml to more than 250 µg/ml. Some structure activity relationships could be established for these compounds.     

The expression of serum steroid sex hormones and steroidogenic enzymes following intraperitoneal administration of dehydroepiandrosterone (DHEA) in male rats

The adrenals of humans and primates could secrete large amounts of dehydroepiandrosterone (DHEA) and its sulphate ester (DHEA-S) in the circulation, which act as precursors of active steroid hormones in a long series of peripheral target intracrine tissues. The marked decline of serum DHEA and DHEA-S concentrations with age in humans has been incriminated in the development of various pathologies. Therefore, this study aims to provide detailed information on the effects of the intraperitoneal injection of DHEA on circulating steroid hormones and their metabolites and their trade-off relationship over 24 h in male rats. In this study, 100 healthy adult male Sprague-Dawley (SD) rats were randomly divided into three groups: control, 25 mg kg⁻¹ DHEA-treated and 100 mg kg⁻¹ DHEA-treated. The animals were sacrificed at 0, 1.5, 3, 6, 12 or 24 h, and the samples were collected for subsequent analysis. Total cholesterol (TC) markedly decreased 3 h after the administration of 100 mg kg⁻¹ DHEA, but markedly increased 12 h after administration. The DHEA-S, progesterone (P), testosterone (T), oestradiol (E₂), cortisol (Cor) and aldosterone (Ald) concentrations also markedly increased after DHEA administration, with serum DHEA-S, T, E₂ and Cor levels peaking at 1.5 h. Over time, steroid hormone levels were depressed, but serum Cor and Ald levels were markedly elevated relative to the control group at 24 h. Furthermore, DHEA treatment produced a significant increase in P450scc, 17β-HSDIII, CYP17α and 3β-HSD mRNA expression at 1.5 h, but a decided decrease in P450scc and StAR mRNA expression at 12 and 24 h, and CYP17α and 17β-HSDIII expression at 12 h in the 100 mg kg⁻¹ DHEA group. In total, the results of the present study indicate that DHEA at high pharmacological doses may affect steroid through an effect on steroidogenic enzymes.