[Complete atrioventricular block during lithium therapy within therapeutic range]. / Kompletter AV-Block unter Lithiumtherapie im therapeutischen Bereich.

HISTORY AND CLINICAL FINDINGS: A 69-year-old man came to the emergency unit because of vertigo and presyncope. A bipolar disorder - known since an age of 15 years - has been treated with 2 × 450 mg lithium and 100 mg perazine per day for several years (no other medications). With the exception of a low heart rate (36/min) clinical examination findings were unremarkable. INVESTIGATIONS: Electrocardiography revealed a permanent complete atrioventricular block with a heart rate of 36/min. Echocardiography showed a normal left ejection fraction (EF 65 %). Laboratory tests were mainly unremarkable, particularly the lithium levels (0,7 mmol/l) were within the therapeutic range. TREATMENT AND COURSE: Continuous treatment with orciprenaline stabilized the heart rate at an average of 52/min. After pacing with a provisional pacemaker a permanent pacemaker was implanted without complications, and the symptoms of vertigo and dizziness disappeared. Pacemaker checkup on the following day still showed a complete atrioventricular block with a heart rate of 28/min. CONCLUSION: Complete atrioventricular block secondary to chronic lithium therapy even in therapeutic levels is a rare complication with poor prognosis. Therefore it should be treated consequently.

[Testosterone and the metabolic syndrome]. / Testosteron und das metabolische Syndrom.

Abdominal obesity as a key cardiovascular risk factor as well as metabolic syndrome and type 2 diabetes mellitus are associated with low testosterone levels. In line with these facts, investigations of patients undergoing androgen ablation therapy for prostate cancer have shown a negative effect of this treatment approach on insulin sensitivity and body fat mass. The effects of physiological doses of testosterone seem to have less impact on the parameters of lipid metabolism. However, supraphysiological levels of testosterone can lower HDL levels. At present data on glycemic control in patients with type 2 diabetes are not yet uniform, but negative effects on glycemic control in type 2 diabetics have not been reported. In fact two studies were able to demonstrate a positive effect of testosterone on glycemic control in patients with type 2 diabetes. It is currently not yet possible to conclusively evaluate the significance of testosterone treatment in patients with metabolic syndrome and type 2 diabetes mellitus. Only larger, randomized prospective trials will show whether testosterone therapy is helpful in metabolic syndrome or type 2 diabetes. However, administration of testosterone in hypogonadal men with metabolic syndrome appears to be a promising treatment option to improve metabolic control.

Comparison of long-acting testosterone undecanoate formulation versus testosterone enanthate on sexual function and mood in hypogonadal men.

OBJECTIVE: To compare the effects of two treatment modalities of testosterone on sexual functioning and mood. Design Forty men were randomized to receive either parenteral testosterone enanthate (TE) or long-acting parenteral testosterone undecanoate (TU) over a period of 30 weeks. Thereafter, 20 men who had received TU and 16 men who had received TE continued with TU and completed another 65 weeks to study longer-term effects of TU. METHODS: The following variables of sexual functioning were studied: sexual thoughts and fantasy, sexual interest and desire, satisfaction with sex life, number of erections and ejaculations per week, and number of spontaneous morning erections per week. Also variables related to mood were analyzed. RESULTS: Improvements in these variables were significant and were of a similar magnitude in the group treated with TU and TE for 30 weeks. Improvements were maintained at the same levels over a period of another 65 weeks when all men received TU. Effects on mood were recorded for 30 weeks, but were more difficult to establish in the study population. There were significant differences in baseline values between the two groups and scores showed wide s.d. CONCLUSIONS: Both TE and TU were effective in improving sexual functions in hypogonadal men. An advantage of TU over TE is its lower frequency of administration and its better tolerability and safety profile.

Comparison of a new long-acting testosterone undecanoate formulation vs testosterone enanthate for intramuscular androgen therapy in male hypogonadism.

