Changes in circulating androgens during short term carbamazepine therapy

The Effects of Weak and Strong CYP3A Induction by Rifampicin on the Pharmacokinetics of Five Progestins and Ethinylestradiol Compared to Midazolam

It is known that co‐administration of CYP3A inducers may decrease the effectiveness of oral contraceptives containing progestins as mono‐preparations or combined with ethinylestradiol. In a randomized clinical drug‐drug interaction study, we investigated the effects of CYP3A induction on the pharmacokinetics of commonly used progestins and ethinylestradiol. Rifampicin was used to induce CYP3A. The progestins chosen as victim drugs were levonorgestrel, norethindrone, desogestrel, and dienogest as mono‐products, and drospirenone combined with ethinylestradiol. Postmenopausal women (n = 12–14 per treatment group) received, in fixed sequence, a single dose of the victim drug plus midazolam without rifampicin, with rifampicin 10 mg/day (weak induction), and with rifampicin 600 mg/day (strong induction). The effects on progestin exposure were compared with the effects on midazolam exposure (as a benchmark). Unbound concentrations were evaluated for drugs binding to sex hormone binding globulin. Weak CYP3A induction, as confirmed by a mean decrease in midazolam exposure by 46%, resulted in minor changes in progestin exposure (mean decreases: 15–37%). Strong CYP3A induction, in contrast, resulted in mean decreases by 57–90% (mean decrease in midazolam exposure: 86%). Namely, the magnitude of the observed induction effects varied from weak to strong. Our data might provide an impetus to revisit the currently applied clinical recommendations for oral contraceptives, especially for levonorgestrel and norethindrone‐containing products, and they might give an indication as to which progestin could be used, if requested, by women taking weak CYP3A inducers—although it is acknowledged that the exact exposure‐response relationship for contraceptive efficacy is currently unclear for most progestins.

Sexual dysfunction in people with epilepsy

Sexual dysfunction is a common comorbidity in people with epilepsy (PWE) that adversely affects their quality of life. Nearly one-half of men and women with epilepsy have sexual dysfunction, but in the majority, this often goes unnoticed. The wide variation in the reported prevalence of sexual dysfunction in PWE is due to the significant heterogeneity among the studies with regard to patient population, type and severity of epilepsy, number and type of antiseizure drugs (ASDs) used, and the tools used for assessing sexual dysfunction. Generally, patients with uncontrolled epilepsy, longer duration of epilepsy, focal epilepsy, higher seizure frequency, and those receiving enzyme-inducing and multiple ASDs are more likely to have sexual dysfunction. Women generally have dysfunction in the domains of desire, while males usually have arousal disorders such as erectile dysfunction and premature ejaculation. There is limited evidence to indicate that sexual function improves in patients rendered seizure-free following epilepsy surgery. Multiple mechanisms including direct effects of epilepsy, effects of ASDs, and psychosocial factors contribute to sexual dysfunction in epilepsy. Circumstantial evidence indicates that seizures and interictal epileptiform discharges can directly affect the hypothalamic-pituitary axis as well as production of gonadal steroids. Enzyme-inducing ASDs cause sexual dysfunction by affecting the metabolism of gonadal steroids. Limited data suggest that newer ASDs including oxcarbazepine, lamotrigine, and levetiracetam cause no or minimal sexual dysfunction. Depression and anxiety significantly contribute to sexual dysfunction in PWE. A multipronged and multidisciplinary approach is essential for optimizing the sexual functions. Every effort should be made to identify and treat reversible causes including changing to nonenzyme-inducing ASDs and to provide symptomatic relief. Large, prospective studies are required to improve our understanding on prevalence and mechanisms of sexual dysfunction in PWE.

Transcriptome analysis of the brain of the sea bream (Sparus aurata) after exposure to human pharmaceuticals at realistic environmental concentrations

Human pharmaceuticals such as Acetaminophen, Atenolol and Carbamazepine are pseudo persistent aquatic pollutants with yet unknown sub-lethal effects at environmentally relevant concentrations. Gilthead seabream (Sparus aurata) were exposed to Acetaminophen: 31.90 ± 11.07 μg L^-1; Atenolol: 0.95 ± 0.38 μg L^-1 and Carbamazepine: 6.95 ± 0.13 μg L^-1 in a 28 day flow through experiment to (1) determine whether exposure to low concentrations in the μg·L^-1 range of the pharmaceuticals alters the brain transcriptome and, (2) identify different expression profiles and treatment specific modes of action and pathways. Despite low exposure concentrations, 411, 7 and 612 differently expressed transcripts were identified in the individual treatments with Acetaminophen, Atenolol and Carbamazepine, respectively. Functional analyses of differentially expressed genes revealed a significant over representation of several biological processes, cellular compartment features and molecular functions for both Acetaminophen and Carbamazepine treatments. Overall, the results obtained in seabream brain suggest similar physiological responses to those observed in humans also at environmental concentrations, as well as the existence of treatment specific processes that may be useful for the development of biomarkers of contamination.

Relation between Sexual Dysfunctions and Epilepsy, Type of Epilepsy, Type of Antiepileptic Drugs: A Prospective Study

Introduction

The aim of this study was to evaluate the incidence of sexual dysfunctions in males with epilepsy, the type of epilepsy, the frequency of seizures, the type of antiepileptic drugs (AEDs), the serum hormonal profile and the presence of psychiatric comorbidity.

Methods

Sixty-one patients focused on type of epilepsy, frequency of seizures, AEDs, hormonal profile and presence of mood disorders. We excluded all patients with severe neurologic and psychiatric impairment and patient who were not able to fill questionnaires. Mean age was 31.2 years (range 18-50 years); 31 patients (50.8%) had an idiopathic generalised epilepsy and 30 (49.2%) a focal epilepsy; among them, latter 18 (60%) had probably symptomatic type and 12 (40%) symptomatic type. Sexual functions were evaluated by “International Inventory of Erectile Function” questionnaire.

Results

Out of 61 enrolled patients, 22 (36.7%) showed sexual dysfunctions: erectile dysfunctions in 14 (23%), orgasmic dysfunctions in (11.5%) and sexual drive dysfunctions in 12 (19.7%). Out of 61 patients, 36 were subjected to blood measurement of sexual hormones and 21 (58.3%) showed hormonal modifications.

Conclusions

Sexual dysfunction are present in 36.7% of enrolled males with epilepsy; there is any association between sexual dysfunctions and various AEDs in the treatment, except for carbamazepine (CBZ); there is not any association between sexual dysfunctions and frequency of seizures; hormonal changes are associated with sexual dysfunction in males with epilepsy treated with AEDs but not with the orgasmic dysfunction; there is not any association between hormonal changes and type of AEDs, except for CBZ; depression is associated with sexual dysfunctions.

