scholarly journals Erectile Dysfunction Drugs Changed the Protein Expressions and Activities of Drug-Metabolising Enzymes in the Liver of Male Rats

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Salah A. Sheweita ◽  
Mona Wally ◽  
Mostafa Hassan

Erectile dysfunction (ED) is a major health problem and is mainly associated with the persistent inability of men to maintain sufficient erection for satisfactory sexual performance. Millions of men are using sildenafil, vardenafil, and/or tadalafil for ED treatment. Cytochrome P450s (CYPs) play a central role in the metabolism of a wide range of xenobiotics as well as endogenous compounds. Susceptibility of individuals to the adverse effects of different drugs is mainly dependent on the expression of CYPs proteins. Therefore, changes in activities of phase I drug-metabolising enzymes [arylhydrocarbon hydroxylase (AHH), dimethylnitrosamine N-demethylase (DMN-dI), 7-ethoxycoumarin-O-deethylase (ECOD), and ethoxyresorufin-O-deethylase ((EROD)] and the protein expression of different CYPs isozymes (CYP1A2, CYP2E1, CYP2B1/2, CYP3A4, CYP2C23, and CYP2C6) were determined after treatment of male rats with either low or high doses of sildenafil (Viagra), tadalafil (Cialis), and/or vardenafil (Levitra) for 3 weeks. The present study showed that low doses of tadalafil and vardenafil increased DMN-dI activity by 32 and 23%, respectively. On the other hand, high doses of tadalafil, vardenafil, and sildenafil decreased such activity by 50, 56, and 52%, respectively. In addition, low doses of tadalafil and vardenafil induced the protein expression of CYP2E1. On the other hand, high doses of either tadalafil or sildenafil were more potent inhibitors to CYP2E1 expression than vardenafil. Moreover, low doses of both vardenafil and sildenafil markedly increased AHH activity by 162 and 247%, respectively, whereas high doses of tadalafil, vardenafil, and sildenafil inhibited such activity by 36, 49, and 57% and inhibited the EROD activity by 39, 49, and 33%, respectively. Low and high doses of tadalafil, vardenafil, and sildenafil inhibited the activity of NADPH-cytochrome c reductase as well as its protein expression. In addition, such drugs inhibited the expression of CYP B1/2 along with its corresponding enzyme marker ECOD activity. It is concluded that changes in the expression and activity of phase I drug-metabolising enzymes could change the normal metabolic pathways and might enhance the deleterious effects of exogenous as well as endogenous compounds.

