Effects of Eurycoma longifolia Jack on sexual qualities in middle aged male rats

The effects of Eurycoma longifolia Jack were studied on the sexual qualities of middle aged male rats after dosing them with 0.5 g/kg of various fractions of E. longifolia whilst the control group received 3 ml/kg of normal saline daily for 12 weeks. Results showed than E. longifolia Jack enhanced the sexual qualities of the middle aged male rats by decreasing their hesitation time as compared to controls with various fractions of E. longifolia Jack produced 865-916 (91-96), 860-914 (92-98), 850-904 (93-99), 854-890 (95-99), 844-880 (94-98), 840-875 (94-98), 830-870 (94-98), 825-860 (94-98), 820-850 (96-99), 800-840 (93-98), 750-795 (94-99) and 650-754 sec (82-95%) in contrast to controls which produced 950 (100), 934 (100), 910 (100), 900 (100), 895 (100), 890 (100), 885 (100), 880 (100), 855 (100), 860 (100), 800 (100) and 790 sec (100%) throughout the investigation period. Besides these, there was a transient increase in the % of the male rats responding to the right choice after chronic administration of 0.5 g/kg E. longifolia Jack, with more than 50% of the male rats scored right choice after 2 weeks post-treatment and the effect was more prominent at the dose of the observation period. However, there was no sexual enhancement of the middle aged male rats which consumed normal saline since only 45-55% of the male rats responded to right choice throughout the investigation period. Hence, this study shows that E. longifolia Jack enhanced the sexual qualities of the middle aged male rats, further supports the folkuse of E. longifolia Jack as an aphrodisiac.     

Effects of dihydrotestosterone and estradiol benzoate pretreatment upon testosterone-induced sexual behavior in the castrated male rat

Three groups of inexperienced castrated male rats were treated daily for 15 days with oil, estradiol benzoate (1 μg), or dihydrotestosterone (1 mg), and thereafter injected daily with testosterone (1 mg) for 21 days. Sexual behavior was tested every third day after the start of the pretreatment until day 36. Estradiol benzoate or dihydrotestosterone failed to elicit sexual behavior. Pretreatment with dihydrotestosterone, but not estradiol benzoate, significantly shortened the intervals to initiation of mounting and intromission in response to testosterone. The results suggest that fully developed genitals (penis and/or sexual accessories) facilitate initiation of copulatory behavior in response to testosterone administration.     

Évaluation des effets prosexuels des extraits de Bridelia ferruginea chez le rat mâle naïf

The stem barks and the leaves from Bridelia ferruginea (BF, Euphorbiaceae), a medicinal plant, are used in traditional medicine for the treatment of several ailments including male impotency. The present study was aimed at investigating the effects of the dried stem bark of BF on the sexual behaviour of normal and castrated sexually inexperienced male Wistar rats. Animals were orally administered with 100 mg/kg of either the aqueous or the ethanol extracts of BF whilst the neutral control group received in the same way 10 ml/kg of distilled water. The positive control group was treated with a subcutaneous injection of testosterone propionate (20 mg/kg/day/3days) prior to the experiment. The sexual behaviour of all rats was monitored on days 0, 1 and 7 by measuring frequencies of penile erection, mount, intromission and ejaculation. In a separate group of normal sexually inexperienced rats, the pro-sexual effects induced by a single dose of the aqueous extract (100 mg/kg) were measured after pre-treatment with either haloperidol (10 mg/kg), atropine (10 mg/kg) or L-omega-nitro-arginine methyl ester (Lω-NAME, 10 mg/kg). Results obtained showed a significant influence of the duration of treatment on the frequencies of penile erection, mount and intromission of both normal and castrated rats. An increase in all sexual performance parameters was observed when compared to respective controls. The intromission frequency of normal animals was significantly increased (P < 0.05–0.01) on day 1 of treatment and the effect was more expressed in rats receiving the aqueous extract. In castrated animals, a statistical increase was noticed on day 7 for rats treated with testosterone. The sexual effects induced by the aqueous extract of BF were completely abolished after pre-treatment of rats with atropine or haloperidol while pre-administration of Lω-NAME did not produce any significant effects. Flavonoids and sterols revealed in the aqueous and ethanolic extracts from the barks of BF may account for the enhancement of sexual activity in naive rats which could be expressed through dopaminergic and/or cholinergic receptor(s). Results of this work also give value to the traditional use of the plant for the improvement of male sexual behaviour.     

