D-aspartate and reproductive activity in sheep.

D-aspartic acid (D-Asp) has been isolated from neuroendocrine tissues of many invertebrates and vertebrates. Recently, it has been demonstrated that this D-amino acid may be converted to N-methyl-D-aspartic acid (NMDA), a neuromodulator associated with sexual activity. In this study, we determined D-Asp and NMDA concentrations in endocrine glands and other tissues in ewes after D-Asp administration and in controls. We also evaluated the effects of d-Asp administration on the reproductive activity of ewes by determining either progesterone concentrations or LH pulses in the presence or absence of estradiol benzoate. The pineal gland showed the highest natural content of D-Asp (1.47+/-0.22 micromol/g tissue), whereas the pituitary gland had the highest capability to store d-Asp, with a peak value (9.7+/-0.81 micromol/g tissue) 6 h after its administration. NMDA increased sharply 12 h following D-Asp administration, reaching values three times higher than the baseline in both the pituitary and brain. D-Asp was quickly adsorbed after subcutaneous administration, with a peak in plasma levels 2 h after administration and a return to baseline values after 6 h. D-Asp administration achieved a significant (P < 0.001) increase in LH values with respect to estradiol or estradiol + D-Asp treatments. d-Asp treatment once or twice a week did not successfully drive acyclic ewes into reproductive activity. In conclusion, the results obtained in this study demonstrated that D-Asp is endogenously present in sheep tissues and electively stored in endocrine glands and brain after its administration. NMDA and LH increase following D-Asp administration suggesting a role of this D-amino acid in the reproductive activity of sheep.

Left ventricular changes in isolated office hypertension: a blood pressure-matched comparison with normotension and sustained hypertension.

BACKGROUND: Isolated office (IO) hypertension is a benign condition according to some researchers, whereas others believe it is associated with cardiovascular abnormalities and increased cardiovascular risk. The aim of this study is to compare morphofunctional characteristics of the left ventricle (LV) in IO hypertensive subjects, normotensive subjects (hereafter, hypertensives and normotensives), and never-treated sustained hypertensives. The 3 groups were matched not only by age, sex, and body mass index but also by clinic blood pressure (BP) (IO hypertensives and sustained hypertensives) and daytime BP (IO hypertensives and normotensives). METHODS: We enrolled 42 IO hypertensives (clinic BP > 140 and/or 90 mm Hg and daytime BP < or = 130/80 mm Hg), 42 sustained hypertensives (clinic BP > 140 and/or 90 mm Hg and daytime BP > or = 140 and/or 90 mm Hg) and 42 normotensives (clinic BP < 135 and/or 85 mm Hg and daytime BP < or = 130/80 mm Hg). Left ventricular morphologic features and function were assessed using digitized M-mode echocardiography. RESULTS: Compared with normotensives, IO hypertensives had significantly thicker LV walls, increased LV mass, reduced diastolic function, increased prevalence of LV hypertrophy, and preclinical diastolic dysfunction. Sustained hypertensives, compared with IO hypertensives, had significantly thicker LV wall, higher LV mass, and lower diastolic function, whereas the prevalence of LV hypertrophy and preclinical diastolic dysfunction was greater than in IO hypertensives, but the difference did not reach statistical significance (P = .29). CONCLUSIONS: Comparing matched BP groups, IO hypertensives have LV morphofunctional characteristics considerably different from normotensives and qualitatively similar to sustained hypertensives. Therefore, our results support the hypothesis that IO hypertension should not be considered as simply a benign condition.

Microalbuminuria as a marker of preclinical diastolic dysfunction in never-treated essential hypertensives.

Using 24-h ambulatory blood pressure (BP) monitoring and digitized M-mode echocardiography, we evaluated whether microalbuminuria is related to preclinical left ventricular (LV) diastolic dysfunction in hypertensive patients. We selected 87 never-treated hypertensive patients (mean 24-h BP > 140 and/or > 90 mm Hg); albuminuria was evaluated as mean value of 24-h urinary albumin excretion (UAE) from two 24-h urine collections. Microalbuminuria was found in 28 patients, classified as MA+ (UAE 30 to 300 mg/24 h); 59 patients had normal UAE (< 30 mg/24 h) and were classified as MA-. The MA+ and MA- groups did not differ with regard to age, sex, body mass index, or 24-h heart rate, whereas 24-h, daytime, and nighttime systolic and diastolic BP were significantly higher in MA+ than in MA-. The LV mass index was greater in MA+, as was the prevalence of LV hypertrophy; peak shortening rate of LV diameter, index of systolic function, was normal in all, but was lower in MA+. Peak lengthening rate of LV diameter and peak thinning rate of posterior wall, indices of diastolic function, were lower in MA+ and the prevalence of diastolic dysfunction was higher in MA+. UAE was inversely correlated with both indices of LV diastolic function, also after correction for age, 24-h heart rate, 24-h BP, and LV mass. In conclusion, in never-treated hypertensive patients, microalbuminuria is not only associated with greater myocardial mass, but is also related with preclinical impairment of LV diastolic function. This relation, independent from increased BP or LV mass, strengthens the role of microalbuminuria as an early and reliable marker of preclinical cardiac involvement.

