Steroidogenic Enzyme Activities Research Articles

Effect of Excess Iodine on Oxidative Stress Markers, Steroidogenic-Enzyme Activities, Testicular Morphology, and Functions in Adult Male Rats.

Improper iodine intake is a major concern in public health. Chronic intake of low iodine affects gonadal functions of man and animals; however, such effects of excess iodine in male reproduction, specially on testicular morphology, testicular steroidogenic enzyme activities, sperm morphology, sperm viability, and sperm count including male hormonal profiles in reference to iodine status and thyroid hormone profiles are yet to be explored. With this background, adult male rats of 120 ± 10 gm Bw of 90 ± 5days were divided broadly in two groups depending on the duration of the treatment for 30 and 60days, respectively. Both the groups consisted of control animals. Excess iodine (100EI), i.e., 100 times more than its recommended level but within its tolerable ranges, was administered through gavage regularly to the first group of experimental animals for 30 and 60days, respectively, and excessive iodine (500EI), i.e., 500 times more than its recommended level and above tolerable range in the same way and for the same durations, was administered to the other group of experimental animals. Overall results revealed that regular consumption of iodine in excess impairs reproductive functions in adult male rats depending on the dose and duration of its exposure through different mechanisms. Excess iodine accumulates in the testis which results in generation of reactive oxygen species (ROS) as evidenced by higher lipid peroxidation level as well as an imbalance in the pro-/antioxidant status inhibiting the activity of ∆(5) 3β- hydroxysteroid dehydrogenase (HSD) and 17β-HSD resulting to reduced synthesis of testosterone that causes structural and functional changes of the testis. Secondly, persistent generation of ROS in testis as a result of prolonged excess iodine exposure affects hypothalamo-pituitary-adrenal axis that stimulates synthesis and secretion of corticosterone which inhibits LH release that downregulates testosterone synthesis causing further testicular disruption. Thirdly, excess iodine when administered above its tolerable ranges for prolonged duration acts on thyroid itself developing a state of biochemical hypothyroidism (as evident by low T3) which further potentiate the disrupting effect of excess iodine on male gonads by reducing circulating testosterone level.

Longitudinal changes in serum concentrations of adrenal androgen metabolites and their ratios by LC-MS/MS in healthy boys and girls

Adrenarche is characterized by steadily rising levels of adrenal androgen metabolites from 4–6years of age. We recently described marked gender-specific differences in circulating ratios between selected adrenal androgen metabolites in a cross-sectional study. This may suggest gender differences in steroidogenic enzyme activities.We therefore aimed at verifying these findings in a prospective, longitudinal study of healthy boys and girls who were examined during pubertal transition.A longitudinal study of 20 healthy children from the COPENHAGEN Puberty Study, followed every 6months for 5years. Clinical examinations were conducted and serum concentrations of Androstenedione (Adione), 17-hydroxyprogesterone (17-OHP), testosterone (T), dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) were quantified by a newly developed LC-MS/MS method.DHEA, DHEAS, Adione, 17-OHP and T increase with age. Boys had higher levels of DHEAS from 10.5years of age, whereas girls had higher levels of Adione from 13years of age compared to boys.Interestingly, we observed significantly higher ratios of DHEAS/DHEA (sulfotransferase activity) in boys before and after pubertal onset compared to girls, whereas Adione/17-OHP (CYP 17 activity) appeared to increase more in pubertal girls compared to boys. This suggests that adrenal steroidogenic enzyme activities show developmental as well as gender-specific changes in healthy children.

Distinct Testicular Steroidogenic Response Mechanisms Between Neonatal and Adult Heat-Acclimated Male Rats