Uterotropic action of indomethacin on the rat uterus

Administration of indomethacin (10 mg/kg body weight, twice daily for 6 days) resulted in a significant (P less than 0.01) increase in the weight, and cross-sectional area of uteri of ovariectomized rats, whereas no such effects were observed following indomethacin administration to normal cycling rats. Prostaglandin F2 alpha (PGF2 alpha) content (ng/uterus) and concentration (ng/g wet weight) in the uterus of indomethacin-treated animals were reduced 40.4% and 60.8%. Simultaneous administration of either estradiol-17 beta (E2), progesterone testosterone with indomethacin to ovariectomized rats failed to reduce the uterine weight increase. On the contrary, concomitant administration of E2 (25 or 100 ng/day) and indomethacin resulted in uterine weight increases which were greater than those associated with indomethacin alone. Uterine E2 content was significantly higher in animals treated with indomethacin plus E2 as compared to those given estradiol alone. Uterine uptake of 2,4,6,7-[3H]E2 following i.v. administration was greater in animals pretreated with indomethacin (5 mg/kg, twice daily) for 3 days than in ovariectomized controls. These results suggest that prostaglandins may be involved in the regulation of uterine growth.     

Aphrodisiac properties of Tribulus Terrestris extract (Protodioscin) in normal and castrated rats

Tribulus terrestris (TT) has long been used in the traditional Chinese and Indian systems of medicine for the treatment of various ailments and is popularly claimed to improve sexual functions in man. Sexual behaviour and intracavernous pressure (ICP) were studied in both normal and castrated rats to further understand the role of TT containing protodioscin (PTN) as an aphrodisiac. Adult Sprague-Dawley rats were divided into five groups of 8 each that included distilled water treated (normal and castrated), testosterone treated (normal and castrated, 10 mg/kg body weight, subcutaneously, bi-weekly) and TT treated (castrated, 5 mg/kg body weight, orally once daily). Decreases in body weight, prostate weight and ICP were observed among the castrated groups of rats compared to the intact group. There was an overall reduction in the sexual behaviour parameters in the castrated groups of rats as reflected by decrease in mount and intromission frequencies (MF and IF) and increase in mount, intromission, ejaculation latencies (ML, IL, EL) as well as post-ejaculatory interval (PEI). Compared to the castrated control, treatment of castrated rats (with either testosterone or TT extract) showed increase in prostate weight and ICP that were statistically significant. There was also a mild to moderate improvement of the sexual behaviour parameters as evidenced by increase in MF and IF; decrease in ML, IL and PEI. These results were statistically significant. It is concluded that TT extract appears to possess aphrodisiac activity probably due to androgen increasing property of TT (observed in our earlier study on primates).     

The role of the pituitary in modifications of the uterine secretion of spayed, oestradiol-primed rats

Tests performed on spayed, adult female estradiol-primed Ivanovas rats, with ligated uteri and normal pituitary function have shown that treatment with sexual steroids, including progesterone and testosterone, modifies uterine secretion. One half of the animals were hypophysectomized. In estradiol primed hypophysectomized controls, growth was retarded about 28%, the weight of the empty uterus reduced, and the quantity of uterine secretion diminished in comparison with the values for the nonhypophysectomized controls. In test rats treated with estradiol, gain in body weight was virtually arrested in the nonhypophysectomized rats and a reduction in weight was observed in both groups treated with the highest dose of estradiol tested (300 mcg/kg daily). In rats treated with progesterone, no significant differences were found between the two groups. In treated groups, a dose-related reduction in the weight of the empty uterus was found. Treatment caused a marked reduction in the quantity of the uterine secretion, the effect appearing greater in nonhypophysectomized rats. Increasing doses of progesterone produced a rapid rise in the viscosity of the uterine fluid, as well as a decrease in the pH of the uterine lumen. In both hypophysectomized and nonhypophysectomized rats, testosterone induced a dose-related increase in body weight, statistically significant only in animals with intact pituitaries treated with 100 mg/kg daily. The weight of the empty uterus also increased. The quantity of uterine fluid was reduced by testosterone only when it was given in massive doses to nonhypophysectomized rats. Doses of 100-300 mg/kg daily were needed to produce the same response as a dose of about 10 mg/kg daily of progesterone. In response to large doses, viscosity of secretion rose slightly and the pH of uterine lumen and secretion decreased. It may be concluded that the progestative modifications induced by progesterone in the uterus of spayed, estradiol-primed rats, including particularly changes in uterine secretion, are the effects of a peripheral mechanism not involving the pituitary. Testosterone appears to be an exception as far as the quantity and viscosity of uterine secretion are concerned, since modifications in these parameters are only observed in the presence of a functional pituitary body.     

