Rapid Screening of Glucocorticoid Receptor (GR) Effectors Using Cortisol-Detecting Sensor Cells.

Cortisol, a stress hormone, plays key roles in mediating stress and anti-inflammatory responses. As abnormal cortisol levels can induce various adverse effects, screening cortisol and cortisol analogues is important for monitoring stress levels and for identifying drug candidates. A novel cell-based sensing system was adopted for rapid screening of cortisol and its functional analogues under complex cellular regulation. We used glucocorticoid receptor (GR) fused to a split intein which reconstituted with the counterpart to trigger conditional protein splicing (CPS) in the presence of targets. CPS generates functional signal peptides which promptly translocate the fluorescent cargo. The sensor cells exhibited exceptional performance in discriminating between the functional and structural analogues of cortisol with improved sensitivity. Essential oil extracts with stress relief activity were screened using the sensor cells to identify GR effectors. The sensor cells responded to peppermint oil, and L-limonene and L-menthol were identified as potential GR effectors from the major components of peppermint oil. Further analysis indicated L-limonene as a selective GR agonist (SEGRA) which is a potential anti-inflammatory agent as it attenuates proinflammatory responses without causing notable adverse effects of GR agonists.

Attenuation of the cyproterone acetate-induced testicular hypofunction by a novel nutraceutical lycopene: a genomic approach.

This study was designed to explore the cyproterone acetate (CPA)-induced andrological hypofunction and its correction by oral administration of lycopene. In this concern, spermatogenic, biochemical, histological and genomic profiles were studied. Cyproterone acetate administration for 1 month helped to develop infertile model rats. A significant recovery was noted in sperm motility, sperm count, sperm viability, hypo-osmotic swelling tail-coiled spermatozoa; activities of testicular ∆5 , 3ß-hydroxysteroid dehydrogenase (HSD), 17ß-HSD, catalase (CAT) and superoxide dismutase (SOD); and levels of conjugated diene (CD), malondialdehyde (MDA), testicular cholesterol and serum testosterone after the administration of lycopene at 1.5 mg/0.5 ml Tween-80/100 g body weight/day for last 1 month to infertile model rats. Simultaneously, qRT-PCR study of Bax, Bcl-2, caspase-3, ∆5 , 3ß-HSD and 17ß-HSD genes in testicular tissue showed a significant rectification towards the control in CPA-pre-treated cum CPA-lycopene-cotreated rats. Side-by-side histological and histometric studies showed a significant correction in qualitative analysis of spermatogenesis and seminiferous tubular diameter (STD) in CPA-pre-treated cum CPA-lycopene-cotreated rats. Lycopene showed outstanding efficacy in the management of CPA-induced testicular hypofunction with special reference to correction in oxidative stress-induced testicular apoptosis at genomic level.

Efficacy of echinacea on the action of cyproterone acetate in male rats.

The study aimed to evaluate the effect Echinacea extract (E) on the testicular antioxidants function in normal rats or that subjected to anti-androgenic compound, cyproterone acetate (CA). Rats were divided into 5 groups treated daily via an oral tube for two intervals 2 and 4 weeks, 1st control, 2nd E (Echinacea treated group in dose 63 mg kg(-1)), 3rd CA (cyproterone acetate treated group in dose 25 mg kg(-1)), 4th E+CA and 5th E as prophylactic one week before E+CA treatment with the same aforementioned E or CA doses. The body, testes, epididymis and vas deferens weights were recorded. Sperm count, Nitric Oxide (NO), calcium ion (Ca2+) and malondialdhyde (MDA) contents in addition to superoxide dismutase (SOD), glutathione S-transferase (GST) activities were determined in testicular tissues. CA exhibited direct negative effect on reproductive organs weight and significant reducing effect on sperm count and Ca2+ contents. SOD and GST activities significantly decreased in addition to significant increase in NO, MDA contents reflecting the oxidative status of testis in CA treated rats. The prophylactic effect of E treatment, in time related manner, showed significant improvement in the antioxidant status of the testicular tissue which is more pronounced as compared to E+CA treatment.

Evaluation of a 15-day screening assay using intact male rats for identifying antiandrogens.