Psychotropics and Male Reproduction

Psychotropic drugs, including antidepressants, antipsychotics, and anticonvulsants, all have negative effects on sexual function and semen quality. These adverse events vary among men and are less pronounced for some medications, allowing their effects to be managed to some extent. Use of specific serotonin reuptake inhibitors (SSRIs) is prevalent in men of reproductive age; and application to treat premature ejaculation increases the number of young men on SSRI therapy. Oxidative damage to sperm can result from prolonged residence in the male reproductive tract. The increase in ejaculatory latency seen with SSRIs likely underlies some of their negative effects on semen quality, including higher sperm DNA fragmentation, seen in all SSRIs evaluated thus far. These medications increase prolactin (PRL) levels in some men, and this is often credited with inhibitory effects on male reproduction; however, testosterone levels are generally normal, reducing the likelihood of direct HPG axis inhibition by PRL. The tricyclic antidepressants have also been shown to increase PRL levels in some studies but not in others. The exception is the tricyclic antidepressant clomipramine, which profoundly increases PRL levels and may depress semen quality. Other antidepressants modulating synaptic levels of serotonin, norepinephrine, and/or dopamine may have toxicity similar to SSRIs, but most have not been evaluated. In limited studies, norepinephrine-dopamine reuptake inhibitors (NDRIs) and serotonin agonist/reuptake inhibitors (SARIs) have had minimal effects on PRL levels and on sexual side effects. Antipsychotic medications increase PRL, decrease testosterone, and increase sexual side effects, including ejaculatory dysfunction. The greatest evidence is for chlorpromazine, haloperidol, reserpine, risperidone, and thioridazine, with less effects seen with aripiprazole and clozapine. Remarkably few studies have looked at antipsychotic effects on semen quality, and this is an important knowledge gap in reproductive pharmacology. Lithium increases PRL and LH levels and decreases testosterone although this is informed by few studies. The anticonvulsants, many used for other indications, generally decrease free or bioavailable testosterone with variable effects on the other reproductive hormones. Valproate, carbamazepine, oxcarbazepine, and levetiracetam decrease semen quality; other anticonvulsants have not been investigated for this adverse reaction. Studies are required evaluating endpoints of pregnancy and offspring health for psychotropic medications.

The relationship between epilepsy and sexual dysfunction: a review of the literature

Background and objectives

Regardless of the disease states that people suffer from, maintaining sexual function is an important indicator of quality of life. The objective of this review was to figure out the relationship between epilepsy, antiepileptic drugs (AEDs) and sexual dysfunction.

Results

In various epidemiological and clinical studies, epilepsy has been correlated with a reduction in sexual function. This sexual dysfunction is not always detected in epileptic patients until systematic efforts are put in place, as part of the assessment and treatment process. Therefore, precise evaluations of the incidence of treatment related sexual dysfunction in epileptic patients is still lacking.

Conclusions

This literature review concluded that sexual function is influenced by the pathophysiology of epilepsy, as well as through the use of AEDs. To maximize quality of care in patients with epilepsy and those patients with other disease states who receive AEDs, it is important to address the status of the patient’s sexual function as part of the initial routine assessment and with any treatment related follow-up. Minimizing the effects of AED related sexual dysfunction can be achieved by raising awareness among patients, providing education and training for physicians regarding sexual dysfunction and obtaining a baseline sexual history from the patient so are important recommendations. In addition, systematic studies are needed to explore the risk and mechanism of such treatment related side effects on sexual function.

Treatment of hypopituitarism in patients receiving antiepileptic drugs

Evidence suggests that there may be drug interactions between antiepileptic drugs and hormonal therapies, which can present a challenge to endocrinologists dealing with patients who have both hypopituitarism and neurological diseases. Data are scarce for this subgroup of patients; however, data for the interaction of antiepileptic drugs with the pituitary axis have shown that chronic use of many antiepileptic drugs, such as carbamazepine, oxcarbazepine, and topiramate, enhances hepatic cytochrome P450 3A4 (CYP3A4) activity, and can decrease serum concentrations of sex hormones. Other antiepileptic drugs increase sex hormone-binding globulin, which reduces the bioactivity of testosterone and estradiol. Additionally, the combined oestrogen-progestagen contraceptive pill might decrease lamotrigine concentrations, which could worsen seizure control. Moreover, sex hormones and their metabolites can directly act on neuronal excitability, acting as neurosteroids. Because carbamazepine and oxcarbazepine can enhance the sensitivity of renal tubules, a reduction in desmopressin dose might be necessary in patients with central diabetes insipidus. Although the effects of antiepileptic drugs in central hypothyroidism have not yet been studied, substantial evidence indicates that several antiepileptic drugs can increase thyroid hormone metabolism. However, although it is reasonable to expect a need for a thyroxine dose increase with some antiepileptic drugs, the effect of excessive thyroxine in lowering seizure threshold should also be considered. There are no reports of significant interactions between antiepileptic drugs and the efficacy of human growth hormone therapy, and few data are available for the effects of second-generation antiepileptic drugs on hypopituitarism treatment.

Role of androgens in epilepsy

Accumulating evidence suggests that both male- and/or female-typical sex steroids contribute to seizure susceptibility in epilepsy. Although there is rich literature regarding how female-typical sex steroids, such as progestins and estrogens, influence epilepsy, the role of androgens in seizure processes are just beginning to be understood. Given that some of the effects and mechanisms of androgen action on ictal activity may converge with that of progestins and/or estrogens, this review discusses what is known concerning the role of each of these sex steroids on seizures. Additionally, evidence that seizures and/or antiepileptic drugs can themselves influence steroid-dependent behaviors, such as affective, cognitive and reproductive function, is also reviewed. Considerations for therapeutic management and future directions for research and drug discovery are summarized.

Human sexuality, sex hormones, and epilepsy

The function of the hypothalamic-pituitary axis (HPA), including the production of luteinizing hormone, follicle-stimulating hormone, gonadotropin-releasing hormone, and prolactin, and the concentrations and metabolism of its end products, such as estrogen, testosterone, and dehydroepiandrosterone, appear to be modified in many people with epilepsy. Effects of the disorder itself and effects of antiepileptic drugs (AEDs) both appear to contribute to these hormonal alterations, which may be associated with sexual dysfunction. Focal epileptic discharges from the temporal lobe may affect HPA function, as is suggested by the normalization of androgen levels seen in men with temporal lobe epilepsy who become seizure-free after surgery. Hepatic enzyme-inducing AEDs such as carbamazepine and phenytoin may be most clearly linked to altered metabolism of sex steroid hormones, but valproic acid, an enzyme inhibitor, has also been implicated in the causation of reproductive endocrine abnormalities. Polycystic ovaries and polycystic ovarian syndrome (PCOS) are widely believed to be common in women with epilepsy, but the actual prevalence and the pathogenesis of PCOS in this population are disputed. Hormonal changes and sexual dysfunction need to be addressed in any comprehensive approach to epilepsy management, as well as any comprehensive epilepsy research program. Avoidance of enzyme-inducing AEDs and achievement of freedom from seizures as the goal of treatment are strongly recommended.