Background: In comparison to short-term gonad heat exposure, little is known about the molecular mechanisms that regulate testicular steroidogenesis during long-term whole body heat acclimation. Material and Methods: Testicular slices from neonatal (NHA) and adult (AHA) heat-acclimated Wistar rats were analysed in vitro to assess the mRNA expression and enzymatic activity of steroidogenic enzymes under basal and luteinising hormone (LH) or prolactin (PRL) stimulated conditions compared with control rats (CR). Furthermore, a de-acclimated group (DA) was created by transferring adult NHA rats to control conditions. Results: Heat acclimation significantly increased plasma LH levels in the AHA group and LH and PRL in the NHA group compared with the CR group; however, after heat acclimation, the T and E2 levels did not differ from the control levels. All heat-acclimated groups showed high basal intra-testicular steroid production in vitro. Moreover, basal Cyp11a1 and Hsd3b1 levels were upregulated in vitro in the NHA and DA groups versus the CR group. LH in vitro stimulation upregulated Cyp11a1 expression in the NHA and AHA groups and PRL stimulation upregulated Cyp17a1 levels in the NHA and DA groups compared with the basal expression levels. In the AHA group, decreased basal Star and CYP11A activities but increased HSD3B1 and CYP17A1 activities were found. Conclusion: Our data revealed that despite the similar steroid levels in plasma and secreted in vitro by neonatal and adult heat-acclimated rat testicular slices, the molecular mechanisms underlying the steroidogenic response to heat acclimation during these different developmental stages were distinct.

Adaptation and Dysadaptation of Abuse-Independent Physiological Responses to Amphetamine

Although amphetamine (AMPH) is an addictive drug of abuse which exhibits toxicity to dopaminergic neurons in long-term abusers, AMPH shows some abuse-independent effects. AMPH increases dopamine (DA) release from striatum by enhancing cytosolic DA ＂via＂ the redistribution of neurotransmitters from synaptic vesicles to neuronal cytoplasm and the reverse transport of DA from cytoplasm to synapse ＂via＂ the dopamine transporter (DAT). AMPH competitively binds DAT by facilitating the exchange of cytosolic DA, and inhibits the monoamine oxidase to decreasing the metabolism of postsynaptic DA. AMPH locally applied in ventral tegmental area (VTA) enhances DA release in nucleus accumbens and medial prefrontal cortex by activating noradrenergic neurotransmission in VTA. DA levels in striatum can be enhanced by estradiol ＂via＂ an increase of DAT expression following the administration of AMPH. In male rat tests, AMPH inhibits the basal and human chorionic gonadotropin (hCG)-stimulated secretion of testosterone by increasing cyclic AMP production and decreasing the activities of calcium channel and steroidogenic enzymes. AMPH also inhibits gastric emptying and intestinal transit ＂via＂ a mechanism associated with the hypersecretion of endogenous cholecystokinin (CCK). The offspring of pregnant rats administrated with AMPH shows ventricular hypertrophy, systolic dysfunction, and apoptosis in cardiac muscles. The above findings indicate that AMPH demonstrates multiple effects on cardiac, endocrine and gastrointestinal systems. Both adaptation and dysadaptation of abuse-independent physiological responses to AMPH are highly suggested.

Amelioration of nandrolone decanoate-induced testicular and sperm toxicity in rats by taurine: Effects on steroidogenesis, redox and inflammatory cascades, and intrinsic apoptotic pathway

The wide abuse of the anabolic steroid nandrolone decanoate by athletes and adolescents for enhancement of sporting performance and physical appearance may be associated with testicular toxicity and infertility. On the other hand, taurine; a free β-amino acid with remarkable antioxidant activity, is used in taurine-enriched beverages to boost the muscular power of athletes. Therefore, the purpose of this study was to investigate the mechanisms of the possible protective effects of taurine on nandrolone decanoate-induced testicular and sperm toxicity in rats. To achieve this aim, male Wistar rats were randomly distributed into four groups and administered either vehicle, nandrolone decanoate (10mg/kg/week, I.M.), taurine (100mg/kg/day, p.o.) or combination of taurine and nandrolone decanoate, for 8successiveweeks. Results of the present study showed that taurine reversed nandrolone decanoate-induced perturbations in sperm characteristics, normalized serum testosterone level, and restored the activities of the key steroidogenic enzymes; 3β-HSD, and 17β-HSD. Moreover, taurine prevented nandrolone decanoate-induced testicular toxicity and DNA damage by virtue of its antioxidant, anti-inflammatory, and anti-apoptotic effects. This was evidenced by taurine-induced modulation of testicular LDH-x activity, redox markers (MDA, NO, GSH contents, and SOD activity), inflammatory indices (TNF-α, ICAM-1 levels, and MMP-9 gene expression), intrinsic apoptotic pathway (cytochrome c gene expression and caspase-3 content), and oxidative DNA damage markers (8-OHdG level and comet assay). In conclusion, at the biochemical and histological levels, taurine attenuated nandrolone decanoate-induced poor sperm quality and testicular toxicity in rats.