OBJECTIVE: To assess the efficacy and safety of a novel long-acting im testosterone undecanoate (TU) formulation in comparison with testosterone enanthate (TE). SUBJECTS AND METHODS: An open-label, randomized, prospective clinical trial in 40 hypogonadal men (baseline serum testosterone levels <5 nmol/l), randomly assigned to 250 mg TE/3 weeks (no.=20) or 1000 mg TU im every 6 to 9 weeks for 30 weeks (no.=20). Subsequently, 32/40 men continued the study for another 114 weeks, now receiving TU 1000 mg/12 weeks. RESULTS: TU and TE produced no statistically significant improvements in grip strength over the first 30 weeks, which only occurred after approximately 90 weeks when all subjects received TU. There were no changes in body mass index with TU and TE, neither in the follow-up period when all patients received TU. But ratios of waist to hip circumferences declined in the longer term. Total serum cholesterol, LDL cholesterol, and triglycerides declined over the first 30 weeks, while plasma HDL also declined. Plasma LDL decreased further under long-term TU therapy, while HDL then increased. Hemoglobin and hematocrit values significantly increased over the first 30 weeks in both treatment groups and then no further increase was observed. Levels did not exceed the upper limit of normal. In both treatment groups, serum prostate specific antigen levels rose slightly after 30 weeks, with no further increase over the first 12 months, remaining stable within the normal range. Plasma T before the following TU injection was above the lower limit of reference values. Four injections per year are adequate. CONCLUSIONS: Administration of TU every 12 weeks is at least as safe and efficacious for treatment of hypogonadal men as TE, with a substantially lower frequency of administration. Follow-up over 114 weeks, when all subjects received TU, showed an excellent profile of efficacy and safety.

A four-year efficacy and safety study of the long-acting parenteral testosterone undecanoate.

INTRODUCTION: This is a four-year follow-up of 25 men who received parenteral testosterone undecanoate (TU), 1000 mg every 12 weeks for at least four years. This study was a continuation of a 30-week study wherein the effects of TU had been compared to those of parenteral testosterone enanthate. METHODS & RESULTS: Plasma testosterone (T) trough values of the injection interval of 12 weeks): median 11.9 - 15.9 nmol/L (N 10.0-30.0). E2 and SHBG were stable. Body weight, BMI, waist-to-hip ratio remained stable. Total cholesterol, and triglycerides were unchanged but plasma LDL declined while HDL, after an initial reduction over the first 30 weeks, had increased significantly after three years. Leptin levels, bone mineral density, blood pressure, liver function tests, haemoglobin and haematocrit levels remained stable without values above the upper limit of normal. Over the first 12 months of the study there was an increase in prostate volume from 19.7 +/- 8.8 mL to 22.0 +/- 8.4 mL (p < 0.05) but thereafter volumes remained stable, paralleled by an increase in PSA from 0.67 +/- 0.38 microg/dL to 0.75 +/- 0.35 microg/dL (p < 0.05) without any further changes after 12 months. CONCLUSION: TU appears to be a stable and safe treatment modality of hypogonadal men.

[LOH (late-onset hypogonadism) or the "aging male"]. / LOH (late onset hypogonadism) oder "aging male".

Due to lacking evidence of the data about testosterone deficiency of the aging male or LOH (late-onset hypogonadism), this subject is still a challenge for urologists, endocrinologists, and dermatologists or andrologists. This challenge faces basic research as well as clinical investigations. We have to accept responsibility for solving this challenge to better understand and better treat our patients beyond the scope of current guidelines.

Late-onset hypogonadism in the aging male (LOH): definition, diagnostic and clinical aspects.

Late-onset hypogonadism (LOH) is defined by reduced serum testosterone levels (either total testosterone or free testosterone) and the careful exclusion of any form of classical hypogonadism. When the androgen decline associated with advancing age causes detrimental physiological and mental effects, the syndrome is known as symptomatic LOH (SLOH). A detailed medical history and physical examination are the bases of the diagnosis, and should always precede any biochemical investigations. A general screening of men above a certain age for testosterone deficiency is not feasible. Questionnaires may assist in identifying men who suffer from LOH. Common clinical symptoms of SLOH are lethargy, fatigue, decreased sense of well-being, reduced physical and mental activity, diminished libido, increased sweating, depressive mood, reduced muscle and bone mass or even osteoporosis, erectile dysfunction, and mild anemia. When clinical symptoms are present, the laboratory work-up should focus on total testosterone serum levels. Total testosterone levels <200 ng/dl indicate hypogonadism. In cases of testosterone levels between 200 and 400 ng/dl, measurement should be repeated and supplemented by determination of free testosterone, either by appropriate laboratory methods or the calculation of free testosterone index. In case of very low testosterone levels, classical secondary hypogonadism needs to be considered and excluded. For the safety reasons to exclude contraindications of therapy with androgens, and for follow-up investigations during therapy prostate-specific antigen (PSA), hemoglobin and hematocrit are of interest.