Reproductive and sexual dysfunction in men with epilepsy

Disturbances of reproductive and sexual health are common in people with epilepsy. Their etiology is not well understood but appears to be multifactorial, and both epilepsy itself and drugs used to treat it are implicated. Physiologically, sex steroid hormone levels, the hypothalamic-pituitary axis, and testicular function can be affected in men with epilepsy. Psychosocial complications associated with epilepsy can also affect reproductive health and sexuality. Clinicians need to investigate such problems carefully, both because of their multifactorial nature and because patients and physicians alike may often fail to recognize or be reluctant to acknowledge them; in particular, patients whose epilepsy had its onset before puberty may lack subjective awareness of impairments of sexual response and function. Treatments for reproductive and sexual dysfunction in men with epilepsy have been inadequately studied. Modalities such as medications for erectile dysfunction and surgery may be useful. Therapy with exogenous testosterone and an aromatase inhibitor may be helpful for men with epilepsy and sexual dysfunction due to testosterone deficiency.

The sexual and reproductive health in men with generalized epilepsy: a multidisciplinary evaluation

This study was specifically aimed to evaluate the sexual and reproductive health in a group of men with generalized epilepsy. In total, 44 men with generalized epilepsy were included in this study, their ages between 18 and 48 years (29.2+/-9.9) and duration of illness between 2 and 35 years (11.2+/-7.4); 34 patients were treated with conventional antiepileptic drugs (AEDs). Sexological and psychological interviews together with serum total testosterone, E(2), FSH, LH and prolactin were determined. Hyposexuality was diagnosed in 61.4%. Erectile dysfunction (ED) and premature ejaculation represented 70.4 and 66.7%, respectively. Variables such as hyposexuality, seizure duration and its poor control on AEDs were significantly associated with depressive symptoms. Compared to the normal control group, all patients reported elevated E(2) levels (P<0.001), 10 had FSH (n=4) and LH (n=6) levels exceeding that of the normal range for controls and two had hyperprolactinemia. Although the patients' mean value of total testosterone remained within the normal range, but it was significantly lower in hyposexual men compared to nonhyposexual (P<0.002), only two epileptic patients had markedly reduced level of total testosterone beyond normal control levels. This study strongly supports that: (1) The risk of hyposexuality and reproductive disturbances is high in epileptic patients with GTC convulsions despite the AEDs utilized. The risk for SD is further increased by poor seizure control and the frequently accompanied depressive manifestations. (2) It is possible that elevated E2 could increase the risk of SD by reducing active testosterone through negative feedback and the reduction of active testosterone could increase seizure intractability to antiepileptic medications.

Anticonvulsant activity of androsterone and etiocholanolone

PURPOSE

Men with epilepsy often have sexual or reproductive abnormalities that are attributed to alterations in androgen levels, including subnormal free testosterone. Levels of the major metabolites of testosterone-androsterone (5alpha-androstan-3alpha-ol-17-one; 5alpha,3alpha-A), a neurosteroid that acts as a positive allosteric modulator of GABA(A) receptors, and its 5beta-epimer etiocholanolone (5beta-androstan-3alpha-ol-17-one; 5beta,3alpha-A)-also may be reduced in epilepsy. 5alpha,3alpha-A has been found in adult brain, and both metabolites, which also can be derived from androstenedione, are present in substantial quantities in serum along with their glucuronide and sulfate conjugates. This study sought to determine whether these endogenous steroid metabolites can protect against seizures.

METHODS

The anticonvulsant activity of 5alpha,3alpha-A and 5beta,3alpha-A was investigated in electrical and chemoconvulsant seizure models in mice. The steroids also were examined for activity against extracellularly recorded epileptiform discharges in the CA3 region of the rat hippocampal slice induced by perfusion with 55 microM 4-aminopyridine (4-AP).

RESULTS

Intraperitoneal injection of 5alpha,3alpha-A-protected mice in a dose-dependent fashion from seizures in the following models (ED50, dose in mg/kg protecting 50% of animals): 6-Hz electrical stimulation (29.1), pentylenetetrazol (43.5), pilocarpine (105), 4-AP (215), and maximal electroshock (224). 5beta,3alpha-A also was active in the 6-Hz and pentylenetetrazol models, but was less potent (ED50 values, 76.9 and 139 mg/kg, respectively), whereas epiandrosterone (5alpha,3beta-A) was inactive (ED50, <or=300 mg/kg). 5alpha,3alpha-A (10-100 microM) also inhibited epileptiform discharges in a concentration-dependent fashion in the in vitro slice model, whereas 5beta,3alpha-A was active but of lower potency, and 5alpha,3beta-A was inactive.

CONCLUSIONS

5alpha,3alpha-A and 5beta,3alpha-A have anticonvulsant properties. Although of low potency, the steroids are present in high abundance and could represent endogenous modulators of seizure susceptibility.

Effect of antiepileptic drugs on reproductive endocrine function in individuals with epilepsy

It is well known that epilepsy, antiepileptic drugs (AEDs), and the reproductive system have complex interactions. Fertility is lower in both men and women with epilepsy than in the general population. Moreover, reproductive endocrine disorders are more common among patients with epilepsy than among the population in general. These disorders have been attributed both to epilepsy itself and to use of AEDs. The use of the liver enzyme-inducing AEDs phenobarbital, phenytoin and carbamazepine increases serum sex hormone-binding globulin (SHBG) concentrations in both men and women with epilepsy. Over time, the increase in serum SHBG levels leads to diminished bioactivity of testosterone and estradiol, which may result in diminished potency in men and menstrual disorders in some women, and thus to reduced fertility. Liver enzyme-inducing AEDs also reduce the efficacy of oral contraceptives. Valproic acid medication may have effects on serum androgen concentrations and it reduces serum follicle stimulating hormone levels in men with epilepsy. However, the clinical significance of valproic acid-related reproductive endocrine changes in men is unknown. On the other hand, in women, use of valproic acid appears to be associated with a frequent occurrence of reproductive endocrine disorders characterised by polycystic changes in the ovaries, high serum testosterone concentrations (hyperandrogenism) and menstrual disorders. These disorders are especially common among women who have gained weight during valproic acid treatment. There are some discrepancies regarding the reported occurrence of reproductive endocrine disorders in women taking valproic acid for epilepsy. However, most studies also including patients receiving valproic acid for other reasons than epilepsy, and studies in different non-epileptic animal models, have shown an association between valproic acid medication and hyperandrogenism and related reproductive endocrine disorders. From a practical point of view, the length of the menstrual cycles and bodyweight should be monitored in women with epilepsy after commencement of treatment with valproic acid. A serum testosterone assay is helpful in following the possible biochemical endocrine changes. Ultrasonography of the ovaries (preferably transvaginal) is indicated if clinical assessment and serum testosterone measurement imply that there is a clinically significant valproic acid-related reproductive endocrine problem. That would be the case if the menstrual cycles were irregular or prolonged (usually >35 days) and serum testosterone levels elevated, especially with associated weight gain. The endocrine effects of the new AEDs have not been widely studied. However, it seems they may offer an alternative if reproductive endocrine problems emerge during treatment with the older AEDs.