Transient effect of single dose exposure of Nigerian Bonny-light crude oil on testicular steroidogenesis in Wistar rats is accompanied by oxidative stress

The folkloric use of Nigerian Bonny-light crude oil (BLCO) in Niger Delta area of Nigeria is a common practice. There is increasing experimental evidence portending the adverse effects of BLCO an environmental toxicant on testicular function. We investigated the effects of single dose of BLCO (800 mg/kg body weight) on the activities of steroidogenic and antioxidant enzymes such as serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone, 3 β-hydroxy-steroid dehydrogenase (3 β-HSD), 17 β-hydroxy-steroid dehydrogenase (17 β-HSD), superoxide dismutase (SOD), glutathione-S-transferase (GST) and glutathione peroxidase (GSH-Px), levels of lipid peroxidation (LPO), glutathione reduced (GSH) and steroidogenic acute regulatory (StAR) protein, in testes of rats. There was a sequential reduction in the concentration of steroid hormones and activities of steroidogenic enzymes with a concomitant decrease in levels of StAR protein, followed by a parallel increase in antioxidant enzyme activities and levels of LPO. These findings revealed inhibitory effects of BLCO on testicular steroidogenesis and the possible role of oxidative stress in testicular dysfunction observed in this study.

Effects of Atrazine on Reproductive Health of Nondiabetic and Diabetic Male Rats.

The aim of the present study was to investigate the effects of low dose of atrazine on reproductive system of male Wistar rats. 16 rats were divided into four groups of four animals each. Group I (nondiabetic) and group III (diabetic) animals served as controls that received safflower oil (300 μL/kg bw/day), respectively. Group II (nondiabetic) and group IV (diabetic) animals received atrazine (300 μg/kg bw/day). Nonsignificant decrease in the activities of antioxidant and steroidogenic enzymes and sperm parameters suggests that atrazine did not produce any effect on reproductive system of rats. Histological findings also revealed that atrazine at a dose of 300 μg/kg bw did not produce any testicular toxic effects in nondiabetic and diabetic atrazine treated rats. Low dose of atrazine did not show reproductive toxicity in rats. To know the effects of atrazine in diabetic rats further studies have to be carried out with increased concentration of atrazine.

Validation of murine and human placental explant cultures for use in sex steroid and phase II conjugation toxicology studies

Human primary placental explant culture is well established for cytokine signaling and toxicity, but has not been validated for steroidogenic or metabolic toxicology. The technique has never been investigated in the mouse. We characterized human and mouse placental explants for up to 96h in culture. Explant viability (Lactate dehydrogenase) and sex steroid levels were measured in media using spectrophotometry and ELISA, respectively. Expression and activities of the steroidogenic (3β-hydroxysteroid dehydrogenase, Cytochrome P45017A1, Cytochrome P45019), conjugation (UDP-glucuronosyltransferase, sulfotransferase (SULT)), and regeneration (β-glucuronidase, arylsulfatase C (ASC)) enzymes were determined biochemically in tissues with fluorimetric and spectrophotometric assays, and western blot. Explants were viable up to 96h, but progesterone, estrone, and 17β-estradiol secretion decreased. Steroidogenic enzyme expression and activities were stable in mouse explants and similar to levels in freshly isolated tissues, but were lower in human explants than in fresh tissue (P<0.01). Human and mouse explants exhibited significantly less conjugation after 96h, SULT was not detected in the mouse, and neither explants had active ASC, although proteins were expressed. Mouse explants may be useful for steroid biochemistry and endocrine disruption studies, but not metabolic conjugation. In contrast, human explants may be useful for studying conjugation for <48h, but not for steroid/endocrine studies.

Curcumin and quercetin ameliorate cypermethrin and deltamethrin induced male sterility by upregulating activity of pituitary gonadal hormones and steroidogenic enzymes