1987 ◽  
Vol 2 (4) ◽  
pp. 296-305 ◽  
Author(s):  
P. Boyer ◽  
A.J. Puech

SummaryAs emphasized by Lecrubier in 1980, the major finding of the last thirty years of classical neuroleptic use in schizophrenia is not that they are antischizophrenic or antipsychotic agents, but that they act on positive symptoms whatever the cause. There is now a widely accepted attribution of this kind of therapeutic property to the post-synaptic dopaminergic blockade induced by most of the neuroleptics when administered at high doses. On the other hand, during the last decade, various authors have reported clear evidence for a disinhibitory action of some neuroleptics when used at low doses. From a clinical point of view, the literature on the therapeutic action of low doses of neuroleptics seems quite controversial. In order to assess the exact determinants for clinical activity of neuroleptics (such as patient type, selected substances, administered doses) two series of independent controlled studies were conducted.First series of studies: active drugs at low and high doses in schizophrenic patients(Tables 1 to 6)The first study was designed to assess the change of negative symptoms under low doses of neuroleptics. Sixty-two patients meeting the DSM III criteria of schizophrenia (subtypes: disorganized, catatonic or residual) were randomly assigned after a three-week washout period to six weeks’ treatment with either amisulpride (50 to 300 mg/day) or fluphenazine (2 to 12 mg/day), administered in keeping with a flexible dosage schedule. All patients had to meet the Andreasen criteria for negative symptoms (at least two of the following components had to be checked as present: anhedonia, alogia, affective flattening, avolition-apathy, attentional impairment). None of the patients presented one of the positive components to a marked degree: hallucinations, delusions, bizarre behavior, positive formal thought disorders. The evolution of symptomatology was assessed by means of the Brief Psychiatric Rating Scale (B.P.R.S.) and an ad hoc defective symptoms scale (D.S.A.S.), the sensitivity and reliability of which was previously tested in our department. The results show that the two groups (amisulpride versus fluphenazine) were initially highly comparable. Negative symptoms were severe, as evidenced by the D.S.A.S. scores, and by the presence of three items of the A6 criterion of the DSM III. The final global clinical assessment and the final D.S.A.S. scores both showed a significant improvement, with no statistically significant difference between the two treatments. Nevertheless, the scores of the “anergia” and “anxiety-depression” factors of the B.P.R.S. showed a significantly greater improvement in the amisulpride group.The second study, complementary to the first, aimed to check the efficacy of high doses of amisulpride on the productive symptoms of schizophrenia. In this case, only the B.P.R.S. was used due to the good correlation of this scale with the global severity of the positive symptomatology. After three weeks of treatment, consisting either of amisulpride at a high, flexible dosage (800 to 1200 mg/day) or of haloperidol (20 to 30 mg/day), each of the two groups of twenty patients showed a significant improvement. In particular, the “thought disorders” factor of the B.P.R.S. (which unfortunately does not correspond exactly to the “formal thought disorder” component of the Andreasen positive symptoms scale - S.A.P.S.) was greatly improved in both groups. Evolution of the other symptoms was however identical in the two groups.Second series of studies: active drugs versus placebo in schizophrenia(Figures 1 to 6)As we know, dopaminergic blocking agents are able to induce negative symptomatology. Consequently, to separate the secondary syndrome from the true deficit, a longer washout period than that previously described has to be imposed. On the other hand, the longitudinal course of schizophrenia must be taken into account for correct interpretation of changes in symptomatology; for example, patients with negative symptoms may abruptly present productive episodes, in particular during the neuroleptic withdrawal period. For optimal control of these two variables (natural history of the disease, the blunting effect of neuroleptics), 90 patients presenting either or both subtypes of schizophrenia were selected and included in a two-step, double-blind, controlled study. Patients with negative symptoms underwent a six-week washout period, after which they were treated either with low doses of amisulpride (100 or 300 mg/day) or a placebo. Patients with initial positive symptoms received mandatory high doses of amisulpride. According to the protocol, negative patients presenting productive symptoms during the washout period were to be systematically assigned to the highdose group. First results concerning 38 patients with a predominant negative symptomatology are presented here. A very clear improvement can be shown both for the SANS global mean score and for the sum of global ratings in the groups treated with low doses of amisulpride compared to the placebo group. The scores of the alogia, blunted affect and attentional impairment subscales decrease dramatically as well with the active drug.


1989 ◽  
Vol 8 (6) ◽  
pp. 1103-1114 ◽  
Author(s):  
Samuel M. Cohen ◽  
Leon B. Ellwein

A biological model of carcinogenesis has been developed that can be expressed mathematically, and therefore can be studied using computer-based analyses. It is based on several assumptions: Carcinogenesis occurs in two stages: initiation and transformation (to malignant tumors); the carcinogenic events can occur only in stem cells or their functional equivalents; these events can occur only during the active part of the cell cycle; each of the events occurs in a probabilistic fashion. Cell dynamics are thus an extremely important part of carcinogenesis. Any agent can have an impact on the carcinogenic process by either directly altering the genome (genotoxic) or increasing the proliferative rate of the tissues: increasing the number of cell divisions through which a spontaneous alteration in the genome can occur; or an agent can affect both of these. Effects on the genome and on cell proliferation can have different dose-responses. Extrapolation to low doses requires consideration of the dose-response for each effect. Differences in mechanisms affecting cell proliferation and genetic changes need to be considered in determining thresholds. The model was originally validated utilizing tumor incidence data from multiple experiments with the carcinogen, N-[4-(5-nitro-2-furyl)2-thiazolyl]-formamide (FANFT), in rats. FANFT is a strong mutagen, is metabolically activated to a reactive electrophile, binds to DNA, and also increases cell proliferation. Modeling analyses demonstrate that the tumor dose-response curve for FANFT can be explained based on a combination of the individual dose-response of its genotoxic and cell proliferation effects. Modeling of a nongenotoxic compound, sodium saccharin (Na S), has also been evaluated. It is not metabolized to a reactive electrophile (it is actually nucleophilic), does not bind to DNA, and is not mutagenic. Nevertheless, in two-generation experiments at high doses it induces a significant incidence of bladder tumors in male rats. It is also a strong tumor-promoting substance following chemical initiation or bladder ulceration. These complex protocols can be readily explained by the proliferative response induced in the urothelium following Na S administration. As expected for a nongenotoxic chemical, there is no effect on the probability of initiation or transformation. Unlike the sodium salt, high doses of the calcium and acid forms of saccharin do not increase cell proliferation significantly, and would not be anticipated to induce tumors. Also, there appears to be a threshold effect related to dose of Na S and the induction of urothelial proliferation. Since cell proliferation is the mechanism by which Na S induces bladder tumors in rats, it is expected that there is also a threshold with respect to carcinogenesis. By allowing for agents to be defined in terms of their ability to affect the genome directly or to act as cell proliferators, model-based analyses provide a rational basis for extrapolating from high doses in animal experiments to low doses in assessing risk for humans.


