Relationship of leptin and sex hormones to bone mineral density in men.

Sex hormones are strongly associated with bone mineral density (BMD) in adult humans. Leptin, a hormonal product of the OB gene, also appears to be associated with BMD, but results from previous studies are conflicting. Most of the studies in this area have been in women and apparently none have simultaneously analyzed the relationship of estradiol, testosterone, and leptin with BMD in healthy men. To address these issues, serum sex hormones, sex-hormone-binding globulin (SHBG), leptin, dehydroepiandrosterone sulfate (DHEAS), and insulin were measured in 50 apparently healthy men, 18-66 years of age. After controlling for age and body mass index (BMI), BMD correlated positively with estradiol ( p=0.007) and testosterone ( p=0.019), but negatively with leptin ( p=0.001). No significant correlations between BMD and SHBG, DHEAS, or insulin were observed. In multiple regression analysis with age, BMI, estradiol, testosterone, and leptin as the independent variables, only age ( p<0.05), BMI ( p<0.001), and leptin ( p=0.004) were significantly related to BMD. These findings suggest that in men, leptin may have an important negative relationship with BMD.

Preparation, characterization, and the crystal structure of the inhibitor ZK-807834 (CI-1031) complexed with factor Xa.

Factor Xa plays a critical role in the formation of blood clots. This serine protease catalyzes the conversion of prothrombin to thrombin, the first joint step that links the intrinsic and extrinsic coagulation pathways. There is considerable interest in the development of factor Xa inhibitors for the intervention in thrombic diseases. This paper presents the structure of the inhibitor ZK-807834, also known as CI-1031, bound to factor Xa and provides the details of the protein purification and crystallization. Results from mass spectrometry indicate that the factor Xa underwent autolysis during crystallization and the first EGF-like domain was cleaved from the protein. The crystal structure of the complex shows that the amidine of ZK-807834 forms a salt bridge with Asp189 in the S1 pocket and the basic imidazoline fits snugly into the S4 site. The central pyridine ring provides a fairly rigid linker between these groups. This rigidity helps minimize entropic losses during binding. In addition, the structure reveals new interactions that were not found in the previous factor Xa/inhibitor complexes. ZK-807834 forms a strong hydrogen bond between an ionized 2-hydroxy group and Ser195 of factor Xa. There is also an aromatic ring-stacking interaction between the inhibitor and Trp215 in the S4 pocket. These interactions contribute to both the potency of this compound (K(I) = 0.11 nM) and the >2500-fold selectivity against homologous serine proteases such as trypsin.

Association of hyperandrogenemia and hyperestrogenemia with type 2 diabetes in Hispanic postmenopausal women.

OBJECTIVE: Accumulating evidence suggests that hyperandrogenemia may be a risk factor for coronary heart disease (CHD) in women. The present study was carried out to test the hypothesis that hyperandrogenemia is associated with type 2 diabetes in women and thus may contribute to the increased risk of CHD in women with type 2 diabetes. RESEARCH DESIGN AND METHODS: Sex hormones, sex hormone-binding globulin (SHBG), and risk factors for CHD were measured in 20 postmenopausal women with type 2 diabetes and in 29 control subjects. All of the diabetic and control subjects were Hispanic women aged >55 years who were not taking hormone replacement therapy lipid-lowering drugs, or insulin and who were otherwise randomly chosen from a cohort of stroke-free subjects from the Northern Manhattan Stroke Study RESULTS: Mean age, BMI, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, blood pressure, and smoking were not significantly different between cases and control subjects, but waist-to-hip ratio (WHR) was significantly higher in the diabetic subjects (P = 0.01). The mean levels of free testosterone (FT) (P = 0.01), dehydroepiandrosterone sulfate (P<0.04), and estradiol (P = 0.01) (controlled for WHR) were significantly higher in the diabetic subjects; with the statistical outliers removed, the testosterone (P = 0.05) and androstenedione (P = 0.002) levels (controlled for WHR) were also significantly higher in the diabetic subjects. The mean levels of estrone, cortisol, and SHBG were not significantly different. The results were similar in the 10 diabetic subjects treated with diet only Significant positive correlations (controlled for age and BMI) were observed between FT or testosterone and cholesterol, LDL cholesterol, and blood pressure. CONCLUSIONS: Postmenopausal Hispanic women with type 2 diabetes had both hyperandrogenemia and hyperestrogenemia, and testosterone or FT correlated positively with risk factors for CHD. Hyperandrogenemia may be a link between diabetes and CHD in women.

Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry.

Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC ) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC(50) values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (K(d) approximately 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor-heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein-protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED(50) values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies.

Crystallographic analysis of potent and selective factor Xa inhibitors complexed to bovine trypsin.

Factor Xa is a serine protease which activates thrombin (factor IIa) and plays a key regulatory role in the blood-coagulation cascade. Factor Xa is, therefore, an important target for the design of anti-thrombotics. Both factor Xa and thrombin share sequence and structural homology with trypsin. As part of a factor Xa inhibitor-design program, a number of factor Xa inhibitors were crystallographically studied complexed to bovine trypsin. The structures of one diaryl benzimidazole, one diaryl carbazole and three diaryloxypyridines are described. All five compounds bind to trypsin in an extended conformation, with an amidinoaryl group in the S1 pocket and a second basic/hydrophobic moiety bound in the S4 pocket. These binding modes all bear a resemblance to the reported binding mode of DX-9065a in bovine trypsin and human factor Xa.

Serum sex hormone levels in postmenopausal women with hypertension.

In order to test the hypothesis that an alteration in the sex hormone milieu may underlie risk factors for myocardial infarction, fasting serum sex hormones, ie, estradiol, testosterone, free testosterone, and androstenedione, were measured in 24 hypertensive and in 19 healthy postmenopausal women. The mean serum free testosterone level (P=0.01) and the free-to-total testosterone ratio (P < 0.04) were increased in the women with hypertension. In a stepwise multiple regression analysis on the hypertensive and normotensive groups combined, with systolic blood pressure (SBP) as the dependent variable and body mass index, age, free testosterone, estradiol, insulin, and cholesterol levels as the independent variables, only free testosterone showed an independent relationship to SBP (P=0.009). The finding in the present study of an independent positive relationship of free testosterone with hypertension is consistent with a similar relationship of free testosterone with other risk factors for myocardial infarction in women found in previous studies and supports the hypothesis.

Relationship between serum sex hormones and coronary artery disease in postmenopausal women.

Although sex hormones appear to be importantly involved in the development of coronary heart disease, apparently no study has yet reported an alteration in an endogenous sex hormone level in relation to coronary heart disease in women. In an attempt to determine whether any sex hormone abnormality might be a factor in the development of myocardial infarction in women, estradiol and testosterone, as well as sex hormone-binding globulin, insulin, dehydroepiandrosterone sulfate, and risk factors for myocardial infarction, were measured in relation to the degree of coronary artery disease (CAD) in 60 postmenopausal women undergoing coronary angiography. In a multiple-regression analysis with the degree of CAD as the dependent variable and free testosterone (FT), estradiol, age, body mass index, systolic blood pressure, cholesterol, smoking, and insulin as independent variables in the model, only FT (P < .008) and cholesterol (P = .01) were significantly related to the degree of CAD, both positively. To exclude a possible confounding effect due to prior myocardial infarction, the multiple-regression analysis was repeated for the subgroup of 49 patients remaining after excluding the 11 patients who had ever had a myocardial infarction; again only FT (P < .04) and cholesterol (P = .05) were significantly related to the degree of CAD. Neither total testosterone in place of FT nor HDL cholesterol in place of total cholesterol in the model was significantly related to CAD. Sex hormone-binding globulin and dehydroepiandrosterone sulfate, added individually to the model, showed no significant relationship to CAD. These results raise the possibility that in women an elevated FT level may be a risk factor for coronary atherosclerosis.

The association of hyperestrogenemia with coronary thrombosis in men.