Epilepsy and erectile dysfunction: a review

The association between epilepsy and erectile dysfunction (ED) has often been described but not clearly defined. This is a review of the literature regarding the current theories on the causes of ED in epilepsy, as well as the evaluation and treatment options available.

Serum Androgen Levels and Testicular Structure during Pubertal Maturation in Male Subjects with Epilepsy

PURPOSE

To evaluate reproductive endocrine function in boys and young men with epilepsy taking an antiepileptic drug in a population-based, controlled study.

METHODS

Seventy patients and 70 controls matched for age and pubertal stage participated in this study. Twenty-eight patients were taking carbamazepine (CBZ); five, lamotrigine (LTG); 12, oxcarbazepine (OXC); and 25, valproate (VPA) as monotherapy for epilepsy. All subjects were examined clinically, and their medical histories were obtained. Serum reproductive hormone and sex hormone-binding globulin concentrations were measured, and testicular ultrasonography was performed.

RESULTS

Serum testosterone levels were within the normal range in young male patients with epilepsy. However, the patients taking VPA had high serum androstenedione levels at all pubertal stages. In prepuberty, their serum androstenedione values were already approximately fivefold compared with the values of the controls (8.7 nM; SD, 4.0 vs. 1.8 nM, SD, 1.0; p < 0.0003), and they were elevated in 64% of the VPA-treated patients compared with none of the other patients, p = 0.0006. Serum sex hormone-binding globulin levels were increased, and serum dehydroepiandrosterone sulfate concentrations decreased in the pubertal patients taking CBZ. The mean testicular volumes did not differ between the patients and the controls.

CONCLUSIONS

CBZ and VPA, but not LTG and OXC, are associated with changes in serum sex-hormone levels in boys and young men with epilepsy. However, the long-term health consequences of these reproductive endocrine changes during pubertal development remain to be established.

DHEAS as a new diagnostic tool

Dehydroepiandrosterone sulfate (DHEAS) is a 19-carbon steroid, situated along the steroid metabolic pathway. It is the most abundant circulating steroid hormone in the body and can be converted to either androgens or estrogens. Their physiological and pathological functions have not yet been fully identified. Serum DHEAS concentrations peak at around age 25 years and then decline steadily over the following decades. Due to its long half-life and high concentration in the blood, the levels of DHEAS remain the same 24 h a day. This makes DHEAS a very interesting new diagnostic tool for both scientific research and clinical diagnostics. Moreover, circulating concentrations of DHEAS can be changed by many factors, such as endogenous production, hormone supplementation, many kinds of drugs, and many types of disease states. As research moves forward to better understand the relationships of DHEAS with health and disease, it is essential that studies should be designed to control for the influence of many factors on serum DHEAS concentrations.

The influence of hormones and pharmaceutical agents on DHEA and DHEA-S concentrations: a review of clinical studies

Low endogenous levels of dehydroepiandrosterone (DHEA) and/or its sulfoconjugated derivative DHEA-S have been associated with diseases such as lupus, cancer, and diabetes. Circulating concentrations of DHEA and DHEA-S resulting from endogenous production or hormone supplementation may also be relevant in psychiatric illness. Drugs may significantly increase or decrease circulating concentrations of these adrenal androgens by various mechanisms. Some agents, such as dexamethasone, affect the HPA axis by inhibiting ACTH and therefore decrease DHEA and DHEA-S concentrations. Central nervous system agents, including carbamazepine and phenytoin, induce the P450 enzymes that metabolize DHEA and DHEA-S and therefore decrease circulating concentrations of these hormones. Danazol alters the ratio between DHEA and DHEA-S by inhibiting sulfatase. As research moves forward to better understand the relationships of these adrenal androgens with health and disease, it is essential that studies be designed to control for the influence of administered pharmaceuticals on DHEA and DHEA-S.

Carbamazepine increases atherogenic lipoproteins: mechanism of action in male adults

Treatment with carbamazepine (CBZ) affects cholesterol concentrations, but little is known about the precise nature and underlying mechanisms of changes in lipoprotein metabolism. We investigated prospectively the effects of CBZ on lipid metabolism in normolipemic adults. In 21 healthy males, lipoprotein and noncholesterol sterol concentrations were measured before and during treatment with CBZ for 70 +/- 18 days. Thirteen subjects underwent kinetic studies of apolipoprotein-B (ApoB) metabolism with the use of endogenous stable isotope labeling. Lipoprotein kinetic parameters were calculated by multicompartmental modeling. Significant increases in total cholesterol, in ApoB-containing lipoproteins [very-low-density lipoprotein (VLDL), intermediate density lipoprotein (IDL), and low-density lipoprotein (LDL)], and in triglycerides, but not in high-density lipoprotein (HDL), were observed. Lipoprotein particle composition remained unchanged. Mean fractional catabolic and production rates of ApoB-containing lipoproteins were not significantly different, although mean production rates of VLDL and IDL were substantially increased (+46 +/- 139% and +30 +/- 97%, respectively), whereas mean production of LDL remained unchanged (+2.1 +/- 45.6%). Cholestanol in serum increased significantly but not the concentrations of plant sterols (campesterol, sitosterol) and the cholesterol precursors (lathosterol, mevalonic acid). There was a significant correlation between the decrease in free thyroxine and the increase in IDL cholesterol. Treatment with CBZ increases mainly ApoB-containing lipoproteins. CBZ seems not to influence endogenous cholesterol synthesis or intestinal absorption directly. The increase is neither related to increased ApoB production nor to decreased catabolism but is rather due to changes in the conversion cascade of IDL particles, most likely as an indirect effect through a decrease in thyroid hormones.