The ameliorative effects of Eurycoma longifolia Jack on testosterone-induced reproductive disorders in female rats

The objective of this research was to study the ameliorative effects of a standardized quassinoid-rich extract (TAF 273) of Eurycoma longifolia root on some reproductive disorders in female rats. An irregular estrous cycle and ovarian cystic follicles were induced in 21-day-old females by the daily administration of testosterone (10 mg/kg, sc) for three weeks. The hormone-treated rats exhibited persistent diestrous as well as ovaries containing cystic follicles. Upon treatment with TAF 273, fewer animals showed irregular estrous cycles and there was less follicular morphological damage. The reversal effect may be derived from the anti-estrogenic properties of the plant quassinoids.     

The Inflammatory Potential of Dietary Manganese in a Cohort of Elderly Men

In the current study, 48 male rats were classified into four groups (12 rats/group): 1—control group received 1 ml distilled water, 2—origanum oil group treated daily with oral dose of origanum oil (5 mg/kg) for 30 and 60 days, 3—mercuric chloride group treated daily with oral dose of mercuric chloride (4 mg/kg) for 30 and 60 days, and 4—origanum oil + mercuric chloride group treated with both origanum oil and mercuric chloride (5 and 4 mg/kg, respectively) for 30 and 60 days. All treatments were carried out by stomach tube. The results showed that administration of mercuric chloride induced significant increase in thiobarbituric acid reactive substance (TBARS) and decrease in glutathione (GSH), catalase (CAT), and super oxide dismutase (SOD) in testis and spleen tissues. The data also showed significant increase in tumor necrossis factor-α (TNF-α), 8-hydroxy deoxyguanosine (8-OHDG), acid phosphatase (ACP), urea, and creatinine. Furthermore, significant decreases in serum zinc (Zn), copper (Cu), magnesium (Mg), iron (Fe), and testosterone in mercuric chloride group were recorded. The histological examination of testis and spleen tissues showed some degenerative changes while significant improvement in the antioxidant levels, biochemical, trace elements, and histological changes were observed in mercuric chloride group treated with origanum oil. It could be concluded that origanum oil through its antioxidant potential may possess health promoting properties and could protect cells from oxidative damage induced by mercuric chloride.     

Effect of lead with vitamin E, C, or Spirulina on malondialdehyde, conjugated dienes and hydroperoxides in rats

Lead (100 ppm) was given in doubly deionised water for 30 days to one group of rats. The other groups received lead along with exogenous antioxidants like vitamin E (50 IU/kg), vitamin C (800 mg/kg) or Spirulina (1500 mg/kg) in food for a similar period. Levels of lipid peroxidation products such as malondialdehyde, conjugated diene and hydroperoxide were measured in liver, lung and kidney of treated rats. In lead treated animals there was a significant increase in the levels of these lipid peroxidative products. Administration of exogenous antioxidants in the lead treated animals reduced the levels of malondialdehyde, conjugated diene and hydroperoxide. It indicated that vitamin E, vitamin C and Spirulina had significant (P < 0.001) antioxidant activity thereby protecting the animals from lead induced toxicity.     