Both hyperestrogenemia and hypotestosteronemia have been reported in association with myocardial infarction (MI) in men. It was previously observed that the serum testosterone concentration correlated negatively with the degree of coronary artery disease (CAD) in men who had never had a known MI. The present study investigated the relationship of sex hormone levels to the thrombotic component of MI by comparing these levels in 18 men who had had an MI (ie, thrombosis) and 50 men with no history of MI (ie, no thrombosis) whose degree of CAD was in the same range. The mean degree of CAD, age, and body mass index in these two groups was not significantly different. The mean serum estradiol level in the men who had had an MI (38.5 +/- 8.8 pg/mL) was higher (P = .002) than the level in the men who had not had an MI (31.9 +/- 7.1 pg/mL). The mean levels of testosterone, free testosterone, sex hormone-binding globulin, insulin, dehydroepiandrosterone sulfate, cholesterol, HDI, cholesterol, and systolic and diastolic blood pressure did not differ significantly. Estradiol was the only variable measured that showed a significant relationship to MI (P < .003 by multivariate logistic regression). These findings suggest that hyperestrogenemia may be related to the thrombosis of MI.

Relationship between serum dehydroepiandrosterone sulfate, androstenedione, and sex hormones in men and women.

Previous reports of a correlation between serum dehydroepiandrosterone sulfate (DHEAS) and testosterone in both men and women have led to the suggestion that adrenal and gonadal secretion are related. In the present study, the correlation of DHEAS with testosterone and free testosterone (FT) in both normal men and women was tested. Androstenedione, estradiol, sex hormone binding globulin (SHBG), and insulin were also measured and their correlations determined. All correlations were controlled for age and body mass index. In the men in the study, DHEAS did not correlate with testosterone or FT but correlated strongly with androstenedione. In the women, DHEAS correlated strongly with testosterone, FT, and androstenedione; androstenedione in turn correlated strongly with testosterone and FT. DHEAS showed no correlations with estradiol, SHBG, or insulin in the men or women. The lack of a correlation between DHEAS and testosterone in normal men is consistent with the independent secretion of these hormones by the adrenal and testis, respectively. The finding of a strong DHEAS-testosterone correlation in normal women may be explained by parallel adrenal secretion in response to trophic stimuli, i.e., without invoking an adrenal-gonadal interaction.

Serum sex hormone levels and renin-sodium profile in men with hypertension.

Both a high renin-sodium profile and abnormal levels of sex hormones have been linked to myocardial infarction (MI) in men. The present study was carried out in men with hypertension to determine whether renin-sodium profile and sex hormone levels are related to each other. Renin-sodium profile, estradiol, testosterone, sex-hormone binding globulin (SHBG), and risk factors for MI, ie, cholesterol, insulin, glucose, and blood pressure, were determined in 45 men with hypertension. The mean serum estradiol level of the 13 men with high renin profile (30.1 +/- 6.5 pg/mL) was significantly higher (P = .01) than that of the nine men with low renin profile (22.6 +/- 3.9), while the mean level of the 23 men with normal renin profile was intermediate (26.2 +/- 5.3). The levels of estradiol and plasma renin activity correlated in the 45 patients before (r = 0.48, P = .001) and after (r = 0.46, P = .002) controlling for age. The mean estradiol-to-testosterone ratio was also higher (P = .04) and the mean SHBG level lower (P < .02) in the high renin group, but the mean testosterone level was not significantly different between the high and low renin groups. Although none of the risk factors was significantly different between the high and low renin groups, all of the mean values in the high renin group were in the direction of increased MI risk. These findings suggest that in men with hypertension, renin profile may be related to estradiol level and possibly to risk factors for MI.

The association of hypotestosteronemia with coronary artery disease in men.