Morphological changes in the testis after long-term valproate treatment in male Wistar rats

Uncertainty exists about the effect of antiepileptic drugs on gonadal function. In females, long-term valproate treatment has been shown to induce endocrine disturbances and an increased number of ovarian cysts. The aim of the present study was to investigate whether valproate can also induce morphological changes in the testis of male animals. In addition, possible morphological changes in the liver, heart, lungs, lymphatic nodes, pancreas, kidney or brain were studied. The carcinogenic implications were evaluated by the measurement of p53. Male Wistar rats were fed perorally with valproate mixture 200 mg kg(-1)(n= 15) or 400 mg kg(-1)(n= 20), or control solution (n= 15) twice daily for 90 days. Serum concentrations measured 4-6 hours after the last dose were 105 and 404 micromol l(-1)in low- and high-dose valproate treated animals respectively. There was a highly significant, 51% decrease (P< 0.001) in testicular weight in the high-dose treated valproate rats with no changes in the other groups. There was widespread testicular atrophy with histologically verified spermatogenic arrest in 15/20 of the high-dose valproate treated animals. No changes in the testis were seen in the low-dose valproate treated rats, nor in the control rats. There were no morphological changes in the other investigated organs. None of the groups showed over-expression of p53. In conclusion, a dose-dependent effect of chronic valproate treatment was found on testicular morphology in rats. Caution must be taken before these results can be applied to humans.

Seizures, hormones and sexuality

Sexual disorders (both hyposexuality and sexual dysfunction) are common in people with epilepsy, occurring in up to two-thirds of patients. However, characteristically, patients do not spontaneously report these problems. Nocturnal penile tumescence testing suggests that the erectile dysfunction has a neurophysiological component. The aetiology remains uncertain but is likely to be multifactorial, involving neurological, endocrine, iatrogenic, cognitive, psychiatric and psychosocial factors. Epilepsy-related factors include the age of onset/duration of epilepsy along with the seizure type and focus. In addition, seizure frequency might be relevant as successful epilepsy surgery can result in an improvement in sexual functioning despite remaining on anticonvulsant medication. Endocrine changes (raised sex hormone binding globulin and reduced free testosterone) have been reported in men with epilepsy, especially when treated with hepatic-enzyme inducing antiepileptic drugs. Studies have not been performed evaluating anticonvulsants that do not induce hepatic enzymes such as lamotrigine. The association between these endocrine changes and hyposexuality is not known. The relationship between seizures, hormones and anticonvulsant medication in women is explored, focusing on issues such as catamenial epilepsy, the menopause, hormone replacement therapy and the polycystic ovarian syndrome. Suggestions for future research and treatment issues are discussed.

Interictal hyposexuality in male patients with epilepsy

The purpose of this study was to compare the serum levels of androgens between hyposexual and non-hyposexual patients with epilepsy. Adult male patients with epilepsy were investigated. Serum levels of testosterone (T) and free-T, estradiol, and sex hormone binding globulin (SHBG) were measured and the free androgen index (FAI) was calculated. While there were no differences between hyposexual and non-hyposexual patients in the serum levels of T, free-T, and estradiol, or to the FAI, the serum levels of SHBG were significantly higher in hyposexual patients than in non-hyposexual patients. Thus, the effects of increased SHBG upon serum levels of testosterone biologically active in patients with epilepsy and hyposexuality were not detected by the methods used in this study. Four (44%) of nine hyposexual patients who were re-evaluated after two years follow-up improved sexual performance. Thus, clinical treatment that results in good seizure control may improve sexual performance in some patients with epilepsy.

Antiepileptic drug therapy and sexual function in men with epilepsy

PURPOSE

To study the effects of antiepileptic drugs (AEDs) on sex hormone levels and sexual activity in a group of men attending a hospital-based epilepsy clinic.

METHODS

One hundred eighteen men being treated with AED therapy, 32 with epilepsy but not receiving AEDs, and 34 controls were recruited. All subjects were aged 18-65 years. Blood (20 ml) was removed for hormone assays, after which each subject completed a validated questionnaire [Sexuality Experience Scores (Frenken and Vennix, 1981)] aimed at exploring the individuals' sexual activity and attitudes to sexual morality.

RESULTS

Men taking carbamazepine (CBZ) only had significantly higher mean sex hormone-binding globulin (SHBG) levels than the control group. The CBZ group also had a significantly lower mean DHEAS concentration than the control, untreated, and sodium valproate (VPA) monotherapy groups. The phenytoin monotherapy group (PHT) had a significantly higher mean SHBG than both the control and untreated groups, and had a significantly higher mean total testosterone (TT) value than the control untreated, CBZ, and VPA groups, and a significantly lower mean DHEAS than the controls, untreated, and VPA groups. Men receiving more than one AED had significantly higher mean SHBG concentrations compared with control, untreated, and VPA groups. In addition, the polytherapy group's mean TT was significantly higher than the control and VPA groups, although its mean DHEAS concentration was lower than the control, untreated, and VPA groups. There were no significant differences between the study groups in mean FT, Budrostenedione (AND), or estradiol levels. But the CBZ, PHT, and polytherapy groups had significantly lower mean free and rogen index (FAI) than the controls. The CBZ group had a lower mean FAI than the VPA group. The polytherapy group had a lower FAI than the untreated group. Sexuality Experience Scores (SES) showed that those men receiving AEDs embraced a stricter sexual morality than the controls and untreated, and expressed greater satisfaction with their marriages than the control and untreated groups.

CONCLUSIONS

Seizure type did not affect SES scores. Multiple regression showed men who had received further education were less accepting of strict sexual morality.

Sexual function in women with epilepsy

PURPOSE

To examine certain aspects of sexual behaviour and attitudes in a group of women with epilepsy using a validated questionnaire (Sexuality Experience Scales), and effects of antiepileptic drugs (AEDs) on sex hormone binding globulin (SHBG), total testosterone (TT), and free testosterone (FT).

METHODS

One hundred ninety-five women all attending a hospital-based epilepsy clinic were recruited. One hundred fifty-nine received AED therapy and 36 women did not. A control group of 48 women was also recruited. All women completed the first two Sexuality Experience Scales (SES 1 and SES 2), and those women in stable heterosexual relationships completed SES 3 and SES 4. At the same time blood was taken for TT and SHBG levels. FT was calculated using the method of Nanjee and Wheeler (22).

RESULTS

Women receiving AED therapy achieved significantly higher SES 1 and SES 2 scores than the rest of the women, suggesting that they adhered to a stricter sexual morality and were less open to psychosexual stimulation than the rest of the women treated. Women in the treated group were less likely to have received further education than the controls, a factor that influences SES 1 and SES 2 scores. There were no significant differences between the three groups on SES 3 or SES 4, with the exception of the orgasmic adequacy (OE) scale of SES 3 where those women in the treated group attained a higher mean score than the controls, suggesting that they found orgasm less satisfying. Women receiving AEDs had significantly higher SHBG and TT than controls and untreated patients. There were no differences in FT between the groups. Those women receiving AEDs also exhibited the expected midcycle rise in FT. There was no significant correlation between FT and the desired frequency of intercourse or enjoyment of it for the three groups.

CONCLUSIONS

Women in the treated group appeared to be more "moral" and less open to sexual approach, but those who had regular partners appeared to desire and enjoy intercourse as much as the control and untreated groups. This could be explained by differences in demographic characteristics of the study groups or be indicative of a bimodal distribution of sexual interest in these women. As FT was within physiological norms for each study group this cannot be cited as a cause for hyposexuality.