An in vivo screening assay using intact adult male rats has been evaluated for its ability to detect six antiandrogenic compounds via oral administration. The test compounds included cyproterone acetate (CPA), flutamide (FLUT), p,p'-DDE (DDE), di-n-butyl phthalate (DBP), linuron (LIN), and vinclozolin (VCZ). Two of the test compounds (DDE and FLUT) have been previously evaluated in the 15-day intact male assay with compound administration via intraperitoneal injection (ip). For the current studies, male rats were dosed for 15 days via oral gavage and euthanized on the morning of test day 15. The endpoints evaluated included final body and organ weights (liver, thyroid gland, testes, epididymides, prostate, seminal vesicles with fluid, accessory sex gland unit [ASG]), serum hormone concentrations (testosterone [T], estradiol [E2], dihydrotestosterone [DHT], luteinizing hormone [LH], follicle stimulating hormone [FSH], prolactin [PRL], T(3), T(4), and thyroid stimulating hormone[TSH]), and histopathology of the testis, epididymis, and thyroid gland; positive results for each endpoint are described below. In addition, an evaluation of immune system endpoints (humoral immune function, spleen and thymus weights, and spleen cell number) was conducted on a subset of animals dosed with either DDE or FLUT. All six endocrine-active compounds (EACs) increased relative liver weight. FLUT and VCZ caused the typical pattern for an androgen receptor (AR) antagonist, although not all endpoints were statistically significant for VCZ: decreased ASG weights, hormonal alterations (increased T, DHT, LH, and FSH), and induced Leydig cell hypertrophy and/or hyperplasia. CPA caused effects consistent with its mixed AR antagonist/progesterone receptor agonist activity: it decreased ASG weights, caused hormonal alterations (increased T and E2; decreased FSH), and caused spermatid retention. DBP, a compound with antiandrogen-like activity via a nonreceptor mediated mechanism, caused hormonal alterations (decreased T, DHT, and E2; increased LH, FSH, and PRL) and induced general testicular degeneration. LIN, a weak AR antagonist, decreased ASG weights, caused hormonal alterations (decreased T, DHT, and LH; increased E2), and caused spermatid retention. Unlike the other AR antagonists evaluated, DDE, a weak AR antagonist, did not alter reproductive parameters. All six antiandrogens caused some effects on thyroid parameters, although only CPA, DDE, and VCZ caused results consistent with a potential thyroid-modulator. FLUT and DDE did not alter the primary humoral immune response to SRBC, spleen or thymus weights, or spleen cell number. In the current study, 5 of the six test substances were identified as endocrine-active substances consistent with their known/proposed mechanism(s) of action. The effects that were observed in the current study via oral (gavage) compound administration were similar to the responses that were observed by the ip route in previous studies for DDE and FLUT. This report, in addition to the > 20 compounds that have already been examined using the 15-day intact male assay, supports this assay as a viable screening assay for detecting EACs, and also illustrates that the ability to identify EACs using the intact male assay will be equivalent regardless of the route of compound administration.

Rapid androgen actions on calcium signaling in rat sertoli cells and two human prostatic cell lines: similar biphasic responses between 1 picomolar and 100 nanomolar concentrations.

Androgen-induced calcium fluxes and gap junctional intercellular communication (GJIC) were studied in three different cell types. A transient (2-3 min duration) increase in intracellular calcium levels was observed within 20-30 sec of androgen addition, which was followed by a plateau phase with steroid concentrations higher than 1 nM. The kinetics of the calcium responses were similar in immature rat Sertoli cells, which contain normal nuclear receptors; the human prostatic tumor cell line, LNCaP, which contains a mutated nuclear receptor; and the human prostatic cell line, PC3, which does not contain a nuclear receptor. The human A431 tumor cell line did not respond to androgens. Concentrations of testosterone and the synthetic androgen, R1881, between 1-1000 pM induced transient calcium increases with ED(50) values near 1 pM and 1 nM, whereas dihydrotestosterone (DHT) was not active at these concentrations. At concentrations higher than 1 nM, testosterone, R1881, and DHT were equipotent in stimulating an increase in calcium that lasted for more than 10 min, with ED(50) values between 5 and 20 nM. Testosterone covalently bound to albumin was also active, whereas 11 related androstane compounds as well as progesterone and estradiol-17beta were inactive at 1000 nM. The calcium response induced by the three androgens (10 nM) was abolished in all cell types by hydroxyflutamide (1000 nM) and finasteride (1000 nM), but not by cyproterone acetate (1000 nM). The calcium response was also abolished in the absence of extracellular calcium and strongly inhibited by the presence of verapamil. Exposure of the responsive cells to brief (150-sec) pulses of androgens generated calcium responses that were similar to those after continuous exposure. After exposure of Sertoli cells for only 30 sec to 100 nM testosterone, the calcium response lasted for at least 50 min. Although nuclear binding of androgens could be demonstrated, there was no evidence for tight binding to the plasma membrane under similar conditions. When protein synthesis was inhibited, an enhancement of GJIC between rat Sertoli cells, but not between LNCaP cells or PC3 cells, was observed within 15 min of the addition of 10 nM testosterone. Because nuclear androgens are not present in PC3 cells and many functional properties of the responsive system are different from the nuclear receptor in all three cell types, we postulate the existence of an alternative cell surface receptor system with biphasic response characteristics (high and low affinity). The calcium signals are probably coupled to the regulation of gap junctional efficiency between Sertoli cells. The low-affinity receptors may convey complementary androgen signals at elevated local levels such as in the testis, when nuclear receptors are (over)saturated.