The intake of dietary antioxidants (plant phenolics, flavonoids, carotenoids) is considered very important for human well being. Curcumin and quercetin are polyphenolic bioactive compounds imparting benefit to human health. The industrial revolution has resulted excessive use of pesticides/insectcides in agricultural practices household pest management. Synthetic pyrethroids are among the most widely used insecticides because of their high effectiveness against a wide range of insects, rapid biodegradation, low mammalian toxicity and target oriented mechanism of action. Cypermethrin (Cyp) and deltamethrin (Del) are common synthetic pyrethroid used in agriculture, forestry as well as in public and animal health programmes. The aim of study was to assess reproductive toxicity associated with cypermethrin and deltamethrin exposure and the possible protective effect of curcumin and quercetin. Forty two male Wistar rats were divided into seven groups of six rats each. Group I was taken as control, group II exposed to Cyp (2 mg/kg bw), group III Del (2 mg/kg bw), group IV Cyp +Del (2 mg/kg bw each), group V Cyp and Del treated with curcumin (100 mg/kg bw), group VI Cyp and Del treated with quercetin (100 mg/kg bw) and group VII Cyp and Del treated with quercetin+curcumin (100 mg/kg bw each) for 28 days. Cyp and Del administration caused decrease in reproductive organ weight, sperm count, sperm motility, steroidogenic enzymes (3-beta HSD and 17-beta HSD), reproductive hormones (T, LH, FSH), non-enzymatic (GSH) and enzymatic antioxidants (SOD, CAT, GPx, GR, GST) and increased in sperm abnormalities, and LPO. Single and combined treatment with curcumin and quercetin against these pesticide significantly altered the changes induced by pesticides. In conclusion, curcumin and quercetin are protective agent against cypermethrin and deltamethrin induced reproductive toxicity and oxidative stress damage in rats.

A mechanism for rapid neurosteroidal regulation of parenting behaviour

While systemic steroid hormones are known to regulate reproductive behaviour, the actual mechanisms of steroidal regulation remain largely unknown. Steroidogenic enzyme activity can rapidly modulate social behaviour by influencing neurosteroid production. In fish, the enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD) synthesizes 11-ketotestosterone (KT, a potent teleost androgen) and deactivates cortisol (the primary teleost glucocorticoid), and both of these steroid hormones can regulate behaviour. Here, we investigated the role of neurosteroidogenesis in regulating parenting in a haremic bidirectionally hermaphroditic fish, Lythrypnus dalli, where males provide all requisite parental care. Using an in vitro assay, we found that an 11β-HSD inhibitor, carbenoxolone (CBX), reduced brain and testicular KT synthesis by 90% or more. We modulated neurosteroid levels in parenting males via intracerebroventricular injection of CBX. Within only 20 min, CBX transiently eliminated parenting behaviour, but not other social behaviour, suggesting an enzymatic mechanism for rapid neurosteroidal regulation of parenting. Consistent with our proposed mechanism, elevating KT levels rescued parenting when paired with CBX, while cortisol alone did not affect parenting. Females paired with the experimental males opportunistically consumed unattended eggs, which reduced male reproductive success by 15%, but some females also exhibited parenting behaviour and these females had elevated brain KT. Brain KT levels appear to regulate the expression of parenting behaviour as a result of changes in neural 11β-HSD activity.

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and phytoestrogen genistein on the activity and the presence of steroidogenic enzyme proteins in cultured granulosa cells of pigs

Environmental estrogens such as dioxins (e.g. 2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD) and phytoestrogens (e.g. genistein; G) are known to influence endocrine and reproductive processes in humans and animals. Because living organisms are usually exposed to small, non toxic, doses of dioxins and phytoestrogens, the aims of the study were to determine the effects of small, environmentally relevant doses of TCDD (100pM) and/or genistein (500nM) on: (1) the activity of steroidogenic enzymes (cholesterol side-chain cleavage enzyme, P450scc; 3β-hydroxysteroid dehydrogenase, 3β-HSD and aromatase, P450arom) and (2) amount of protein of the enzymes in granulosa cells isolated from medium and large ovarian follicles of pigs. To determine the activity of the enzymes, the incubation medium was supplemented with specific steroid substrates (25-hydroxycholesterol; pregnenolone; testosterone) of particular steroidogenic enzymes (P450scc, 3β-HSD and P450arom, respectively). Subsequently, the production of progesterone (P450scc and 3β-HSD) or estradiol (P450arom) was compared in the presence and absence of the appropriate steroid precursor. Neither genistein nor genistein combined with TCDD affected activity of P450arom and relative amounts of steroidogenic enzyme proteins in the examined granulosa cells of pigs. In contrast, genistein alone and in combination with TCDD decreased P450scc and 3β-HSD activity as well as progesterone production in granulosa cells isolated from medium and large follicles of pigs. Because TCDD alone did not affect steroid hormone production or enzyme activity, the above effects should be ascribed solely to genistein. It appears that the effects of the examined doses of TCDD and genistein on granulosal cell functions were not additive.