Effects of long-term antiepileptic therapy on the catabolism of testosterone

The serum levels of testosterone, sex hormone binding globulin, and free testosterone index were measured in 51 epileptic men (age 18-45) in order to assess the possible effects of antiepileptic drugs on sexual dysfunction. An analytical gas chromatography-mass spectrometry method was developed to assess the urinary excretion of testosterone, epitestosterone, androsterone, etiocholanolone, 11-OH androsterone and 11-OH etiocholanolone and to evaluate if the catabolism of testosterone had been increased. Twenty normal healthy males of similar age, 18-45 years, served as control group. Patients receiving polytherapy (n = 34) or monotherapy with carbamazepine (n = 8) or phenytoin (n = 9) showed higher levels of sex hormone binding globulin and testosterone, and lower levels of free testosterone than did the controls (P < 0.03). Urinary excretion of the metabolites androsterone and 11-OH androsterone was significantly reduced (P < 0.02) in the polytherapy group, while the monotherapy group showed only significant differences (P < 0.02) in the elimination of 11-OH androsterone. Our results suggest that an induction of the hepatic synthesis of sex hormone binding globulin may be the mechanism by which the antiepileptic drugs lower the levels of free testosterone in serum. However, the reduced excretion of androsterone and the normal levels of etiocholanolone show that the antiepileptic drugs do not produce an increase in the main catabolism pathway of testosterone.

Carbamazepine, phenytoin, sex hormones, and sexual function in men with epilepsy

We evaluated the effects of carbamazepine (CBZ) on serum androgen levels and sexual function prospectively for 5 years in 11 men with epilepsy and in 25 patients receiving either CBZ (14 patients) or phenytoin (PHT) (11) monotherapy for > 5 years. Serum sex hormone binding globulin (SHBG) levels increased and free androgen index (FAI) decreased during CBZ treatment, and these changes correlated with duration of CBZ therapy. Similarly, serum SHBG levels increased and FAI values decreased in patients receiving PHT for > 5 years. CBZ and PHT increase serum SHBG levels, leading to decreased FAI. These drug-related hormonal changes may be the primary cause of hyposexuality common in men with epilepsy.

Serum sex hormone levels after replacing carbamazepine with oxcarbazepine

The function of the hepatic P450 enzyme system was evaluated by measuring the kinetics of antipyrine and serum sex hormone levels were determined in 12 male patients with epilepsy during carbamazepine medication, and two and six months after changing their medication to oxcarbazepine. Antipyrine t1/2 increased and antipyrine CL decreased after the change reflecting normalisation of the liver P450 enzyme system function. Serum sex hormone binding globulin levels decreased, and serum dehydroepiandrosterone sulphate increased after the change. The results show that the carbamazepine-associated induction of the liver P450 enzyme system and changes in serum sex hormone balance can be avoided by replacing carbamazepine with oxcarbazepine.

Liver enzyme induction and serum lipid levels after replacement of carbamazepine with oxcarbazepine

We evaluated liver P450 enzyme system induction and serum lipid levels in a prospective follow-up study in 12 male patients with epilepsy after replacing carbamazepine (CBZ) medication with oxcarbazepine (OCBZ). Antipyrine(t1/2) increased and antipyrine(CL) decreased 2 months after the medication was changed, reflecting normalization of liver P450 enzyme system function. Furthermore, serum total cholesterol levels decreased, but serum concentrations of high-density lipoprotein (HDL)-cholesterol and triglycerides (TG) were unchanged. OCBZ may be the preferable antiepileptic drug (AED) with regard to the effects of the medication on lipid metabolism.

Oxcarbazepine: pharmacokinetic interactions and their clinical relevance

Antiepileptic drug (AED) interactions are a common problem during epilepsy treatment. Oxcarbazepine (OCBZ) is a keto homologue of carbamazepine (CBZ) with a completely different metabolic profile. In humans, the keto group is rapidly and quantitatively reduced to form a monohydroxy derivative (MHD), which is the main active agent during OCBZ therapy. MHD is eliminated by renal excretion, glucuronidation and, marginally, by hydroxylation to a diol derivative. This metabolic profile, and in particular the limited involvement of oxidative microsomal enzymes, suggests that OCBZ may have fewer drug interactions compared with traditional AEDs. This possibility has been investigated in experimental studies and, retrospectively, in data obtained from clinical trials. The capacity of OCBZ to induce microsomal enzymes of the P-450 family has mostly been examined by use of antipyrine and CBZ kinetics as markers. The results suggest that OCBZ has little enzyme inducing capacity. In clinical trials in which OCBZ was substituted for CBZ, plasma concentrations of concomitant AEDs were increased, possibly as a consequence of total or partial de-induction. OCBZ interference with other drugs has been evaluated for warfarin, felodipine, and oral contraceptives, three medications strongly influenced by enzyme-inducing AEDs. OCBZ does not modify the anticoagulant effect of warfarin, whereas some reduction in felodipine concentration and a clinically significant reduction of contraceptive drug levels and efficacy were observed. Polytherapy with established AEDs does not significantly modify OCBZ disposition (MHD kinetics); however, available information is not extensive. Finally, the action on OCBZ kinetics of a group of drugs (verapamil, cimetidine, erythromycin, dextropropoxyphene, and viloxazine) known to inhibit the metabolism of some AEDs has been studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe psychosis and the adrenal androgens

Past literature suggests a link between certain psychotic states and adrenal androgen production, including Dehydroepiandrosterone (DHEA). A group of severely psychotic androgenized females, refractory to substantial amounts of neuroleptics, has been identified for whom endocrine testing revealed abnormally high levels of DHEA. A similar group has been identified among the severely psychotic male population. Improvement in psychosis appears to occur as DHEA returns to its normal range using standard low dose Dexamethasone suppression.

Reproductive endocrine considerations and hormonal therapy for men with epilepsy

Androgen deficiency is unusually common among men with epilepsy. It may contribute to reproductive and sexual dysfunction and possibly exacerbate seizure frequency. The most important androgen is testosterone. it exists in the serum in a free form or bound to albumin or sex hormone-binding globulin (SHBG). Free testosterone levels have correlated significantly with measures of potency and sexual interest. The possibility that measures of non-SHBG-bound testosterone may provide a more sensitive assessment of biologically and perhaps clinically significant androgen levels is raised for consideration. Androgen deficiency may result from increased catabolism and binding induced by antiepileptic drugs (AEDs). It is a feature of the reproductive endocrine disorders that are often associated with epilepsy: hypogonadotropic hypogonadism, hypergonadotropic hypogonadism, and functional hyperprolactinemia. It may be a consequence of medication-induced elevations in serum estradiol. Estradiol exerts a potent inhibitory influence on luteinizing hormone secretion and may contribute to premature aging of the reproductive system, both at the level of the testes and the hypothalamus. Testosterone therapy may moderately benefit reproductive and sexual function. Despite its antiseizure effects in animal experiments, however, it has not been reported to improve seizures clinically. One possible explanation is that AEDs that induce enzyme synthesis may enhance the conversion of testosterone to estradiol by aromatase. This possibility is supported by the improved seizure control achieved with the adjunctive use of the aromatase inhibitor testolactone or the antiestrogen clomiphene.