Hyperglycemic effect of a neurotoxic fraction (F3) from Naja haje venom: role of hypothalamo-pituitary adrenal axis (HPA).

The effect of bolus intravenous injection of sub-LD50 (35 micrograms Kg-1) of the neurotoxic fraction (F3) of the Egyptian cobra Naja haje on the plasma level of ACTH and serum levels of cortisol, insulin, glucose, total lipids, triacylglycerols, free fatty acids, total cholesterol, HDL and LDL-cholesterol, and glycogen content of liver and kidneys were studied in rabbit pretreated with cyproteron acetate (CA) or saline solution and propylene glycol (PG) to elucidate the possible role of the hypothalamo-pituitary adrenal (HPA) axis in the venom fraction-induced hyperglycemia. F3 increased cortisol and insulin level in both groups, whereas ACTH was found to decrease subsequent to the treatment. Serum glucose level was elevated by F3 treatment and this effect was substantiated in CA-treated rabbits. This hyperglycemia was concomitant with a decline in glycogen content of the liver and kidneys. A decline in serum total lipids, triacylglycerols, and free fatty acids was observed following F3 treatment, and this effect was intensified by CA-pretreatment. These data suggest that F3 stimulates glucocorticoid release from adrenocortical cells which, in turn, may modulate both insulin and glucose turnover to maintain hyperglycemia during stress period. The possible underlying mechanisms were discussed.

Developmental expression and regulation of aromatase- and 5alpha-reductase type I mRNA in the male and female mouse hypothalamus.

Androgen metabolites synthesized by neural aromatase and 5alpha-reductase are implicated in many aspects of mammalian brain development and, in particular, in the masculinization of distinct central nervous system structures and brain functions. The present study was designed to determine (1) the developmental profile of aromatase- and 5alpha-reductase type I mRNA expression in the mouse hypothalamus and (2) to relate ontogenetic sex differences in aromatase activity which have been described in the past to sex-specific aromatase gene expression. In addition, we analysed the effect of androgens on the perinatal regulation of hypothalamic aromatase and 5alpha-reductase type I mRNA expression. By applying semiquantitative reverse transcription-polymerase chain reaction analysis, we found hypothalamic aromatase mRNA expression to be developmentally regulated and to display sex differences at birth and on postnatal day 15 with higher mRNA levels in males. Newborn males and females, which were treated in utero with the androgen receptor antagonist cyproterone actetate, exhibited significantly reduced aromatase mRNA levels compared with untreated controls. In contrast to aromatase, expression levels of hypothalamic 5alpha-reductase mRNA did not reveal a clear-cut developmental profile or sex differences, and no regulatory role for androgens in controlling 5alpha-reductase mRNA expression was found. In conclusion, these results demonstrate perinatal sex differences in hypothalamic aromatase- but not 5alpha-reductase gene expression and suggest that sex differences in perinatal aromatase activity are reflected by corresponding differences in mRNA levels. Androgens are found to control brain estrogen formation pretranslationally at the level of aromatase gene expression. Our findings imply that sex differences in androgen availability and responsiveness are important regulatory factors for aromatase expression in the developing male hypothalamus.

Effects of gonadal androgens and oestrogens on adrenal androgen levels.

