Emad A S Al-Dujaili

Raised salivary testosterone in women is associated with increased attraction to masculine faces.

Womens preferences for masculinity in mens faces, voices and behavioral displays change during the menstrual cycle and are strongest around ovulation. While previous findings suggest that change in progesterone level is an important hormonal mechanism for such variation, it is likely that changes in the levels of other hormones will also contribute to cyclic variation in masculinity preferences. Here we compared womens preferences for masculine faces at two points in the menstrual cycle where women differed in salivary testosterone, but not in salivary progesterone or estrogen. Preferences for masculinity were strongest when womens testosterone levels were relatively high. Our findings complement those from previous studies that show systematic variation in masculinity preferences during the menstrual cycle and suggest that change in testosterone level may play an important role in cyclic shifts in womens preferences for masculine traits.

Men report stronger attraction to femininity in women's faces when their testosterone levels are high

Many studies have shown that womens judgments of mens attractiveness are affected by changes in levels of sex hormones. However, no studies have tested for associations between changes in levels of sex hormones and mens judgments of womens attractiveness. To investigate this issue, we compared mens attractiveness judgments of feminized and masculinized womens and mens faces in test sessions where salivary testosterone was high and test sessions where salivary testosterone was relatively low. Men reported stronger attraction to femininity in womens faces in test sessions where salivary testosterone was high than in test sessions where salivary testosterone was low. This effect was found to be specific to judgments of opposite-sex faces. The strength of mens reported attraction to femininity in mens faces did not differ between high and low testosterone test sessions, suggesting that the effect of testosterone that we observed for judgments of womens faces was not due to a general response bias. Collectively, these findings suggest that changes in testosterone levels contribute to the strength of mens reported attraction to femininity in womens faces and complement previous findings showing that testosterone modulates mens interest in sexual stimuli.

The effect of polyphenol-rich dark chocolate on fasting capillary whole blood glucose, total cholesterol, blood pressure and glucocorticoids in healthy overweight and obese subjects

Numerous studies indicate that polyphenol-rich chocolate reduces fasting blood glucose, blood pressure (BP) and total cholesterol in healthy individuals and hypertensives with or without glucose intolerance. The aim of the present study was to investigate the effect of two doses of polyphenol-rich dark chocolate (DC) on fasting capillary whole blood glucose, total cholesterol and BP and to examine whether improvements in these parameters are associated with changes in adrenocorticoid excretion in overweight and obese individuals. The study used a randomised, single-blind, cross-over design where fourteen overweight and obese subjects were randomised to either take 20 g DC with 500 mg polyphenols then 20 g DC with 1000 mg polyphenols or vice-versa. Participants followed each diet for 2 weeks separated by a 1-week washout period. It was observed that the 500 mg polyphenol dose was equally effective in reducing fasting blood glucose levels, systolic BP (SBP) and diastolic BP (DBP) as the 1000 mg polyphenol dose suggesting that a saturation effect might occur with increasing dose of polyphenols. There was also a trend towards a reduction in urinary free cortisone levels with both groups although it did not reach statistical significance. No changes in anthropometrical measurements were seen. We suggest that more research is required to investigate the mechanism(s) by which polyphenol-rich foods influence health.

Salience of emotional displays of danger and contagion in faces is enhanced when progesterone levels are raised.

Findings from previous studies of hormone-mediated behavior in women suggest that raised progesterone level increases the probability of behaviors that will reduce the likelihood of disruption to fetal development during pregnancy (e.g. increased avoidance of sources of contagion). Here, we tested womens (N=52) sensitivity to potential cues to nearby sources of contagion (disgusted facial expressions with averted gaze) and nearby physical threat (fearful facial expressions with averted gaze) at two points in the menstrual cycle differing in progesterone level. Women demonstrated a greater tendency to perceive fearful and disgusted expressions with averted gaze as more intense than those with direct gaze when their progesterone level was relatively high. By contrast, change in progesterone level was not associated with any change in perceptions of happy expressions with direct and averted gaze, indicating that our findings for disgusted and fearful expressions were not due to a general response bias. Collectively, our findings suggest women are more sensitive to facial cues signalling nearby contagion and physical threat when raised progesterone level prepares the body for pregnancy.

INHIBITION OF THE PLASMA-ALDOSTERONE RESPONSE TO FRUSEMIDE BY BROMOCRIPTINE

The administration of the long-acting dopaminergic agonist bromocriptine to five healthy volunteers inhibited the rise in plasma-aldosterone that normally follows the administration of frusemide. This inhibition was not due to a lowering of plasma-renin activity. It is suggested that dopamine may modulate the normal secretion of aldosterone either directly, or indirectly, possible by inhibition of prolactin secretion.

The development and application of a direct radioimmunoassay for corticosterone

A direct, simple and highly specific radioimmunoassay for corticosterone has been developed. The assay does not require preliminary solvent extraction of the sample or any chromatographic step. The assay utilises a highly specific antibody raised in rabbits against corticosterone-3-(0-carboxymethyl)-oxime-BSA immunogen and gamma-labeled corticosterone of high specific activity. An excellent correlation was obtained between results of the direct assay and those measured after paper chromatography (r = 0.99, P less than 0.001). The coefficients of variation for intra-assay and inter-assay determinations of samples from normal and high plasma pools were 4.6-6.2% and 6.4-8.2% respectively. The minimum limit of detection was 5 pg/assay tube (0.1 ng/ml). The assay has been applied to assess plasma corticosterone levels in various physiopathological and pathophysiological studies. It is extremely practical to the extent that a single technician can assay up to 1000 samples in a working week. Finally, the direct assay has been validated and employed for in vitro adrenal superfusion studies using either rat or human adrenal cells. The large numbers of samples produced by these studies would have exceeded the capacity of earlier radioimmunoassays requiring initial extraction and chromatography.