A prospective study of serum sex hormones during carbamazepine therapy

This paper reports the results of a 12-month prospective follow-up study on the effects of carbamazepine (CBZ) medication on serum sex and pituitary hormone concentrations in 21 male patients with recently diagnosed epilepsy. The results of the present study indicate that a change occurs in the androgen balance during CBZ medication in male patients with epilepsy: a rise in serum sex hormone binding globulin levels results in decreased free androgen index values, and dehydroepiandrosterone sulfate serum levels decrease. Serum testosterone and free testosterone levels remain unchanged, but estradiol levels decrease. Serum basal prolactin (PRL) levels remain unchanged, but the PRL responses to thyrotropin-releasing hormone and metoclopramide increase slightly during the first year of CBZ medication. Basal and stimulated serum gonadotropin levels remain unchanged. The clinical consequences of these hormonal changes during CBZ medication call for further studies.

Post-traumatic hypothalamic-pituitary dysfunction presenting with biochemical features of primary hypothyroidism

Two cases of post-traumatic hypothalamic-pituitary dysfunction are described where the primary pathology was shown to be understimulation of the pituitary by hypothalamic hormones. In each case, the biochemical presentation was a low serum thyroxine and elevated TSH concentration mimicking primary hypothyroidism. Treatment with thyroxine before cortisol replacement was not beneficial. In both cases, hydrocortisone therapy alone resulted in a rise in serum thyroxine and fall in serum TSH. Chronic cortisol deficiency may directly impair the thyroid response to TSH, whilst thyroxine appears to exert its feedback primarily at pituitary rather than hypothalamic level.

Lack of enzyme induction with oxcarbazepine (600 mg daily) in healthy subjects

1. Oxcarbazepine (OXC), the 10-keto analogue of carbamazepine (CBZ), has similar anticonvulsant efficacy and possibly improved patient tolerability. Unlike CBZ, it is metabolised by reduction and may not induce hepatic monooxygenase enzymes. 2. Serum concentrations of OXC and its active metabolite 10-OH-carbazepine (10-OH-CZ) were followed after a single 300 mg dose and during and after 300 mg OXC twice daily for 29 doses in eight healthy male volunteers. 3. Antipyrine metabolism, urinary 6-beta-hydroxycortisol excretion, sex hormone binding globulin (SHBG) levels and circulating androgens were measured as indices of hepatic enzyme induction before, during and after treatment with OXC. 4. Elimination half-lives (mean +/- s.e. mean) of 10-OH-CZ were unaltered by 2 weeks' therapy with OXC (before 11.3 +/- 1.1 h; after 13.9 +/- 3 h). Trough plasma concentrations of 10-OH-CZ at steady-state (31 +/- 2.2 mumol l-1) were higher than predicted (16.5 +/- 4 mumol l-1). 5. Antipyrine metabolism, urinary 6-beta-hydroxycortisol excretion, SHBG levels and circulating androgens were unaltered by treatment with OXC. 6. OXC (600 mg daily) does not induce hepatic monooxygenase enzymes and so is likely to have more predictable dose-concentration relationships and to produce fewer physiological and pharmacological interactions than CBZ.

Serum steroid hormones and pituitary function in female epileptic patients during carbamazepine therapy

Ten regularly menstruating women with epilepsy were studied in a 12-month prospective follow-up study to evaluate the short-term effects of carbamazepine (CBZ) on serum sex hormone balance and pituitary function. Thirteen female epilepsy patients receiving long-term CBZ monotherapy (mean medication duration 5.3 years) were also studied. Controls were 17 regularly menstruating healthy volunteers. Untreated patients had higher free testosterone (FT) and luteinizing hormone (LH) serum concentrations than control subjects, whereas the other parameters did not differ between these two groups. However, serum sex hormone binding globulin (SHBG) levels increased and dehydroepiandrosterone sulfate (DHEAS) levels decreased during CBZ treatment. Although calculated free androgen index (FAI) decreased during CBZ therapy, the directly measured FT levels remained unaltered. These changes were found after 2 months and continued after 12 months of CBZ treatment. Moreover, patients with long-term CBZ also had high SHBG levels, low serum DHEAS levels, and low FAI values. Basal LH serum levels decreased during the first year of CBZ treatment and luteinizing hormone-releasing hormone (LH-RH)-stimulated LH concentrations were lower after 2 months of CBZ treatment. Although the serum basal follicle-stimulating hormone (FSH) and prolactin (PRL) levels were unaffected during the first year of CBZ therapy, the LH-RH-stimulated FSH concentrations and metoclopramide (MC)-stimulated PRL concentrations were lower after 12 months of CBZ treatment than before CBZ. Both basal and stimulated gonadotropin and PRL serum levels of long-term CBZ patients were unaffected. No changes were found in estradiol (E2), testosterone (T), or cortisol (C) serum concentrations during short or long-term CBZ treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyposexuality and epilepsy: a community survey of hormonal and behavioural changes in male epileptics

A survey of five group practices in South London identified 60 male patients currently undergoing treatment for epilepsy. Fifty-four agreed to participate in a detailed enquiry into aspects of their sexual activity and behaviour. Anterior pituitary and sex-hormone levels were measured. The epileptic patients were characterized by low levels of sexual activity and interest. Temporal-lobe and non-temporal-lobe epileptics were indistinguishable in these respects, but when the latter group was further subdivided into primary generalized epilepsy and focal non-temporal lobe epilepsy, the focal groups (both temporal lobe and non-temporal lobe) were more impaired. Hormonal analysis confirmed earlier hospital-clinic-based reports. In the epilepsy group, plasma free testosterone and percentage free testosterone values were decreased, sex hormone binding globulin, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were increased compared to values in a normal healthy population. As association between the behavioural and hormonal indices of hyposexuality was shown, particularly for LH, but this was less apparent than in previous work.