The current status of therapy for symptomatic late-onset hypogonadism with transdermal testosterone gel.

For over 50 years, testosterone therapy has been used for the treatment of hypogonadism. In recent years, there has been an increase in the use of testosterone therapy for men with late-onset hypogonadism, as more convenient and effective modes of application are developed. Testosterone therapy in these men can significantly improve their sense of well-being, and lead to increases in muscle and bone mass, upper body strength, virility and libido [Gruenewald, Matsumoto. J Am Geriatr Soc 2003;51:101; Morales. Aging Male 2004; in press]. However, ensuring that optimal testosterone therapy is achieved in men with hypogonadism remains challenging. Oral delivery of unmodified testosterone is not possible, due to rapid first-pass metabolism and its short half-life. Therefore, different derivatives and formulations of testosterone have been developed to enhance potency, prolong duration of action or improve bioavailability. In addition, several different routes of administration have now been evaluated, including intramuscular injections, oral formulations, transdermal patches, transbuccal systems and transdermal testosterone gel. Despite the broad range of testosterone therapy on offer, each form has its benefits and limitations, and some will suit one patient more than another. An important concern among clinicians is that testosterone therapy may cause or promote prostate cancer. While current evidence supports the safety of testosterone therapy, androgens are growth factors for pre-existing prostate cancer. Therefore, before therapy is initiated, careful digital rectal examination and determination of prostate-specific antigen (PSA) in serum should be performed, in order to exclude evident or suspected prostate cancer. The first 3-6 months after initiating testosterone therapy is the most critical time for monitoring effects on the prostate. Therefore, it is important to monitor PSA levels every 3 months for the first year of treatment; thereafter, regular monitoring (mostly for prostate safety but also for cardiovascular and haematological safety) during therapy is mandatory.

Intramuscular testosterone undecanoate: pharmacokinetic aspects of a novel testosterone formulation during long-term treatment of men with hypogonadism.

In an open-label, randomized, prospective trial, we investigated pharmacokinetics and several efficacy and safety parameters of a novel, long-acting testosterone (T) undecanoate (TU) formulation in 40 hypogonadal men (serum testosterone concentrations < 5 nmol/liter). For the first 30 wk (comparative study), the patients were randomly assigned to receive either 10 x 250 mg T enanthate (TE) im every 3 wk (n = 20) or 3 x 1000 mg TU im every 6 wk (loading dose) followed by 1 x 1000 mg after an additional 9 wk (n = 20). In a follow-up study, observation continued in those patients who completed the comparative part and opted for TU treatment (8 x 1000 mg TU every 12 wk in former TU patients and 2 x 1000 mg TU every 8 wk plus 6 x 1000 mg every 12 wk in former TE patients) for an additional 20-21 months. Here we report only the pharmacokinetic aspects of the new TU formulation for the first approximately 2.5 yr of treatment. At baseline, serum T concentrations did not significantly differ between the two study groups. In the TE group, mean trough levels of serum T were always less than 10 nmol/liter before the next injection, whereas in the TU group, mean trough levels of serum T were 14.1 +/- 4.5 nmol/liter after the first two doses (6-wk intervals) and 16.3 +/- 5.7 nmol/liter after the 9-wk interval at wk 30. The mean serum levels of dihydrotestosterone and estradiol also increased in parallel to the serum T pattern and remained within the normal range. In the follow-up study, the former TU patients (n = 20) received eight TU injections at 12-wk intervals, and the TE patients (n = 16) switched to TU and initially received two TU injections at 8-wk intervals (loading) and continued with six TU injections at 12-wk intervals (maintenance). This regimen resulted in stable mean serum trough levels of T (ranging from 14.9 +/- 5.2 to 16.5 +/- 8.0 nmol/liter) and estradiol (ranging from 98.5 +/- 45.2 to 80.4 +/- 14.4 pmol/liter). The present study has shown that 1000 mg TU injected into male patients with hypogonadism at 12-wk intervals is well tolerated and leads to T levels within normal ranges, using four instead of 17 or more TE injections per year. An initial loading dose of either 3 x 1000 mg TU every 6 wk at the beginning of hormone substitution or 2 x 1000 mg TU every 8 wk after switching from the short-acting TE to TU were found to be a adequate dosing regimens for starting of treatment with the long-acting TU preparation.