Effects of neonatal septal lesions on reproductive behavior of male and female rats

The purpose of this study was to examine the effects of neonatally placed septal lesions (SL) in male, female, and androgenized female rats on reproductive behavior. Animals were castrated as adults and tested for both feminine and masculine sexual behavior. After treatment with estradiol benzoate (EB) alone (2 μg daily for 3 days), only the females with SL which had not been given testosterone propionate (TP) neonatally showed a facilitation of lordosis behavior. Following EB (2 μg for 3 days) plus 0.5 mg progesterone (P), both the lesioned and the sham-operated female groups showed an increase in the display of lordosis in either hormonal condition. All animals were given a pretest for masculine sexual behavior and tested on Days 4, 7, 11, and 15 of daily TP treatment (150 μg/day). There was no effect of the neonatally placed SL on masculine sexual behavior in female rats or in female rats androgenized with 30 μg TP. However, lesioned females treated neonatally with 1 mg TP showed a marginal enhancement of masculine sexual behavior. Male rats given SL neonatally showed a marked enhancement of masculine sexual behavior compared to that of controls. These results suggest that, depending on the neonatal hormone environment, SL selectively increase behavioral sensitivity to hormones. Although neonatally lesioned females show behavioral responses similar to females given SL as adults, male rats given SL neonatally are unique in that they show enhanced masculine sexual behavior whereas males lesioned as adults do not.     

Antioxidant effects of Emblica officinalis and Zingiber officinalis on arsenic and lead induced toxicity on Albino rats

It is of interest to document the effect of Emblica officinalis (E. officinalis) and Zingiber officinalae (Z. officinalae) leaf extract on reactive oxygen species, antioxidant potential changes in arsenic and lead-induced toxicity in male rats. We used 8 groups of adult male Wistar rats with 1 control group for this study. The animals were divided into Group I: Control and Group II: Lead and sodium arsenite induced rats (animals were induced for metal toxicity by the combined administration of arsenic (13.8 mg/ kg body weight) and lead (116.4 mg/kg body weight). These doses were administered by gastric intubation during 14 consecutive days using known standard procedures. Arsenic and lead induced rats treated with ethanolic extract of Emblica officinalis (60 mg/kg body weight/day, orally for 45 days) are group III rats. Group IV animals are arsenic and lead induced rats treated orally with ethanolic extracts of E. officinalis (120 mg/kg body weight/day for 45 days). Group V animals are arsenic and lead induced rats treated orally with ethanolic extracts of Z. officinalae (60 mg/kg body weight/day for 45 days). Group VI animals are arsenic and lead induced rats orally treated with ethanolic extracts of Zingiber officinalis (120 mg/kg body weight/day for 45 days). Group VII animals are arsenic and lead induced rats treated orally with ethanolic extracts of E. officinalis and Z. officinalae (60 + 60 mg/kg body weight/day for 45 days). Group VIII animals are arsenic and lead induced rats treated orally with ethanolic extracts of E. officinalis and Z. officinalae (120 + 120 mg/kg body weight/day, orally for 45 days). Normal Control animals were treated orally with ethanolic extracts of E. officinalis (120mg/kg body weight) + Z. officinalae (120mg/kg body weight) for 45 days. The control and experimental animals were then subjected to analysis for oxidative stress markers such as H2O2, *OH, and lipid peroxidation (LPO), antioxidant enzymes in addition to liver and kidney function markers. Results: Arsenic and lead induced rats showed a significant increase in the levels of reactive oxygen species (H2O2, OH* and LPO) with concomitant alterations in the renal and liver tissues. However, enzymic and non-enzymic antioxidant levels were decreased. Nevertheless, an oral effective dose of E. officinalis and Z. officinalae (120 + 120 mg/kg body weight/day increased the antioxidant enzymes and retrieved the altered levels of ROS and LPO that were induced by arsenic and lead. Thus, we show that E. officinalis and Z. officinalae leaf extract exhibits nephroprotective and hepatoprotective role through the restoration of reactive oxygen species and antioxidant enzymes in the kidney and liver tissue of Arsenic and Lead-induced nephrotoxicity and hepatotoxicity in rats. Hence, E. officinalis and Z. officinalae leaf extract are potential therapeutic options for the treatment of metal toxicity-induced kidney and liver diseases.     