Water and electrolyte balance in subjects with a permanent ileostomy.

Water and electrolyte balance has been studied in 39 patients with a permanent ileostomy, who had had a proctocolectomy for ulcerative colitis. The findings have been compared with those in 39 healthy subjects who were matched for age and sex. The ileostomists were found to lose excessive quantities of water and sodium in the ileostomy effluent compared with the corresponding losses in normal faeces. The mean plasma total protein and albumin concentrations were increased in the ileostomists suggesting a state of chronic dehydration. The daily urinary output of sodium was low and the output of potassium was high. The urinary pH was low. The ileostomists had raised mean concentration of aldosterone in the plasma (p less than 0.001) and it is suggested that this is responsible for the bodys partial compensation for the depletion of sodium and water, including the so-called ileostomy adaptation.

Differential effect of polyphenol-rich dark chocolate on biomarkers of glucose metabolism and cardiovascular risk factors in healthy, overweight and obese subjects: a randomized clinical trial

The association between excess cortisol and various parameters of metabolic syndrome including hypertension, insulin resistance and dyslipidaemia is increasingly recognised. The present single-blind randomised placebo-controlled cross-over study compared the effect of polyphenol-rich dark chocolate (DC) on biomarkers of glucose metabolism, lipid profile, and blood pressure (BP) in females with BMI ≥ 25 kg m(-2) (n = 21) and females with BMI < 25 kg m(-2) (n = 21). Volunteers consumed 20 g of DC containing 500 mg polyphenols or a placebo DC with negligible polyphenol-content daily for 4 weeks, separated by a 2-week washout period. Systolic BP and diastolic BP decreased after 4 weeks of polyphenol-rich DC. Placebo raised fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and salivary cortisol, an effect that was significantly different from polyphenol-rich DC which had a negligible effect on fasting insulin, HOMA-IR and salivary cortisol. Females with BMI ≥ 25 kg m(-2) responded less favourably to placebo than lean females and consequently had higher fasting insulin and HOMA-IR, in addition to a lower quantitative sensitivity check index (QUICKI) after ingestion of placebo compared to polyphenol-rich DC. No significant changes in lipid profile were observed. This study provides evidence for the metabolic benefits of consuming polyphenol-rich dark chocolate while demonstrating the possibility of adverse effects occurring with polyphenol-poor chocolate placebo.

Hsd11b2 Haploinsufficiency in Mice Causes Salt Sensitivity of Blood Pressure

Salt sensitivity of blood pressure is an independent risk factor for cardiovascular morbidity. Mechanistically, abnormal mineralocorticoid action and subclinical renal impairment may blunt the natriuretic response to high sodium intake, causing blood pressure to rise. 11&bgr;-Hydroxysteroid dehydrogenase type 2 (11&bgr;HSD2) controls ligand access to the mineralocorticoid receptor, and ablation of the enzyme causes severe hypertension. Polymorphisms in HSD11B2 are associated with salt sensitivity of blood pressure in normotensives. In this study, we used mice heterozygote for a null mutation in Hsd11b2 (Hsd11b2+/−) to define the mechanisms linking reduced enzyme activity to salt sensitivity of blood pressure. A high-sodium diet caused a rapid and sustained increase in blood pressure in Hsd11b2+/− mice but not in wild-type littermates. During the adaptation to high-sodium diet, heterozygotes displayed impaired sodium excretion, a transient positive sodium balance, and hypokalemia. After 21 days of high-sodium feeding, Hsd11b2+/− mice had an increased heart weight. Mineralocorticoid receptor antagonism partially prevented the increase in heart weight but not the increase in blood pressure. Glucocorticoid receptor antagonism prevented the rise in blood pressure. In Hsd11b2+/− mice, high-sodium feeding caused suppression of aldosterone and a moderate but sustained increase in corticosterone. This study demonstrates an inverse relationship among 11&bgr;HSD2 activity, heart weight, and blood pressure in a clinically important context. Reduced activity causes salt sensitivity of blood pressure, but this does not reflect illicit activation of mineralocorticoid receptors by glucocorticoids. Instead, we have identified a novel interaction among 11&bgr;HSD2, dietary salt, and circulating glucocorticoids.

Physiological roles of glucocorticoids during early embryonic development of the zebrafish (Danio rerio)

•  Glucocorticoids are known to be present in the developing zebrafish embryo but little is known about their physiological role at this early stage. •  The zebrafish embryo demonstrates a functional glucocorticoid system from around 48 h post fertilisation. •  This system and the stress response is amenable to pharmacological and genetic manipulation in a manner predicted by mammalian physiology. •  Glucocorticoids play a key developmental role in hatching, swimming and stress response. •  The zebrafish embryo is a relevant model for the study of glucocorticoid physiology.