Testosterone therapy--what, when and to whom?

Testosterone therapy has been used for more than 60 years in the treatment of male hypogonadism. The classical forms of hypogonadism are comprised of primary testicular failure or insufficient testicular stimulation due to the lack of pituitary gonadotropins. Typical causes of primary hypogonadism are Klinefelter's syndrome, anorchia or acquired disturbances of testicular function. Secondary hypogonadism is characterized by insufficient production of pituitary gonadotropins, due either to pituitary failure or defects at the hypothalamic level. It is unequivocally accepted in clinical practice that any male with inadequately low testosterone production for his age will require androgen therapy. In addition to the classical forms of hypogonadism, the past decade of research has clearly demonstrated that, with increasing age, many men will suffer from decreasing testosterone production. About 15-25% of men over the age of 50 years will experience serum testosterone levels well below the threshold considered normal for men between 20 and 40 years of age. Studies substituting testosterone in elderly men with low serum testosterone have shown that men with clinical symptoms identical to the symptomatology of classical hypogonadism will benefit most from such therapy. Therefore, it is the general consensus to treat men with age-related hypogonadism only when clinical symptoms are present that can be potentially corrected by testosterone administration. Until recently, intramuscular injections of esters, such as testosterone enanthate, have been the mainstay of testosterone therapy. The introduction of testosterone patches has not challenged this approach, since many users of patches suffer from moderate to severe skin reactions. Some oral testosterone formulations have proven to be problematic, as absorption can be variable, bioavailability is frequently poor, due to the first-pass effect of the liver, and frequent administration is often required. Oral testosterone undecanoate avoids, at least partially, the first-pass effect of the liver. However, plasma testosterone levels generally undergo large fluctuations. The large fluctuations in serum testosterone levels caused by conventional intramuscular injections result in unsatisfactory shifts in mood and sexual function in some men, which, combined with the frequency of injections, make the intramuscular mode of delivery far from ideal. Recently, a hydroalcoholic gel containing 1% testosterone has proven to be as efficient as a testosterone patch, but with fewer side-effects and a higher grade of patient satisfaction. Doses of 50-100 mg gel applied once daily on the skin deliver sufficient amounts of testosterone to restore normal hormonal values and correct the signs and symptoms of hypogonadism. The gel has been shown to be effective and successful in patients in the United States, who have benefited from its availability for almost 3 years. In the near future, intramuscular injections of testosterone undecanoate will become commercially available. Such injections have a very favorable pharmacokinetic profile, with one injection every 3 months maintaining serum testosterone well within the normal range. In phase III studies, intramuscular testosterone undecanoate proved to be as efficient as testosterone enanthate, with only one-quarter of the number of injections required and more stable serum testosterone levels. Thus, the new application modes--hydroalcoholic gel (for example, Testogel, Schering AG, Germany) and intramuscular testosterone undecanoate (Nebido, Schering AG, Germany)--appear to be the methods of choice in the near future, one being very suitable for hormone therapy in elderly men, the other for long-term substitution in classical forms of hypogonadism.

Testosterone supplementation: what and how to give.