1954 ◽  
Vol 32 (6) ◽  
pp. 625-627
Author(s):  
G. Stuart Wiberg ◽  
Jules Tuba

Adult male rats did not display an elevated serum amylase following injection of codeine. Mice, on the other hand, showed significantly increased values of the enzyme after treatment with codeine. The significance of these findings are discussed from the standpoint of the tonus of the sphincter of Oddi, and the presence or absence of a gall bladder.


1976 ◽  
Vol 54 (4) ◽  
pp. 516-519 ◽  
Author(s):  
C. Ezrin-Waters ◽  
P. Muller ◽  
P. Seeman

To investigate the extent of cholinergic involvement in opiate-induced catalepsy, the effects of three anticholinergic drugs were studied on morphine-induced catalepsy. Haloperidol-induced catalepsy was also examined. Maximum catalepsy in rats was obtained with 30 mg/kg morphine or 3 mg/kg haloperidol. The anticholinergic drugs atropine, benztropine, and scopolamine were unable to antagonize morphine-induced catalepsy, yet readily antagonized haloperidol-induced catalepsy. Low doses of apomorphine (7.5 mg/kg), on the other hand, readily antagonized morphine catalepsy, but 13-fold higher doses of apomorphine were needed to block haloperidol-induced catalepsy. The results are compatible with the idea that catalepsy can be mediated via the striatum or the amygdala; morphine–dopamine antagonism may occur in the amygdala, whereas morphine–dopamine–cholinergic interactions occur in the striatum.


1972 ◽  
Vol 52 (1) ◽  
pp. 11-22 ◽  
Author(s):  
F. MENA ◽  
C. E. GROSVENOR

SUMMARY The results of experiments in which the prolactin in the primiparous rat pituitary was bioassayed suggested that the failure of suckling to release prolactin after 8 h of non-suckling on day 21 post-partum was due to the fact that prolactin had been discharged from the pituitary during the 8-h non-suckling period, presumably by exteroceptive signals emanating from the general environment of the animal room. This was substantiated in other experiments in which prolactin release was assessed indirectly through its stimulatory effects upon milk secretion. In these experiments, the mammary glands of rats maintained continuously in the animal room filled faster on day 21 after complete emptying of the glands by exogenous oxytocin, than did either rats on day 14 post-partum maintained continuously in the animal room or rats isolated in a room without other rats on day 21 post-partum. The glands of the latter two groups of rats could be stimulated to fill faster provided prolactin was injected 4 h before the initial emptying of the glands. The exteroceptive stimuli in the animal room environment that stimulated the release of prolactin in the 21-day post-partum rat apparently emanated at least in part from other lactating rats and/or their litters, since faster mammary gland refilling occurred in isolated 21 day post-partum rats when they were exposed to the presence of lactating rats with their litters for 30 min halfway through the 8-h non-suckling period which preceded the initial emptying of the gland. Exposure to male rats, on the other hand, was totally ineffective. A release of prolactin occurred in response to animal room environmental stimuli in the day 14 primiparous rat provided 13–14 day old foster pups were inserted in place of the mother's own pups on day 7. Thus, the rapidly changing characteristics of the pups from 14 to 21 days of age in some manner is involved in the increasing responsiveness of the exteroceptive mechanism for prolactin release which occurs from day 14 to day 21 post-partum.


2021 ◽  
Vol 11 ◽  
Author(s):  
Chenyu Mao ◽  
Yongfeng Ding ◽  
Nong Xu

Prostate cancer (PC) is one of the most common malignancies among men and is the second leading cause of cancer death. PC immunotherapy has taken relatively successful steps in recent years, and these treatments are still being developed and tested. Evidence suggests that immunotherapy using cytokines as essential mediators in the immune system may help treat cancer. It has been shown that cytokines play an important role in anti-tumor defense. On the other hand, other cytokines can also favor the tumor and suppress anti-tumor responses. Moreover, the dose of cytokine in cancer cytokine-based immunotherapy, as well as the side effects of high doses, can also affect the outcomes of treatment. Cytokines can also be determinative in the outcome of other immunotherapy methods used in PC. In this review, the role of cytokines in the pathogenesis of cancer and their impacts on the main types of immunotherapies in the treatment of PC are discussed.


1970 ◽  
Vol 7 (1) ◽  
pp. 5-9
Author(s):  
Md Jahangir Alam ◽  
Monira Khatun ◽  
Manowara Begum ◽  
Muazzem Hossain ◽  
Jesmin Akhter ◽  
...  