Effects of carbamazepine on the hypothalamic-pituitary-gonadal axis in male patients with epilepsy: a prospective study

The effects of carbamazepine (CBZ) monotherapy on serum sex hormone levels and on pituitary responsiveness to various stimuli were evaluated in a prospective study with 21 male patients with epilepsy. The serum levels of testosterone (T), free testosterone (FT), sex hormone binding globulin (SHBG), estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and dehydroepiandrosterone sulfate (DHEAS) were assayed, and the free androgen index (FAI) values were calculated for each patient before and after 2-month CBZ treatment. The pituitary PRL, LH, and FSH responses to luteinizing hormone-releasing hormone (LH-RH), thyrotropin-releasing hormone (TRH), and metoclopramide (MC) were also measured before and after CBZ treatment. The baseline serum hormone and SHBG levels were measured and the FAI values calculated in 16 healthy male control subjects of similar age. The mean E2 level was higher in patients before CBZ treatment than in control subjects, and untreated patients had greater variances for FAI values, PRL levels, and LH levels than control subjects. No other significant differences were found between untreated patients and control subjects. The FAI values and DHEAS levels of patients decreased during 2-month treatment with CBZ. The PRL response to MC was higher after CBZ treatment than before. The baseline levels of other hormones and SHBG, as well as the LH and FSH responses to LH-RH, remained unaltered. The results indicate that during the first 2 months of CBZ treatment the androgen balance in male epileptic patients changes: Serum DHEAS levels and FAI values decrease, although FT levels remain unchanged. The clinical relevance of these hormonal changes is obscure.

A hypothesis to integrate partial seizures of temporal lobe origin and reproductive endocrine disorders

Recent demonstrations of an association between reproductive endocrine disorders and partial seizures of temporal lobe origin (TLE) have led to the following hypothesis: (1) TLE may promote the development of reproductive endocrine disorders, (2) reproductive endocrine disorders may promote the development of epileptic discharges, and (3) TLE and associated reproductive endocrine disorders may represent the parallel effects of prenatal factors which are common to the development of both the brain and the reproductive system. This article focuses on clinical and animal investigative data that form the basis of this hypothesis.

Effects of carbamazepine therapy on serum sex hormone levels in male patients with epilepsy

The effects of carbamazepine (CBZ) therapy and epilepsy on sex hormone plasma levels in male patients with epilepsy were evaluated by measuring the levels of testosterone (T), free testosterone (FT), sex hormone binding globulin (SHBG), estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and dehydroepiandrosterone sulfate (DHEAS) and by calculating the free androgen index (FAI) in 23 male patients with epilepsy receiving CBZ medication, in 18 untreated male patients with epilepsy, and in 19 healthy age-matched control subjects. No significant differences in the mean T or FT levels were found between the three groups, but the CBZ-treated patients had significantly higher SHBG levels and their FAI values and DHEAS concentrations were lower. The LH, FSH, PRL, or E2 levels in CBZ-treated and untreated male patients with epilepsy did not differ from the controls. CBZ monotherapy does not significantly change the serum balance of sex hormones; however, CBZ clearly affects the serum levels of SHBG and DHEAS.

Circulating hormones and pituitary responsiveness in young epileptic men receiving long-term antiepileptic medication

Impairment of libido and sexual potency are commonly reported by male epileptic patients. This may be partly a consequence of medication. Circulating hormones were measured in 53 postpubertal male epileptic patients less than 45 years of age and in an age-matched control group (n = 40), consisting of 14 untreated epileptic patients and 26 unmedicated healthy subjects. A subgroup also underwent a combined gonadotrophin- and thyrotrophin-releasing hormone (LH-RH/TRH) pituitary stimulation test. Untreated patients did not differ from healthy subjects for any parameter, and their data were combined for comparison with the treated epileptic patients. Total testosterone (T), androstenedione, and basal follicle-stimulating hormone concentrations were similar in all patient groups. Patients receiving more than one drug had higher sex hormone binding globulin (SHBG) (p less than 0.01) and lower free T and dehydroepiandrosterone sulphate (DHAS) levels (both p less than 0.001) than controls. Carbamazepine (CBZ) monotherapy also reduced free T (p less than 0.05) and DHAS (p less than 0.001) and increased basal prolactin (p less than 0.01). In these two groups of patients, basal luteinising hormone (LH) was elevated (p less than 0.01), presumably as a pituitary response to increased T catabolism. There was a negative correlation between free T and circulating CBZ (r = -0.54, p less than 0.05) in the monotherapy patients. Phenytoin (PHT) was associated with a rise in SHBG (p less than 0.01) and a fall in DHAS (p less than 0.001). Basal LH was also elevated, but this just failed to reach statistical significance (p less than 0.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Direct radio-immunoassay of renin substrate: effect of converting enzyme inhibition

A direct radio-immunoassay (RIA) for renin substrate (RS) was compared to the enzymatic (indirect) assay, which measures intact RS only, whereas a direct assay measures both intact RS and des-angiotensin I-RS. In normal subjects, a significant, albeit weak, correlation between the methods was noticed. In hypertensive patients with different levels of plasma renin activity (PRA), RS concentration measured by both assays increased with increasing PRA, and for patients with PRA greater than 10 micrograms AI/l/h, the direct assay gave significantly higher RS values (55%), compared to the enzymatic assay. This indicates consumption of RS by increasing plasma renin and increasing production rate of RS with increasing PRA, of potential importance in the pathogenesis of hypertension. In 11 patients with renovascular hypertension, treatment with the angiotensin-converting enzyme (ACE) inhibitor, lisinopril, resulted in a significant increase in PRA, accompanied by a decrease in RS measured by the enzymatic assay. Lowered plasma RS concentration, by reduction of the velocity of the renin-RS reaction, will distort and invalidate results of PRA determination during treatment with ACE inhibitory compounds. No change in RS measured by direct RIA was noticed, however. The results suggest that ACE inhibition may not have an effect upon RS production and that its effect on plasma RS is limited to a reduction of intact RS measured by the enzymatic assay.

Carbamazepine and ethanol elicited responses in rodents

The interaction between carbamazepine, and anticonvulsant with clinical efficacy in alcohol withdrawal syndrome, and ethanol was studied in rodents. Voluntary intake of ethanol by the rat was the behavioral performance test used to assess one aspect of such interaction. Carbamazepine, 50 mg/kg, IP, caused aversion to ethanol drinking. The drug was devoid of action on rat hepatic ethanol and acetaldehyde metabolizing enzymes, i.e., alcohol- and aldehyde dehydrogenase, and on testicular aldehyde dehydrogenase. The moderate induction of the latter by prolonged ethanol consumption was antagonized by a single dose of carbamazepine (50 mg/kg). Administration of carbamazepine, 50 mg/kg twice daily for three consecutive days, moderately inhibited mouse liver alcohol dehydrogenase in the male but not in the female mouse. This treatment did not alter endogenous mouse cardiac lactate dehydrogenase isoenzymes or hepatic aldehyde dehydrogenase in either sex. The enzymatic portion of the study suggests species and sex differences in the effects of carbamazepine studied. The reduction of voluntary drinking of ethanol by carbamazepine may have clinical implications, e.g., the extension of its use in alcohol withdrawal phase to alcohol abstinence.