Several epidemiological studies have demonstrated a gradual decrease of serum testosterone with aging in men. A considerable number of men will experience hypogonadal androgen levels, defined by the normal range for young men. Thus, in addition to the long-standing use of androgen replacement therapy in the classical forms of primary and secondary hypogonadism, age-associated testosterone deficiency has led to considerable developments in application modes for testosterone. Since oral preparations of testosterone are ineffective, due to the first-pass effect of the liver, or, in case of 17 alpha-alkylation, cause hepatotoxicity, intramuscular injection of long-acting esters, such as testosterone enanthate, have been the mainstay of testosterone therapy. However, the large fluctuations of serum testosterone levels cause unsatisfactory shifts of mood and sexual function in some men; combined with the frequent injections, this delivery mode is thus far from being ideal. In contrast, the transdermal testosterone patches are characterized by favorable pharmacokinetic behavior and have proven to be an effective mode of delivery. Safety data over 10 years indicate no negative effect on the prostate. Nevertheless, the scrotal testosterone patch system is hampered by the application site, which is not easily accepted by many subjects; the non-scrotal patch has a high rate of skin irritations. In view of the drawbacks of the currently available preparations, the most recent developments in testosterone supplementation appear to be highly promising agents. Androgen, which has been available in the United States since mid-2000, will be introduced this year in most European markets as Testogel, a hydroalcoholic gel containing 1% testosterone. Doses of 50-100 mg gel applied once daily on the skin deliver sufficient amounts of testosterone to restore normal hormonal values and to correct the signs and symptoms of hypogonadism. The gel has shown to be very effective and successful in American patients, who have benefited from its availability for almost 3 years. Furthermore, in phase II and III clinical studies, the intramuscular injection of 1000 mg testosterone undecanoate every 12-15 weeks has led to extremely stable serum testosterone levels for a prolonged period of time and has resulted in excellent efficacy. It is very likely in the future that these products will be the mainstay of testosterone supplementation. Whereas the indication for testosterone substitution for men with classical forms of hypogonadism is unequivocal, the use of testosterone in men with age-associated hypogonadism is less uniformly accepted. Yet, the few studies addressing this question indicate that men with testosterone serum levels below the lower normal limit for young adult men and with lack of energy, libido, depressed mood and osteoporosis may benefit from testosterone supplementation. However, it should be kept in mind that the experience documented in studies is limited. Nevertheless, serious side-effects, especially in regard to the prostate, did not occur, with the longest study extending over 3 years.

[Assessment of endocrine disorders of the hypothalamic-pituitary axis by nuclear medicine techniques]. / Nuklearmedizinische Verfahren zur Abklärung endokrinologischer Erkrankungen der Hypothalamus-Hypophysen-Achse.

The following article reviews nuclear medicine techniques which can be used for assessment of endocrine disorders of the hypothalamic-pituitary axis. For planar and SPECT imaging somatostatin-receptor- and dopamine-D2-receptor-scintigraphy are the most widely distributed techniques. These nuclear medicine techniques may be indicated in selected cases to answer differential diagnostic problems. They can be helpful to search for presence and localization of receptor positive tissue. Furthermore they can detect metastasis in the rare cases of a pituitary carcinoma. Scintigraphy with Gallium-67 is suitable for further diagnostic evaluation in suspected hypophysitis. Other SPECT radiopharmaca do not have relevant clinical significance. F-18-FDG as PET radiopharmacon is not ideal because obvious pituitary adenomas could not be visualized. Other PET radiopharmaca including C-11-methionine, C-11-tyrosine, F-18-fluoroethylspiperone, C-11-methylspiperone, and C-11-raclopride are available in specialized centers only. Overall indications for nuclear medicine in studies for the assessment of endocrine disorders of the hypothalamic-pituitary-axis are rare. Original studies often report only about a small number of patients. According to the authors' opinion the relevance of nuclear medicine in studies of clinically important endocrinologic fields, e.g. localization of small ACTH-producing pituitary adenomas, tumor localization in ectopic ACTH syndrome, localization of recurrent pituitary tissue, assessment of small incidentalomas, can not be definitely given yet.

Identification of a novel mutation in the arginine vasopressin-neurophysin II gene in familial central diabetes insipidus.