Microalbuminuria in never-treated hypertensives: lack of relationship to hyperinsulinemia and genetic predisposition to hypertension.

We evaluated the relationship of microalbuminuria to hyperinsulinemia and family history of hypertension in 92 never-treated essential hypertensives (mean 24-h blood pressure >140 or 90 mm Hg), with positive (F+) or negative (F-) family history of hypertension: 31 had microalbuminuria (MA+) (urinary albumin excretion [UAE], 30 to 300 mg/24 h) and 61 had normal (<30 mg/24 h) UAE (MA-). Glucose and insulin values before and 30, 60, 90, and 120 min after an oral glucose load were measured together with an index of peripheral insulin activity (10(4)/ insulin x glucose values at glucose peak). Subjects with and without microalbuminuria did not differ with regard to age, sex, body mass index, and 24-h heart rate, whereas 24-h, daytime, and nighttime systolic and diastolic blood pressure were significantly higher in MA+ than MA- patients. The prevalence of positive family history of hypertension was similar between MA+ and MA-, as were fasting and stimulated glucose and insulin values and the index of peripheral insulin activity. Subdividing the patients on the basis of family history of hypertension (59 F+, 33 F-) UAE was not significantly different between F+ and F-. UAE did not correlate with glucose and insulin parameters. From our results, in never-treated hypertensives, microalbuminuria is associated with higher blood pressure values, but is related neither to genetic predisposition to hypertension, nor to hyperinsulinemia; therefore, impaired insulin sensitivity and microalbuminuria are two components of the hypertensive syndrome, largely independent of each other.

Individualized versus standardized analysis of ambulatory blood pressure profile: relationship with left ventricular characteristics.

OBJECTIVE: Objective To determine whether the use of patients' individual awake/asleep patterns instead of fixed day/night intervals would influence the correlations between blood pressure values and left ventricular morpho-functional characteristics. METHODS: We enrolled 167 never-treated hypertensives (clinic blood pressures >160 mmHg systolic or 90 mmHg diastolic, or both): 32 had 24h blood pressures <130/80 mmHg [white-coat hypertensives (WCH)] and 135 had 24h blood pressures >130 mmHg systolic or 80 mmHg diastolic, or both (hypertensives). Each patient underwent left ventricular echocardiographic examination and 24h ambulatory blood pressure monitoring, evaluated twice, using standard day/night intervals (daytime 0700-2200 h, night-time 2200-0700 h) and using the patient's individual awake/asleep pattern (an individualized scheme). RESULTS: Daytime and night-time blood pressures in WCH and daytime and night-time diastolic blood pressures in hypertensives were not affected by choice of using individualized or standard intervals; daytime systolic blood pressure in hypertensives was significantly higher and night-time systolic blood pressure lower with individualized intervals. The non-dippers (nocturnal decrease in blood pressure <10% of daytime blood pressure) were 31 hypertensives and six WCH with standard day/night intervals and 25 hypertensives and four WCH with individualized intervals; nocturnal falls in systolic and diastolic blood pressures were significantly greater with individualized intervals for both groups. Left ventricular hypertrophy was present in 68 hypertensives and seven WCH; left ventricular systolic function was normal in all and left ventricular diastolic function was impaired in 53 hypertensives and seven WCH. Left ventricular characteristics of WCH were not correlated to blood pressure parameters; left ventricular mass index of hypertensives was directly correlated to 24h, daytime and night-time systolic blood pressures, whereas left ventricular diastolic function was inversely correlated to night-time systolic and diastolic blood pressures. The correlations were not affected by choice of using individual awake/asleep patterns. CONCLUSIONS: Timing day and night in an individualized way seems to improve the evaluation of nocturnal fall in blood pressure, but does not improve the ability to predict the left ventricle's involvement with ambulatory blood pressure monitoring.