Anabolic androgenic steroids differentially affect social behaviors in adolescent and adult male Syrian hamsters

Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone used by over half a million adolescents in the United States for their tissue-building potency and performance-enhancing effects. AAS also affect behavior, including reports of heightened aggression and changes in sexual libido. The expression of sexual and aggressive behaviors is a function of complex interactions among hormones, social context, and the brain, which is extensively remodeled during adolescence. Thus, AAS may have different consequences on behavior during adolescence and adulthood. Using a rodent model, these studies directly compared the effects of AAS on the expression of male sexual and aggressive behaviors in adolescents and adults. Male Syrian hamsters were injected daily for 14 days with either vehicle or an AAS cocktail containing testosterone cypionate (2 mg/kg), nandrolone decanoate (2 mg/kg), and boldenone undecylenate (1 mg/kg), either during adolescence (27-41 days of age) or in adulthood (63-77 days of age). The day after the last injection, males were tested for either sexual behavior with a receptive female or agonistic behavior with a male intruder. Adolescent males treated with AAS showed significant increases in sexual and aggressive behaviors relative to vehicle-treated adolescents. In contrast, AAS-treated adults showed significantly lower levels of sexual behavior compared with vehicle-treated adults and did not show heightened aggression. Thus, adolescents, but not adults, displayed significantly higher behavioral responses to AAS, suggesting that the still-developing adolescent brain is more vulnerable than the adult brain to the adverse consequences of AAS on the nervous system and behavior.     

Steroids and sexual behavior in castrated male rheusus monkeys.

Sexual behavior of long-term castrated rhesus males was not increased by administration of the hydroxylated metabolite of testosterone (T), 17 beta, 19-dihydroxy-5 alpha-androstan-3-one diacetate (19-OH-DHTA) at a dose of 1 mg/kg/day. Simultaneous administration of 19-OH-DHTA and estradiol benzoate (EB) also failed to increase the level of sexual performance, but daily injection (1 mg/kg/day) of testosterone propionate (TP) was very effective in effective in activating sexual behavior.     

Effects of the nonsteroidal aromatase inhibitor, Fadrozole, on sexual behavior in male rats.

The new nonsteroidal aromatase inhibitor, Fadrozole (CGS 16949A, CIBA-Geigy Corp.), was tested for its ability (i) to inhibit the conversion of testosterone (T) to estradiol (E2) in brain and (ii) to suppress male sexual activity. Sprague-Dawley rats were castrated and immediately given sc Silastic T-implants and osmotic minipumps delivering 2.5 mg/kg/day Fadrozole (N = 4), 0.25 mg/kg/day Fadrozole (N = 4), or water (N = 4 controls). T-implants were removed after 6 days and, 3 days later, 3H-T (1 microCi/g) was given as an iv bolus. No 3H-E2 was detected in hypothalamic or amygdaloid nuclear pellets from Fadrozole-treated males but this metabolite predominated in controls. However, nuclear concentrations of 3H-T and [3H]dihydrotestosterone were similar in all groups. In another group of males (N = 18), brain aromatase activity was reduced by more than 96% at the 0.25 mg/kg dose level. Additional castrated, T-implanted males received minipumps delivering 0.25 mg/kg/day Fadrozole (six males) or water (six behaviorally matched controls) and were tested weekly with receptive females. After 2 weeks, ejaculations were reduced by 77% compared with controls (P less than 0.01) and, after 4 weeks, intromissions were also significantly reduced (P less than 0.05) but less so (48%). Radioenzymatic estimates of plasma aromatase inhibitor levels remained elevated throughout Fadrozole treatment. These males were then given Silastic E2 implants: intromissions increased significantly in 1 week (P less than 0.01), but ejaculations remained below control values. Results supported the view that aromatization is important for sexual behavior in male rats and suggested that Fadrozole has utility for studying the mechanisms by which testosterone affects behavior.     