Familial central diabetes insipidus is an inherited disease of predominant autosomal dominant trait characterized by a deficiency of arginine vasopressin. The arginine vasopressin-neurophysin II ( AVP-NPII) gene consists of three exons and is located on chromosome 20p13 encoding for the precursor protein of AVP. We investigated two Caucasian families with a typical autosomal dominant trait of familial central diabetes insipidus, defined by deficiency of arginine vasopressin. After PCR amplification of exon 1 and exon 2/3, fragments were pooled and purified. Nucleotide sequencing was performed with the Taq DyeDeoxy-terminator cycle sequencing method using nested primers. Two mutations in the coding region of NPII were identified. In family C we found a heterozygous G ==> C missense mutation (AA61) in exon 2 leading to the substitution of cystein with serine. In family D a novel heterozygous nonsense mutation in exon 3 (AA 83, GAG ==> TAG) was indentified, leading to a stop codon instead of glutamine. Both mutations were confirmed by restriction analysis and were found in all affected but not in healthy family members or control subjects. We therefore have identified a missense mutation of the AVP-NPII gene and a novel mutation predicting a truncated protein.

First human exposure to FSH-CTP in hypogonadotrophic hypogonadal males.

BACKGROUND: This is the first report of human exposure to the novel compound follicle stimulating hormone (FSH)-C-terminal peptide (CTP) 'FSH-CTP' (Org 36286), a long-acting recombinant FSH like substance, consisting of the alpha-subunit of human FSH and a hybrid beta-subunit. The latter is composed of the beta-subunit of human FSH and the C-terminus part (CTP) of the beta-subunit of human chorionic gonadotrophin (HCG). METHODS: In this phase I, non-blind, multi-centre study, 13 hypogonadotrophic hypogonadal male subjects were enrolled to test the safety of FSH-CTP in terms of antibody formation in humans. Furthermore, the pharmacokinetic profile of this new compound was determined. Subjects were injected four times with 15 microg FSH-CTP with an interval of approximately 4 weeks between each injection. RESULTS: No drug related (serious) adverse events occurred. No antibodies against FSH-CTP or chinese hamster ovary (CHO)-cell derived proteins were detected and measurement of local tolerance demonstrated that s.c. administration of FSH-CTP is well tolerated and no increase in intensity of injection-site responses was observed after repeated exposure to FSH-CTP. After the first and third injection, FSH-CTP serum concentrations were determined. Overall mean (+/- SD) C(max) was 0.426 (+/- 0.116) ng/ml, mean t(1/2) and AUC(0-infinity) were 94.7 (+/- 26.2) h and 81.5 (+/- 18.8) ng.h/ml respectively. Compared with recFSH (Puregon), the half life of FSH-CTP was increased 2-3 times. Following the first and third injection a clear rise in serum inhibin-B concentrations were observed. CONCLUSIONS: The use of FSH-CTP is safe and does not lead to detectable formation of antibodies. Furthermore, the pharmacokinetic and dynamic profile of FSH-CTP may lead to the development of new, more convenient regimens for the treatment of male and female infertility.

Posterior retroperitoneoscopic adrenalectomy: lessons learned within five years.

Posterior retroperitoneoscopic adrenalectomy is one of the new endoscopic methods in endocrine surgery. In a prospective clinical study 142 posterior retroperitoneoscopic adrenalectomies (72 right, 70 left) were performed in 130 patients (52 males, 78 females, age 49.1 +/- 14.9 years). Indications were primary adrenal tumors (unilateral, n = 118; bilateral, n = 2), adrenal metastases (n = 2), and bilateral ACTH-dependent hyperplasias (n = 10). Tumor size ranged from 0.5 to 7.0 cm (mean 2.7 +/- 1.4 cm). Partial adrenalectomies were performed in 39 patients. Conversion to open posterior adrenalectomy was necessary in five patients and seven procedures (5%). Intraoperative and postoperative complications were minor and occurred in 5% and 13%, respectively. Mortality was zero. Operating time was 101 +/- 39 minutes (range 35-285 minutes) and depended on tumor type (pheochromocytoma versus others; p < 0.01), tumor size (< 3 vs. > or = 3 cm; p < 0.05), gender (p < 0.05), and extent of resection (partial versus complete, p < 0.05. Twenty-three adrenalectomies (17%) were performed within 1 hour or less. Blood loss was 54 +/- 72 ml. Consumption of analgesics was low (mean 6 mg piritramide postoperatively). Median duration of hospitalization was 3 days. Posterior retroperitoneoscopic adrenalectomy is a safe method that has become a standard procedure in endocrine surgery.