Rooibos Flavonoids Inhibit the Activity of Key Adrenal Steroidogenic Enzymes, Modulating Steroid Hormone Levels in H295R Cells

Major rooibos flavonoids—dihydrochalcones, aspalathin and nothofagin, flavones—orientin and vitexin, and a flavonol, rutin, were investigated to determine their influence on the activity of adrenal steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (3βHSD2) and cytochrome P450 (P450) enzymes, P450 17α-hydroxylase/17,20-lyase (CYP17A1), P450 21-hydroxylase (CYP21A2) and P450 11β-hydroxylase (CYP11B1). All the flavonoids inhibited 3βHSD2 and CYP17A1 significantly, while the inhibition of downstream enzymes, CYP21A2 and CYP11B1, was both substrate and flavonoid specific. The dihydrochalcones inhibited the activity of CYP21A2, but not that of CYP11B1. Although rutin, orientin and vitexin inhibited deoxycortisol conversion by CYP11B1 significantly, inhibition of deoxycorticosterone was <20%. These three flavonoids were unable to inhibit CYP21A2, with negligible inhibition of deoxycortisol biosynthesis only. Rooibos inhibited substrate conversion by CYP17A1 and CYP21A2, while the inhibition of other enzyme activities was <20%. In H295R cells, rutin had the greatest inhibitory effect on steroid production upon forskolin stimulation, reducing total steroid output 2.3-fold, while no effect was detected under basal conditions. Nothofagin and vitexin had a greater inhibitory effect on overall steroid production compared to aspalathin and orientin, respectively. The latter compounds contain two hydroxyl groups on the B ring, while nothofagin and vitexin contain a single hydroxyl group. In addition, all of the flavonoids are glycosylated, albeit at different positions—dihydrochalcones at C3' and flavones at C8 on ring A, while rutin, a larger molecule, has a rutinosyl moiety at C3 on ring C. Structural differences regarding the number and position of hydroxyl and glucose moieties as well as structural flexibility could indicate different mechanisms by which these flavonoids influence the activity of adrenal steroidogenic enzymes.

Combined administration of curcumin and gallic acid inhibits gallic acid-induced suppression of steroidogenesis, sperm output, antioxidant defenses and inflammatory responsive genes

In this study, we investigated the effects of administration of gallic acid (Gal) with or without curcumin (Cur) on the sperm output, steroid level and antioxidant defenses in rat testis in vivo and the expression of inflammatory responsive genes in vitro. Male Wistar rats were divided randomly into four groups and given oral Gal (100mg/kg/day) and Cur (100mg/kg/day) alone or in combination for four weeks. The sperm quality was impaired following Gal treatment, while Cur prevented this and also improved the sperm count as well as the efficiency of sperm production (DSP/gm testis). The inhibitory effects of Gal on plasma testosterone level, glutathione levels, activities of glutathione peroxidase, catalase, superoxide dismutase and steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-HSD in the rat testis was blocked by Cur. Interestingly, the level of testosterone and the activities of the steroidogenic enzymes were significantly increased after treatment with Cur alone. Malondialdehyde concentration was unchanged following Gal treatment, while a significant decrease in malondialdehyde level was observed following treatment with Cur alone or in combination with Gal. We further analyzed the effects of Cur and Gal (25–100μM) on the 93RS2 Sertoli cell-lines and observed that Cur blocked the Gal-induced suppression of inflammatory mediators such as TNF-α and IL-6, while Gal blocked the suppressive effect of Cur on IL-1α expression. Furthermore, the stimulatory or inhibitory effects of Gal on the expressions Tgf-β1 and CD-14 was concentration-dependent and could be blocked by Cur. When cultures of primary Sertoli cells were exposed to both Cur and Gal for 24h, p-JNK/SAPK expression remain stable, whereas Gal-induced p-p65 (NF-κB) expression and IκBα degradation was seen to be blocked by Cur but not Gal-induced expression of pERK1/2. Overall, Cur has stimulatory reproductive effects and could protect the testis from the toxic effects of Gal by mechanisms that could not be explained by its effects on the expressions of inflammatory cytokines but by its anti-oxidant properties.