Possible combined effects of 900 MHZ continuous-wave electromagnetic fields and gentamicin on the auditory system of rats

The aim of this study was to evaluate the cochlear functionality of Sprague-Dawley rats exposed to electromagnetic fields at 900 MHz and to gentamicin by distortion product otoacoustic emissions, which are a well-known indicator of the status of the cochlea's outer hair cells. A population of 32 rats was divided into four groups: group 1 was treated with daily intramuscular injections of 150 mg/kg body weight gentamicin for 15 days; group 2 was treated with daily intramuscular injections of 150 mg/kg body weight gentamicin for 15 days and exposed to electromagnetic fields; group 3 was exposed to electromagnetic fields; group 4 was sham-exposed. Rats were exposed 2 h/day, 5 days/week for 4 weeks at a local SAR of 4 W/kg in the ear (continuous wave at 900 MHz). Distortion product otoacoustic emissions tests were carried out before, during and after the combined exposure. The analysis of the data showed no subchronic exposure to electromagnetic fields on the inner auditory system of rats in either normal ears or ears exposed to a well-recognized pathological agent.     

Anabolic-Androgenic Steroid Effects on Sexual Receptivity in Ovariectomized Rats

Anabolic-androgenic steroid (AAS) compounds are synthetic androgens taken by athletes to increase physical strength and endurance. Recent studies in our laboratory have demonstrated that AAS administration disrupts the estrous cycle of Long–Evans rats. The present experiments examined the effects of six commonly abused AAS compounds on sexual receptivity in ovariectomized rats. Adult female Long–Evans rats received estradiol benzoate (EB; 2.0 μg/day sc) for 6 consecutive days followed by 15 days of EB concurrent with daily sc injections of 7.5 mg/kg of one of the following AAS compounds: 17α-methyltestosterone, methandrostenolone, nandrolone decanoate, stanozolol, oxymetholone, testosterone cypionate, or the oil vehicle. On Day 15, all female rats received progesterone (1.0 mg/rat) 4 h before testing. Tests for sexual receptivity were conducted on Days 3, 6, 14, and 15 of AAS treatment. Although the time course of AAS effects on sexual receptivity varied, some overall effects were clear. For example, 17α-methyltestosterone, methandrostenolone, nandrolone decanoate, and stanozolol interfered with the display of sexual receptivity on Day 14, whereas oxymetholone and testosterone cypionate had no effect. Rats in all groups displayed high levels of sexual receptivity after receiving progesterone on Day 15. Our results show that AAS compounds vary in their degree of inhibition of female sexual behavior in ovariectomized rats.     

The effect of dexamethasone on disruption of ovarian steroid levels and receptors in female rats

This study was conducted to investigate if the injection of a single dose of dexamethasone may cause disruption of adult female rat gonadal function in terms of plasma and ovarian level of both androgen and estrogen, ovarian morphology, and changes in localization of androgen, estrogen and glucocorticoid receptors. Adult female Long Evans rats (n=50, 250-300 g) were used. At day 0 rats received subcutaneously 1 ml of saline (n=25; control group) or dexamethasone at 0.1 mg/kg (n=25, treated group). Rats were sacrificed in groups of five on days 10, 15, 20, 25 and 30 after injection. Blood samples and one ovary were collected to analyze dexamethasone, 17beta-estradiol (E2), testosterone (T) and androstenedione (A4) concentrations by amplified EIA. The remaining ovary was removed and processed for histopathology and immunocytochemistry. Differences between individual means were analyzed by Pairwise t-test and Bonferroni post test to asses whether values presented statistical significance. Increased E2, T and A4 levels were observed both in plasma and ovary samples in treated group when comparing with control (p< 0.01) at all days post-injection even when dexamethasone was undetectable. Ovarian morphology of treated group showed features compatible with female infertility. Inmmunolocalization of androgen and estrogen receptors showed that both were negative in treated group while controls showed highest positivity (AR +++, ER ++). Glucocorticoid receptor showed higher positivity in dexamethasone treated rats (GR ++) than in controls (GR +). Obtained results showed clear evidence that a single dose of dexamethasone may disrupt gonadal function in rats, and that possibly leads to infertility.     

Chronic corticosterone treatment impairs Leydig cell 11beta-hydroxysteroid dehydrogenase activity and LH-stimulated testosterone production.