Hyperestrogenemia and hypotestosteronemia have been observed in association with myocardial infarction (MI) and its risk factors. To determine whether these abnormalities may be prospective for MI, estradiol and testosterone, as well as risk factors for MI, were measured in 55 men undergoing angiography who had not previously had an MI. Testosterone (r = -.36, P = .008) and free testosterone (r = -.49, P < .001) correlated negatively with the degree of coronary artery disease after controlling for age and body mass index. When the patient group was successively reduced to a final study group of 34 men by excluding the patients with other major disorders, the testosterone and free testosterone correlations persisted (r = -.43, P < .02 and r = -.62, P < .001, respectively). Neither estradiol nor the risk factors, except for high-density lipoprotein cholesterol, correlated with the degree of coronary artery disease in the final group. Testosterone correlated negatively with the risk factors fibrinogen, plasminogen activator inhibitor-1, and insulin and positively with high-density lipoprotein cholesterol. The correlations found in this study between testosterone and the degree of coronary artery disease and between testosterone and other risk factors for MI raise the possibility that in men hypotestosteronemia may be a risk factor for coronary atherosclerosis.

Sex hormones and hemostatic risk factors for coronary heart disease in men with hypertension.

OBJECTIVE AND DESIGN: It has been hypothesized that risk factors for coronary heart disease in men are linked and that the underlying factor linking them may be an alteration in the sex hormone milieu. As a test of this hypothesis, sex hormones and fibrinogen, factor VII and plasminogen activator inhibitor (PAI-1), hemostatic factors recently shown to be risk factors for myocardial infarction, were measured in men with hypertension and in healthy control subjects. RESULTS: The fasting serum testosterone and free testosterone levels were decreased and the plasma factor VII and PAI-1 levels increased in the men with hypertension. CONCLUSION: These findings are consistent with the stated hypothesis.

Relation of hemostatic risk factors to other risk factors for coronary heart disease and to sex hormones in men.

The present study was carried out to explore the possible relation of plasma plasminogen activator inhibitor-1 (PAI-1), fibrinogen, and factor VII levels to other risk factors for coronary heart disease (CHD) and to serum sex hormone levels. The study group comprised 48 apparently healthy men. To avoid the confounding factor of obesity, correlations were determined in the 30 men in this group with a body mass index (BMI) < 26.4, after controlling for age. PAI-1 correlated with testosterone, estradiol/testosterone, and free testosterone/testosterone (FT/T), and fibrinogen correlated with FT/T. All three hemostatic factors correlated with glucose and with the ratio of cholesterol/high density lipoprotein cholesterol, while PAI-1 correlated with diastolic blood pressure. To test the effect of obesity, correlations were determined in the entire group of 48 men, which included 18 subjects with a BMI > 26.4. All three hemostatic factors correlated with BMI in this group after controlling for age; however, on controlling for testosterone, only PAI-1 correlated with BMI. Fibrinogen correlated with age in both groups after controlling for testosterone or BMI. These correlations support the hypothesis that PAI-1, fibrinogen, and factor VII are related to other risk factors for CHD and that an alteration in the sex hormone milieu may be the underlying factor linking them.

Relationship between serum sex hormones and the glucose-insulin-lipid defect in men with obesity.

It has been hypothesized that an alteration in the sex hormone milieu may underlie coronary heart disease (CHD) and its risk factors. Leading to this hypothesis and important to it was the observation that serum testosterone level correlated negatively and the estradiol to testosterone ratio (E/T) correlated positively with serum insulin and glucose levels in non-obese men. As a test of the validity of this observation, the present study was conducted to investigate these correlations in men with obesity. Obesity in men is associated with hyperestrogenemia, hypotestosteronemia, hyperinsulinemia, hyperglycemia, and CHD. To determine whether the relationships between sex hormone levels and insulin and glucose levels found in non-obese men also occur in obese men independent of obesity, fasting levels of these substances, as well as free testosterone (FT) and sex-hormone-binding globulin (SHBG), were measured in 55 obese men aged 21 to 70. Correlation coefficients of sex hormones with other risk factors for CHD, ie, cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), blood pressure, and waist to hip circumference ratio (W/H), were also calculated. As found previously, testosterone level correlated negatively with insulin (r = -.31, P = .01) and glucose (r = -.23, P < .05) levels and the insulin to glucose ratio ([I/G] r = -.26, P < .05), and E/T correlated positively with insulin (r = .41, P = .001) and glucose (r = .24, P < .05) levels and I/G (r = .37, P < .005). The above correlations were controlled for body mass index (BMI) and age.(ABSTRACT TRUNCATED AT 250 WORDS)

The variability of the serum estradiol level in men: effect of stress (college examinations), cigarette smoking, and coffee drinking on the serum sex hormone and other hormone levels.