OBJECTIVE: The physiological role of adrenal androgens in humans remains unclear. Furthermore, there are few data on the relation between sex steroids and adrenal androgen production. We have assessed the effects of sex steroid hormone administration on adrenal androgen levels, by studying a large group of transsexual patients. DESIGN: A non-randomized intervention. SETTING: A university teaching hospital. PATIENTS: Thirty-one male-to-female and 22 female-to-male transsexual patients. MEASUREMENTS: Plasma levels of adrenal androgens were measured in a group of male-to-female and female-to-male transsexual patients both before and during cross-gender hormone treatment. This treatment involves administration of testosterone esters to women and of ethinyloestradiol and cyproterone acetate to men. RESULTS: High dose sex steroid administration had marked effects on adrenal androgens levels, which decreased by 27-48% in males treated with ethinyloestradiol and increased by 23-70% in females treated with testosterone. CONCLUSION: We conclude that administration of high doses of testosterone and oestradiol exert opposing effects on adrenal androgen production.

Androgens increase intracellular calcium concentration and inositol 1,4,5-trisphosphate and diacylglycerol formation via a pertussis toxin-sensitive G-protein.

Bone is a target tissue of androgens, but the mechanisms by which they act on bone are still unclear. This study examines the early (5-60 s) effects of 1 pM to 1 microM testosterone on cytosolic free Ca2+ concentration ([Ca2+]i) and inositol 1,4,5-trisphosphate (InsP3) and diacyglycerol (DAG) formation in confluent male rat osteoblasts. 10 pM to 10 nM testosterone increased [Ca2+]i within 5 s via Ca2+ influx as shown by the effects of EGTA and the Ca2+ channel blockers nifedipine and verapamil and via Ca2+ mobilization from the endoplasmic reticulum as shown by the effects of thapsigargin and neomycin. 10 pM to 10 nM testosterone increased InsP3 and DAG formation within 10 s. Testosterone immobilized on bovine serum albumin (testosterone (O-carboxymethyl)oxime/bovine serum albumin) and its derivative, (O-carboxymethyl)oxime, rapidly increased [Ca2+]i and InsP3 and DAG formation and were full agonists, although they were less potent than the free steroid. Cyproterone acetate, a nuclear antagonist, did not block the increase in [Ca2+]i and InsP3 and DAG formation induced by testosterone. Finally, neomycin and pertussis toxin totally abolished the effects of testosterone on InsP3 and DAG. These results suggest that male rat osteoblasts bear nongenomic unconventional cell-surface receptors for testosterone that belong to the class of the membrane receptors coupled to a phospholipase C via a pertussis toxin-sensitive G-protein.

Ontogeny, circadian rhythm pattern, and hormonal modulation of 5 alpha-dihydrotestosterone receptors in the rat pineal.

Some physiological parameters of pineal 5 alpha-dihydrotestosterone receptor in the rat such as ontogeny, circadian rhythm pattern, and its modulation by various neuropeptides and neurotransmitters which have profound influences on the pineal hormone melatonin were examined. Pineal 5 alpha-dihydrotestosterone receptors measured at different ages of the animal revealed that on day 10 both cytosolic receptor (CR) and nuclear receptor (NR) levels were high. With growth and development both groups of receptors declined and during puberty started again to rise. During adulthood both receptors were high; however, NR rose further with full maturation. Both groups of receptors showed circadian rhythmicity. While the CR was significantly higher at 6.00 h than at any time point through 24 h, the NR peaked at 18.00 h when the difference between both groups was maximum. Castration caused significant increment of NR. Treatment of castrated animals with a low dose of testosterone propionate (0.25 mg) significantly stimulated both receptor groups, while treatment with a high dose (2.5 mg) failed to do so. Treatment with various substances such as antiandrogen, opioids, neuropeptides, and neurotransmitters significantly modulated the pineal androgen receptor population: cyproterone acetate and monosodium glutamate suppressed CR; growth hormone releasing hormone increased NR; growth hormone release inhibiting hormone had no significant effects on either group of receptors; exogenous melatonin and norepinephrine increased NR; beta-endorphin increased only NR, but methionine enkephalin stimulated both, and epithalamine had no significant effects on either group of receptors, but thymosin alpha 1 increased NR.(ABSTRACT TRUNCATED AT 250 WORDS)