The effects of excess corticosterone on luteinizing hormone (LH)-stimulated Leydig cell testosterone production and activity of 11beta-HSD was studied. Adult male rats (200-250 g body weight) were treated with corticosterone-21-acetate (2 mg/100 g body weight, i.m., twice daily) for 15 days. Another set of rats was treated with corticosterone (dose as above) plus LH (ovine LH 100 microg/kg body weight, s.c., daily) for 15 days. Corticosterone administration significantly increased serum and testicular interstitial fluid (TIF) corticosterone but decreased testosterone levels. Administration of LH with corticosterone partially prevented the decrease in serum and TIF testosterone. The oxidative activity of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) was significantly decreased in Leydig cells of rats treated with corticosterone alone and in combination with LH. The direct effect of corticosterone on Leydig cell steroidogenic potency was also studied in vitro. Addition of corticosterone to Leydig cell culture showed a dose dependent effect on LH-stimulated testosterone production. Corticosterone at 50 and 100 ng/ml did not alter LH-stimulated testosterone production, but at high doses (200-400 ng/ml), decreased basal and LH-stimulated testosterone production. Basal and LH-stimulated cAMP production was not altered by corticosterone in vitro. It is concluded from the present study that elevated levels of corticosterone decreased the oxidative activity of 11beta-HSD and thus resulting in impaired Leydig cell steroidogenesis and the inhibitory effects of corticosterone on testosterone production appear to be mediated through inhibition of LH signal transduction at post-cAMP level.     

Effects of oral administration of nicotine on organ weight, serum testosterone level and testicular histology in adult male rats

This study investigated the effects of oral administration of nicotine on body and reproductive organ weight, serum testosterone level and testicular histology in adult male rats. Forty male rats divided into five groups and treated for a period of 30 days with 0.5mg/kg (low dose) and 1.0 mg/kg (high dose) body weight of nicotine while the control rats received 0.2 ml/kg normal saline. The fourth and fifth groups were gavaged with 0.5mg/kg and 1.0mg/kg body weight of nicotine but were left untreated for another 30 days. These groups served as the recovery groups.  At the end of each experimental period, the animals were scarified and their reproductive organs were removed and weighed immediately. There was no significant change in the body weight. There was a significant decrease (p <0.05) in the testicular and epididymal weight of rats for both treatments while the decrease in the seminal vesicle weight for both treatment groups was not significant. The prostate weight was not significantly increased in both groups. The recovery groups showed appreciable recovery in their organ weight. Serum level of testosterone of both groups was significantly decreased in a dose dependent manner when compared with those of the control rats. The histological section showed testicular degeneration and disorganization in the cytoarchitecture, as the observed changes were pronounced in the high dose group than the low dose group. However, there were both regeneration of the germinal epithelium and restructuring of the interstitum towards normal in the recovery groups. No lesion was observed in the epididymis of the rats. The results suggest that nicotine has deleterious effect on the male reproductive organ of albino rats ameliorated by nicotine cessation.     

Effect of growth hormone in an experimental model of protein hypercatabolism induced by glucocorticoids.

OBJECTIVE: The aims of the study were to evaluate whether growth hormone could be beneficial in a model of hypercatabolism induced by glucocorticoids and to examine its effects on ACTH, corticosterone and IGF-1 levels. The effects of growth hormone on the expression of both glucocorticoid receptor and tyrosine aminotransferase were also evaluated. METHODS: Fifty Wistar rats were divided into five groups and treated as follows: (A) daily subcutaneous injection of growth hormone (4.8 IU/kg/day) and oral placebo, (B) daily injection of placebo and oral dexamethasone (3 mg/kg/day), (C) daily injection of growth hormone and oral dexamethasone, (D) daily injection of placebo and oral placebo, and (E) no treatment. The animals were decapitated seven days after initiating treatment. RESULTS: Growth hormone did not modify the weight loss induced by dexamethasone. Glucocorticoid receptor expression was significantly lower in group A than in group E. An increase in tyrosine aminotransferase was observed in group C. CONCLUSION: Growth hormone did not exert any beneficial effect in this model of hypercatabolism. Growth hormone decreased glucocorticoid receptor expression. This fact could explain its beneficial effect when protein hypercatabolism is not the predominant phenomenon. Growth hormone induced the hyperexpression of tyrosine aminotransferase, thus suggesting an amplifying effect on the glucocorticoid action.