The results of studies carried out to evaluate the relationship of estradiol to coronary heart disease and its risk factors in men have been conflicting. Three possible causes of these conflicting results are (a) an inherent variability of the estradiol level within individual men; (b) the confounding effects on the estradiol level of certain common exogenous factors such as psychological stress, cigarette smoking, and coffee drinking; and (c) methodology and study design. The present study was conducted to test in men the inherent variability of the serum estradiol level and the effects of psychological stress (college examinations), cigarette smoking, and coffee drinking on the serum estradiol level. Subsets of 41 men, 19-57 years of age, were studied. A highly significant correlation in the estradiol levels was found between two fasting samples taken 30 minutes, 19.1 (mean) days, 2-6 months, and 10-89 months apart. Neither the stress of college examinations nor 30 minutes of cigarette smoking or coffee drinking had any apparent effect on the serum estradiol level, even in the presence of a two- to fivefold increase in the level of other hormones in four subjects with an autonomic reaction (three to smoking and one to venipuncture). It appears that the serum estradiol level is remarkably stable in men when taken under controlled conditions and that neither inherent fluctuation in this level nor the effects of the exogenous factors as studied are responsible for the conflicting results.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, cardiac electrophysiology, and beta-blocking activity of novel arylpiperazines with potential as class II/III antiarrhythmic agents.

A series of novel arylpiperazines have been prepared in an attempt to incorporate both class II (beta-receptor blocking) and class III antiarrhythmic properties in a single molecule. The key step in the preparation of the new compounds involves a regioselective heterocyclic ring formation. All but four compounds significantly prolonged action potential duration in canine cardiac Purkinje fibers (class III activity). All but one of the compounds demonstrated beta-receptor affinity in a competitive binding assay and three had beta 1-receptor selectivity. Compared to sotalol, a reference class II/III agent, arylpiperazine 7a (4-[(methylsulfonyl)amino]-N-[(4- phenylpiperazin-2-yl)methyl]benzamide) demonstrated beta 1-selectivity and was 1 order of magnitude more potent in the in vitro class III and the beta 1-receptor screens. Compound 7a was evaluated further and found to be effective in preventing programmed electrical stimulation-induced arrhythmias in conscious dogs (class III activity) and against epinephrine-induced arrhythmias in halothane anesthetized dogs (class II activity).

Synthesis of novel (aryloxy)propanolamines and related compounds possessing both class II and class III antiarrhythmic activity.

Several (aryloxy)propanolamines and related compounds (i.e. 5-13, 16-18, 20-24, 27-33, 35, 37-39, 41, and 42) were synthesized and investigated for their class III electrophysiological activity and class II (beta-blocking) effects with use of in vitro and in vivo models. Structure-activity relationships are discussed for a series of 30 compounds. A number of these compounds prolonged the action potential duration at 95% repolarization of isolated canine cardiac Purkinje fibers by 20% (C20APD95) at concentrations of less than 1.0 microM, with no significant effects on cardiac conduction. beta-Adrenergic receptor binding studies showed that some of these compounds were 2-20 times more potent for cardiac beta 1 receptors than for beta 2 receptors. In particular, compounds 32, 41, 1, and especially (S)-1 were found to be orally active class III agents in anesthetized mongrel dogs (1 or 3 mg/kg, id) and efficacious at suppressing programmed electrical stimulation induced arrhythmias in halothane-anesthetized dogs. The profile of these compounds was similar to that found for sotalol. Compound (S)-1, which was more potent than sotalol in the PES study and equieffective in the halothane/epinephrine dog model, is being investigated further as a combined class III/II antiarrhythmic agent.