Importance of bioavailable calcium drinking water for the maintenance of bone mass in post-menopausal women.

The aim of this research was to establish the importance of calcium intake through mineral water on vertebral bone density in women. To this purpose, we examined 255 women divided into two groups: those regularly drinking a high calcium content mineral water (group A; no.=175) and those using different type of water with a lower calcium content (group B; no.=80). Their dietary daily calcium intake was determined by means of a validated questionnaire (N.I.H. Consensus statement) and vertebral bone density was measured by Dual-Energy X-ray absorptiometry (Unigamma-plus ACN densitometer). Women in group A ingested a significantly higher quantity of calcium in water than women in group B (mean difference 258 mg; 95% confidence limits: 147-370 mg). The average bone density values were slightly but significantly higher in group A as compared to group B (mean+/-SD: 1.044+0,15 vs 1.002+0,14; p=0.03). In addition to age, BMI and menopausal status, calcium intake was a significant predictor of spinal BMD. These 4 variables explained about 35% of the spinal BMD variance. When the analysis was repeated separately for pre- and post-menopausal subjects, calcium remained a significant predictor in post-menopausal women (t=2.28; p=0.02), but not in premenopausal women. These results underline the importance of a lifelong daily calcium intake, resulting by the regular drinking of high bioavailable calcium water, in order to maintain bone mass after the menopause, in comparison to the use of a lower content calcium water.

Lack of ACTH/cortisol and GH responses to intravenously-infused substance P in Parkinson's disease.

In order to test possible changes in the stimulating effect of intravenously-infused substance P (SP) on ACTH/cortisol and GH secretion in Parkinson's disease, 10 male parkinsonian patients and 10 age-matched normal controls were infused intravenously for 60 min with SP (1.0 or 1.5 pmol/kg-1/min-1 SP) or normal saline. The circulating levels of ACTH, cortisol and GH were measured during and for 20 min after SP or saline infusion. No untoward side effects or changes in blood pressure were observed during SP infusion in any subjects. In basal conditions and during saline infusion, plasma ACTH and cortisol levels were similar in normal and parkinsonian patients. During SP infusions, ACTH/cortisol concentrations in normal controls rose significantly vs baseline and saline test in a dose-dependent fashion. In contrast, at both SP infused amounts, parkinsonian patients showed ACTH/cortisol levels similar to those observed in the saline test. All subjects showed similar basal concentrations of GH. GH levels rose significantly in the normal controls when the higher dose of SP was infused, but they were not modified by the infusion of the lower dose of SP or saline. At both tested amounts of SP and during saline infusion, GH levels remained unchanged in the parkinsonian subjects. In agreement with previous observations in the literature showing SP abnormalities in the parkinsonian brain, these data fail to show significant effects of plasma SP on the ACTH/cortisol and GH secretory systems in Parkinson's disease.

Sex-related responses of beta-endorphin, ACTH, GH and PRL to cold exposure in humans.

To establish a possible different reaction between the male and the female to short-term exposure to cold, thermal, cardiovascular and pituitary hormonal responses to cold stress were measured in eight normal men and eight women (ages 19-24). The women were eumenorrheic and were tested in the follicular phase. Each subject, lightly clad, was required to remain for 30 min in a room at an ambient temperature of 25 degrees C followed by a 30 min period in a cold room at 4 degrees C. A month later, control tests were carried out at a constant 25 degrees C temperature for 1 h in the same subjects. Skin temperature, heart rate, blood pressure and plasma levels of beta-endorphin, ACTH, cortisol, GH and PRL were measured before and after cold exposure in the two groups. Before the test, all examined parameters were similar in the two groups. During cooling, blood pressure rose and pulse rate decreased significantly in the men, but not in the women, whereas skin temperature dropped in both groups. However, after cold exposure skin temperature was significantly lower in the women than in the men. A slight, but not significant increase in beta-endorphin, ACTH, cortisol and GH levels was observed after cooling in the men, whereas the women showed significant increments of these hormones. When values of skin temperature were combined with the differential (after minus before cold test) hormonal values, significant negative correlations were found for beta-endorphin, ACTH, cortisol and GH.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of the gamma-aminobutyric acid (GABA) derivative, baclofen, to stimulate growth hormone secretion in heroin addicts.

In order to establish possible alterations in the gamma aminobutyric acid (GABA)ergic control of growth hormone (GH) secretion in heroin addicts, ten patients (age, 25.8 +/- 1.07 yr (mean +/- SE); duration of heroin addiction, range 3-8 yr; weight, 67.3 +/- 0.87 kg body weight), and ten age (29.1 +/- 0.84 yr)- and weight (69.7 +/- 0.87 kg)-matched normal controls were tested with the GABAergic B-receptor agonist baclofen (10 mg p.o. at 09.00 h) (experimental test) or a placebo (control test). Blood samples for GH assay were taken every 15 min for the next 150 min. Normal controls underwent one control and one experimental test. Heroin addicts were submitted to both baclofen and placebo test twice, once around the time of their admission to a recovery community for drug abusers, when they were still assuming heroin, and again after two months of permanence in the community. From the time of their admission to the community, the patients were forbidden to use heroin. For two weeks after admission they were treated with clonidine and acetylsalicilic acid to attenuate withdrawal symptoms. Thereafter, the patients underwent a period of wash-out of pharmacological treatments for at least 6 weeks before being retested. Basal GH levels were similar in normal controls and heroin addicts in all tests and remained unmodified during control tests in all subjects. The administration of baclofen increased four times the serum GH levels within 120 minutes in the normal controls, whereas it did not modify serum GH concentrations in heroin addicts either during the period of drug abuse or after two months of abstinence. These data show that the control of GH secretion mediated by GABAergic B-receptors is impaired in heroin addicts. It is hypothesized that this neuroendocrine alteration might represent a trait marker of heroin addiction, or more likely, that it was a consequence of a long addiction to heroin persisting after two months of abstinence.

Restoration of normal gonadotropin responses to naloxone by chronic bromocriptine treatment in elderly men.

Naloxone is unable to stimulate FSH and LH secretion in elderly men, suggesting a reduced endogenous opioid control of gonadotropin secretion in senescence. In the present study, we examined whether in elderly men a chronic dopaminergic stimulation with bromocriptine (5 mg/day for 7 days) modifies the gonadotropin response to naloxone (4 mg as an i.v. bolus plus 10 mg infused in 2 h). Eleven younger men (group 1, 22-40 years old) participated as controls. Twenty-two elderly men were selected from a larger population and were divided into two groups: subjects with compensated gonadal failure (normal blood testosterone and elevated gonadotropin concentrations; group 2, n = 11; 62-80 years old) and men with normal gonadal function (normal blood testosterone and gonadotropin levels; group 3, n = 11; 61-82 years old). Naloxone induced a striking LH and a slight but significant FSH increase in group 1, but was unable to change serum gonadotropin concentrations in elderly subjects of both groups 2 and 3. When experiments were repeated after bromocriptine treatment, no significant differences in LH and FSH responses to naloxone were observed in the younger subjects. On the other hand, bromocriptine restored significant gonadotropin responses to naloxone in elderly men. In fact, after bromocriptine, naloxone-induced FSH and LH increments in groups 2 and 3 were indistinguishable from those observed in group 1. These data suggest that in men age-related dopaminergic alterations may underlie the defective endogenous opioid control of gonadotropin secretion.