Context: Indomethacin is the most commonly and widely used nonsteroidal antiinflammatory analgesic and antipyretic drug. Despite its effectiveness as an antiinflammatory use, indomethacin causes inhibition of spermatogenesis leading to infertility. On the other hand, vitamin E enhances spermatogenesis. Therefore, the present study was designed to observe the protective role of vitamin E on indomethacin induced testicular damage. Objective: To observe the effects of vitamin E on indomethacin induced testicular damage in Long Evans rats. Study design: An experimental study. Place and period of study: The study was carried out in the Department of Anatomy, Sir Salimullah Medical College, Dhaka. Materials and methods: Eightyfour mature Long Evans male rats were divided into four groups (I, II, III and IV). The rats of group I, II and III were treated with indomethacin at different doses and duration. Group IV rats were treated with indomethacin and vitamin E at different doses for 49 days. Histologically the number of sperm containing and nonsperm containing seminiferous tubules were counted. Results: There was significant reduction (P<0.001) in number of sperm containing seminiferous tubules when the rats were treated with indomethacin at low (2 mg/kg body wt/day) and high dose (10 mg/kg body wt/day) for 7, 14 and 42 days, respectively. On the other hand, rats treated with indomethacin and vitamin E for 49 days showed increase in number of sperm containing seminiferous tubules compared to the other groups (P<0.001). Conclusion: It can be concluded from this study that vitamin E has potential role in the prevention of the antispermatogenic effects of indomethacin. Key words: Seminiferous tubules, Indomethacin, Vitamin E    doi: 10.3329/bja.v7i1.3009 Bangladesh Journal of Anatomy January 2009, Vol. 7 No. 1 pp. 5-9


1954 ◽  
Vol 32 (1) ◽  
pp. 625-627 ◽  
Author(s):  
G. Stuart Wiberg ◽  
Jules Tuba

Adult male rats did not display an elevated serum amylase following injection of codeine. Mice, on the other hand, showed significantly increased values of the enzyme after treatment with codeine. The significance of these findings are discussed from the standpoint of the tonus of the sphincter of Oddi, and the presence or absence of a gall bladder.


2002 ◽  
Vol 227 (9) ◽  
pp. 786-793 ◽  
Author(s):  
W.H. Yu ◽  
S. Karanth ◽  
C.A. Mastronardi ◽  
S. Sealfon ◽  
C. Dean ◽  
...  

Lamprey gonadotropin-releasing hormone-III (I-GnRH-III), the putative follicle-stimulating hormone (FSH)-releasing factor (FSHRF), exerts a preferential FSH-releasing activity in rats both in vitro and in vivo. To test the hypothesis that I-GnRH-III acts on its own receptors to stimulate gonadotropin release, the functional activity of this peptide at mammalian (m) leutinizing hormone (LH)RH receptors transfected to COS cells was tested. I-GnRH-III activated m-LHRH receptors only at a minimal effective concentration (MEC) of 10–6 M, whereas m-LHRH was active at a MEC of 10–9 M, at least 1,000 times less than that required for I-GnRH-III. In 4-day monolayer cultured cells, I-GnRH-III was similarly extremely weak in releasing either LH or FSH, and, in fact, it released LH at a lower concentration (10–7 M) than that required for FSH release (10–6 M). In this assay, m-LHRH released both FSH and LH significantly at the lowest concentration tested (10–10 M). On the other hand, I-GnRH-III had a high potency to selectively release FSH and not LH from hemipituitaries of male rats. The results suggest that the cultured cells were devoid of FSHRF receptors, thereby resulting in a pattern of FSH and LH release caused by the LHRH receptor. On the other hand, the putative FSH-releasing factor receptor accounts for the selective FSH release by I-GnRH-III when tested on hemipituitaries. Removal of calcium from the medium plus the addition of EGTA, a calcium chelator, suppressed the release of gonadotropins induced by either I-GnRH-III or LHRH, indicating that calcium is required for the action of either peptide. Previous results showed that sodium nitroprusside, a releaser of nitric oxide (NO), causes the release of both FSH and LH from hemipituitaries incubated in vitro. In the present experiments, a competitive inhibitor of NO synthase, L-NG-monomethyl-l-arginine (300 μM) blocked the action of I-GnRH-III or partially purified FSHRF. The results indicate that I-GnRH-III and FSHRF act on putative FSHRF receptors by a calcium-dependent NO pathway.


1994 ◽  
Vol 49 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Kerstin Uvnäs-Moberg ◽  
S. Ahlenius ◽  
V. Hillegaart ◽  
P. Alster
Keyword(s):  

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