Sympathoadrenal stress reactivity is a predictor of future blood pressure: an 18-year follow-up study

Salivary alpha-amylase stability, diurnal profile and lack of response to the cold hand test in young women

Salivary cortisol measurement has proved useful for the non-invasive study of the hypothalamic-pituitary-adrenocortical axis, and salivary alpha-amylase has been suggested as a comparable marker for the sympathetic system. Despite some studies showing an increase in salivary alpha-amylase after challenges that stimulate the sympathetic nervous system, questions remain about interpretation. The aims of this study were to explore the stability of salivary alpha-amylase, its diurnal profile, response to the cold hand test, and correlation with cortisol. Salivary alpha-amylase was stable following 5 days at room temperature, and five freeze-thaw cycles. Its diurnal profile was opposite to that of cortisol. There was no salivary alpha-amylase response to the cold hand stress test, in the morning (11am) or afternoon (3pm), unlike cortisol which showed a response in the afternoon in the same samples. There was no correlation between salivary alpha-amylase and cortisol at any time. In conclusion, salivary alpha-amylase is stable to a range of conditions. Its diurnal pattern is compatible with sympathetic stimulation. Lack of response to the cold hand test suggests that secretion of salivary alpha-amylase is controlled by mechanisms more complex than sympathetic regulation alone.

Influence of education and neighborhood poverty on pressor responses to phenylephrine in African-Americans and Caucasian-Americans

Although neighborhood disadvantage has been linked to the development of cardiovascular disease, the mechanism through which living in impoverished neighborhoods is associated with poor cardiovascular health is not well understood. Additionally, it is not clear whether individual socioeconomic status (SES) interacts with neighborhood factors to influence cardiovascular outcomes. Using multilevel modeling, we examined the interaction between neighborhood poverty and individual SES on pressor responses to an alpha agonist, phenylephrine (PE), in an adult sample of 105 African-Americans and 106 Caucasian-Americans. Neighborhood poverty was assessed using census block data gathered from the Census Bureau. Education and occupation were used to assess individual SES. Pressor responsiveness was calculated as the systolic and diastolic blood pressure (BP) response to a 100-microg PE bolus administered intravenously. There was a significant interaction between education and neighborhood poverty on pressor responses. Higher education was associated with smaller BP responses to PE; but only in individuals who lived in neighborhoods in which less than 5% of the residents lived below the poverty line. Occupation was unrelated to pressor responses to PE. These results suggest that neighborhood characteristics play an important role in cardiovascular functioning.

Continuum of phenotypes and sympathoadrenal function in premature adrenarche

OBJECTIVES

Premature adrenarche (PA), the early rise in adrenal androgen (AA) production, can manifest with different clinical signs of androgen effect. Premature pubarche defined as appearance of pubic hair before the age of 8/9 years in girls/boys, is the most prominent clinical sign of PA and often erroneously described as a synonym of PA. Our aim was to determine the association of circulating AA concentrations with different prepubertal signs of androgen action (SAA). Secondly, we tested whether adrenomedullary function is altered in children with SAA, as it is in congenital adrenal hyperplasia (CAH) also causing adrenal hyperandrogenism.

DESIGN AND METHODS

We examined 73 Finnish prepubertal children with any hyperandrogenic sign(s) having appeared before the age of 8/9 years (girls/boys) (35 with pubic and/or axillary hair=PAH; 38 without=nonPAH), and 98 age- and sex-matched controls. Circulating adrenal steroid and catecholamine concentrations were measured and correlated with clinical parameters.

RESULTS

None of the children with SAA had CAH or virilizing tumor. Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione concentrations overlapped between the SAA and control children, and they were lower in the nonPAH than PAH group (P<0.01). SAA children had similar plasma epinephrine but higher norepinephrine (NE) concentrations than their controls (mean (95% confidence interval) 1.61 (1.44, 1.77) versus 1.39 (1.30, 1.49) nmol/l, P=0.03).

CONCLUSIONS

PA forms a continuum with more pronounced increase in circulating androgens in children with PAH than in those without. Some children show SAA with fairly low androgen concentrations. The clinical significance of elevated NE concentrations associated with SAA needs to be confirmed in further studies.