Vardenafil increases penile rigidity and tumescence in erectile dysfunction patients: a RigiScan and pharmacokinetic study.

The pharmacodynamic effect on penile rigidity and tumescence and the pharmacokinetic properties of single oral doses of 10 and 20 mg vardenafil, a new PDE5-inhibitor, were investigated in 21 erectile dysfunction patients. Patients were evaluated with RigiScan on three occasions in a randomized, placebo-controlled, double-blind crossover fashion, while receiving visual sexual stimulation. Relative to placebo, a single dose of 10 mg vardenafil led to a mean increase in the duration of >60% penile rigidity of 24.4 min (95% CI: 7.4 to 41.3) at the base and of 24.8 min (8.5 to 41.1) at the tip. For the 20-mg dose, the increase in duration of > 60% penile rigidity relative to placebo was 37.2 min (20.2 to 54.1) at the base and 28.7 min (12.7 to 44.7) at the tip. Single doses of 10 and 20 mg vardenafil led to a rapid rise in the plasma concentrations of vardenafil, with a median tmax of 0.9 h and 0.7 h and a geometric mean Cmax of 9.1 microg/l (geometric SD = 1.63) and 20.9 microg/l (geometric SD = 1.83), respectively. In the post-absorptive phase, the concentrations declined with an average terminal t 1/2 of 4.2 h (geometric SD = 1.27) and 3.9 h (geometric SD = 1.31). The systemic exposure of vardenafil expressed as AUC normalized for dose and body weight was dose-proportional (associated 90% CI: -4 to 30%) as well as Cmax (associated 90% CI: -12 to 33%). The treatments were well tolerated. There was a small, clinically irrelevant reduction in blood pressure with a small compensatory rise in heart rate. There were no electrocardiographic effects or relevant changes of the safety laboratory screens. The observed pro-erectile properties, pharmacokinetic characteristics and safety profile make vardenafil a suitable candidate for further evaluation in the treatment of erectile dysfunction.

Increase in G(i alpha) protein accompanies progression of post-infarction remodeling in hypertensive cardiomyopathy.

Hypertensive cardiac hypertrophy and myocardial infarction (MI) are clinically relevant risk factors for heart failure. There is no specific information addressing signaling alterations in the sequence of hypertrophy and post-MI remodeling. To investigate alterations in beta-adrenergic receptor G-protein signaling in ventricular remodeling with pre-existing hypertrophy, MI was induced by coronary artery ligation in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Ten weeks after the induction of MI, the progression of left ventricular dysfunction and increases in plasma atrial natriuretic peptide (ANP) and cardiac ANP mRNA were more pronounced in SHR than WKY. In addition, the impaired contractile response to beta-adrenergic stimulation was observed in the noninfarcted papillary muscle isolated from SHR. Immunochemical G(s alpha) protein and beta-adrenoceptor density were not significantly altered by MI in both strains. However, immunochemical G(i alpha) was increased (1.5-fold) in the noninfarcted left ventricle of the SHR in which infarction had been induced when compared with that in SHR that underwent sham operation. This increase was observed especially in rats with a high plasma ANP level. Furthermore, there was a positive correlation between G(i alpha) and the extent of post-MI remodeling in WKY. A similar correlation between G(i alpha) and the extent of hypertensive hypertrophy was observed in SHR. In conclusion, the vulnerability of hypertrophied hearts to ischemic damage is greater than that of normotensive hearts. An increase in G(i alpha) could be one mechanism involved in the transition from cardiac hypertrophy to cardiac failure when chronic pressure overload and loss of contractile mass from ischemic heart disease coexist.