Insulin-Like Factor 3 and the HPG Axis in the Male

The hypothalamic–pituitary–gonadal (HPG) axis comprises pulsatile GnRH from the hypothalamus impacting on the anterior pituitary to induce expression and release of both LH and FSH into the circulation. These in turn stimulate receptors on testicular Leydig and Sertoli cells, respectively, to promote steroidogenesis and spermatogenesis. Both Leydig and Sertoli cells exhibit negative feedback to the pituitary and/or hypothalamus via their products testosterone and inhibin B, respectively, thereby allowing tight regulation of the HPG axis. In particular, LH exerts both acute control on Leydig cells by influencing steroidogenic enzyme activity, as well as chronic control by impacting on Leydig cell differentiation and gene expression. Insulin-like peptide 3 (INSL3) represents an additional and different endpoint of the HPG axis. This Leydig cell hormone interacts with specific receptors, called RXFP2, on Leydig cells themselves to modulate steroidogenesis, and on male germ cells, probably to synergize with androgen-dependent Sertoli cell products to support spermatogenesis. Unlike testosterone, INSL3 is not acutely regulated by the HPG axis, but is a constitutive product of Leydig cells, which reflects their number and/or differentiation status and their ability therefore to produce various factors including steroids, together this is referred to as Leydig cell functional capacity. Because INSL3 is not subject to the acute episodic fluctuations inherent in the HPG axis itself, it serves as an excellent marker for Leydig cell differentiation and functional capacity, as in puberty, or in monitoring the treatment of hypogonadal patients, and at the same time buffering the HPG output.

Biotransformation of dihydroisosteviol and the effects of transformed products on steroidogenic gene expressions

The biotransformation of dihydroisosteviol with Absidia pseudocylindrospora ATCC 24169, Streptomyces griseus ATCC 10137, Mucor recurvatus MR36, and Aspergillus niger BCRC 31130 yielded 15 metabolites, eight of which were previously unknown. Structures of metabolites were established by 2D NMR techniques and HRMS data, two of which were further corroborated by chemical means, and another via single-crystal X-ray diffraction analysis. Subsequently, two steroidogenic cell lines (Y-1 mouse adrenal tumor and MA-10 mouse Leydig tumor cells) were used in a reverse transcription-PCR analysis to assess the effects of all compounds on steroidogenic gene expressions using forskolin as a positive control. The tested gene expressions included steroidogenic factor-1 (SF-1), steroidogenic acute regulatory protein (StAR), and cytochrome P450 side-chain cleavage (P450scc) enzyme. Gene expression profiles showed that ten of the tested compounds effectively suppressed P450SCC mRNA expression in both Y-1 and MA-10 cells. Several induced SF-1 gene expression and two enhanced StAR gene expression in Y-1 cells. By contrast, in MA-10 cells, one compound effectively suppressed StAR mRNA expression, whereas for others effectively suppressed SF-1 gene expression. The results suggest that analogs of dihydroisosteviol can be potential modulators to alter steroidogenic gene expressions and subsequent enzyme activities.

Kolaviron prevents carbendazim-induced steroidogenic dysfunction and apoptosis in testes of rats

The study evaluated the protective role of kolaviron (an isolated biflavonoid from the seed of Garcinia kola) and vitamin E in carbendazim-induced reproductive dysfunction in male rats. Adult male Wistar rats were orally exposed to carbendazim (200mg/kg) singly or in combination with kolaviron (100 and 200mg/kg). Exposure to carbendazim significantly decreased the activities of superoxide dismutase and catalase but markedly increased sialic acid concentration and lipid peroxidation in the testes of rats. Western blot analysis revealed that carbendazim treatment decreased the expression of steroid acute regulatory (StAR) protein and androgen binding protein (ABP) with concomitant decrease in activities of steroidogenic enzymes. Germ cell apoptosis in carbendazim-treated rats was confirmed by TUNEL assay. However, pretreatment with kolaviron and vitamin E restored the testicular antioxidant status and steroidogenesis and decreased apoptotic nuclei to near control level in carbendazim-treated rats. Kolaviron may prove useful in combating carbendazim-induced reproductive toxicity.

The effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin and genistein on the activity of steroidogenic enzymes in porcine granulosa cells

The effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin and genistein on the activity of steroidogenic enzymes in porcine granulosa cells

TCDD and corticosterone on testicular steroidogenesis and antioxidant system of epididymal sperm in rats

2,3,7,8-Tetrachloro dibenzo-p-dioxin (TCDD), an endocrine-disrupting environmental pollutant, has been found to cause male reproductive toxicity. Glucocorticoids have been found to influence the metabolic pathway of TCDD. Stress, which affects the male reproductive function, is marked by an increase in the level and activity of glucocorticoids in the body. The present study was carried out to understand the effect of TCDD on testicular steroidogenesis and sperm antioxidant system under the influence of increased level of corticosterone in the body. Adult male rats were treated with either TCDD (100 ng/kg bw/ day) or corticosterone (3mg/kgbw/day) or both for 15days. Treatment with either TCDD or corticosterone was found to suppress the levels of steroidogenic acute regulatory protein and androgen-binding protein and reduce the activities of steroidogenic enzymes in testis while increasing oxidative stress in ventral prostate, seminal vesicles and epididymal sperm. In rats treated with both TCDD and corticosterone, the suppression of testicular steroidogenesis and increase in oxidative stress observed in ventral prostate, seminal vesicles and epididymal sperm were significant as compared to TCDD alone treated rats. The levels of Fas and FasL proteins were also increased in rats subjected to either TCDD or corticosterone treatment. In rats treated with both compounds, the increase observed in testicular levels of Fas and FasL was significant as compared to TCDD alone treated rats. Effect of TCDD on testicular steroidogenesis and antioxidant system of epididymal sperm may get enhanced under increased level of glucocorticoids in the body.

Medical Treatment of Cushing's Disease

Cushing's disease (CD) is associated with serious morbidity and, when suboptimally treated, an increased mortality. Although surgery is the first-line treatment modality for CD, hypercortisolism persists or recurs in an important subset of patients. Considering the deleterious effects of uncontrolled CD, there is a clear need for effective medical therapy. In this review, we discuss molecular targets for medical therapy, efficacy, and side effects of the currently used drugs to treat hypercortisolism and focus on recent developments resulting from translational and clinical studies. Selection of publications related to the study objective was performed via a PubMed search using relevant keywords and search terms. Medical therapy for CD can be classified into pituitary-directed, adrenal-blocking, and glucocorticoid receptor-antagonizing drugs. Recent studies demonstrate that somatostatin receptor subtype 5 (sst(5)) and dopamine receptor subtype 2 (D(2)) are frequently (co-)expressed by corticotroph adenomas. Pituitary-directed therapy with pasireotide and cabergoline, targeting sst(5) and D(2), respectively, is successful in approximately 25-30% of patients. Adrenal-blocking drugs can be effective by inhibiting steroidogenic enzyme activity. Finally, the glucocorticoid receptor antagonist mifepristone induces clinical and metabolic improvement in the majority of patients. Each drug can have important side effects that may impair long-term treatment. Generally, patients with moderate to severe hypercortisolism need combination therapy to normalize cortisol production. Medical therapy for CD can be targeted at different levels and should be tailored in each individual patient. Future studies should examine the optimal dose and combination of medical treatment modalities for CD.

Acute effects of hexabromocyclododecane on Leydig cell cyclic nucleotide signaling and steroidogenesis in vitro

Hexabromocyclododecane (HBCDD), an additive brominated flame retardant routinely added to various consumer products, was reported to have toxic effects upon biota, including endocrine disruption. In this study, the potential toxicity of HBCDD was tested in peripubertal rat Leydig cells in vitro during 6h exposure. HBCDD inhibited human chorionic gonadotropin- and forskolin-supported cAMP accumulation and steroidogenesis. It also inhibited basal cAMP production, but elevated basal steroidogenesis. The expression of several cAMP-dependent genes, including steroidogenic acute regulatory protein, cholesterol side chain cleavage enzyme, and 3β-hydroxysteroid dehydrogenase, was also inhibited by HBCDD treatment. Nevertheless, this was not accompanied by a decrease in steroidogenic acute regulatory protein expression, as documented by western blot analysis, and activity of steroidogenic enzymes, as documented by unaffected steroidogenesis in the presence of permeable 22(R)-hydroxycholesterol. However, HBCDD caused significant decrease in mitochondrial membrane potential in untreated and human chorionic gonadotropin-treated cells. This indicates that HBCDD acute toxicity in Leydig cells reflects changes in mitochondrial membrane potential-dependent cAMP production and basal and cAMP-regulated cholesterol transport. This in turn facilitates basal but inhibits cAMP-dependent steroidogenesis. Acute effects of HBCDD treatment on transcription are also indicative of its sustained effects on Leydig cell function.