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Biomedical subjects

T Barreca

Publications and source records attributed to T Barreca.

At least 55 records · Page 3Linked to original sources
PubMed1988

Diurnal changes of plasma and cerebrospinal fluid somatostatin and 24-h growth hormone secretory pattern in man. A study in hydrocephalic patients.

Somatostatin concentration was determined in plasma and in cerebrospinal fluid during a 24-h period in 7 male patients suffering from hydrocephalus of differing aetiologies. Blood and ventricular cerebrospinal fluid samples were taken every 2 h during the day (08.00-22.00 h) and every hour during the night (24.00-07.00 h). Simultaneously, plasma growth hormone levels were also evaluated. Plasma SRIH levels showed significant circadian variations with highest values in the daytime and lowest values during the night. Cerebrospinal fluid SRIH did not show any significant time-related circadian changes. Plasma GH levels showed the well-known circadian pattern in the majority of patients. No significant correlation was found between the plasma GH and plasma or cerebrospinal fluid SRIH values recorded during the 24-h period. Results suggest that peripheral SRIH does not play any major role in the control of the 24-h GH secretory pattern in man.

Adult↗
PubMed1988

Prolactin release induced by physical exercise is independent from peripheral vasoactive intestinal polypeptide secretion.

The plasma concentrations of vasoactive intestinal polypeptide and prolactin were measured before and after an exhaustive and a submaximal exercise test in 7 male marathon runners. A significant increase of vasoactive intestinal polypeptide was recorded after both tests, whereas the prolactin increase was observed only after the exhaustive exercise test. No significant correlation was found between the plasma vasoactive intestinal polypeptide and the plasma prolactin values recorded during the two exercise tests. Data suggest that the exercise-induced prolactin release occurs independently from variations of the vasoactive intestinal polypeptide levels in peripheral circulation.

Adult↗
PubMed1987

Possible role of vasoactive intestinal polypeptide on prolactin release during suckling in lactating women.

The effect of suckling on plasma vasoactive intestinal polypeptide (VIP) values was evaluated in 6 nursing women on the 3rd to 4th day postpartum. Plasma prolactin (PRL) concentrations were also measured. Plasma VIP values (20.6 +/- 3.2 pg/ml in baseline) significantly (p less than 0.05) increased, reaching a maximum (53.5 +/- 10.9 pg/ml) 20 min after the starting of suckling. A possible role of VIP in the suckling-induced PRL release in humans cannot be excluded.

Female↗
PubMed1987

Somatostatin in the elderly: diurnal plasma profile and secretory response to meal stimulation.

Plasma somatostatin levels were determined during a 24-hour period and after a meal test in 7 and 5 elderly subjects (76-90 years), respectively. The data obtained were compared with those recorded in young adult subjects (22-30 years). Increased basal somatostatin values were found in elderly subjects (20.0 +/- 1.5 pg/ml) when compared to young adults (14.1 +/- 0.6 pg/ml; p less than 0.01). Also, the mean 24-hour somatostatin levels were higher in the elderly (21.3 +/- 0.8 pg/ml) than in young adults (16.7 +/- 0.5 pg/ml; p less than 0.01), and minor diurnal variations were found in the former group. The response to the meal test was less evident in the elderly than in the control group. The data obtained indicate an increased basal somatostatin production associated with a diminished variability throughout the 24-hour period and in relation to meals.

Adult↗
PubMed1987

Twenty-four-hour beta-endorphin secretory pattern in the elderly.

A chronobiological study was carried out in seven elderly male subjects (78-84 years) to evaluate the 24-h beta-endorphin secretory pattern. Seven young adult males (28-37 years) made up the control group. Blood samples were drawn every four hours from 08.00 to 20.00 h and every two hours from 24.00 to 06.00 h. ACTH and cortisol levels were also determined in the same plasma samples. Mean 24-h beta-endorphin values in the elderly (32.6 +/- 1.1 ng/l) and in the young adult male subjects (29.5 +/- 1.4 ng/l) did not differ statistically, but the circadian rhythm was absent in the elderly subjects. In the elderly, plasma ACTH and cortisol concentrations showed a circadian rhythm similar to that observed in the adult subjects. However, in the elderly patients, in contrast to that in the adult subjects, the multilinear regression analysis did not show any statistically significant correlation between the beta-endorphin, ACTH and cortisol 24-h plasma concentrations.

Adrenocorticotropic Hormone↗
PubMed1987

Effects of dynorphin on the PHA-induced lymphocyte proliferation in vitro.

The effect of the opioid peptide dynorphin (DYN) on PHA-induced lymphocyte proliferation has been evaluated in the present study. A significant increase in PHA-induced lymphocyte activation was observed when DYN was added to cultures 48 hr after the mitogenic stimulation. This effect occurred at suboptimal (3.12 and 6.25 micrograms/ml) PHA concentrations and at DYN doses ranging from 10(-9) to 10(-12) M. Conversely, DYN did not affect the lymphocyte blastogenic process either when added before, or simultaneously or after intense PHA (12.5 micrograms/ml) stimulation. Naloxone preincubation did not modify the above described effects. Results suggest that DYN might play a role in neuroendocrine regulation of the lymphocyte blastogenic process.

Adult↗
PubMed1986

Diurnal beta-endorphin changes in human cerebrospinal fluid.

Plasma and cerebrospinal fluid (CSF) beta-endorphin levels were determined by a RIA method in seven hydrocephalic male patients. The samples were simultaneously collected every two hours from 8 AM to 12 midnight and every hour from 1 AM to 7 AM. In both plasma and CSF beta-endorphin levels showed significant time-related variations during the 24 hour period. These results suggest the existence of diurnal CSF beta-endorphin variations analogous to those observed in plasma.

Adult↗
PubMed1986

Inhibition of prolactin and aldosterone secretion by the dopamine derivative ibopamine.

In 7 patients with congestive heart failure acute oral administration of ibopamine, a new dopamine derivative, induced a significant decrease in serum prolactin and aldosterone without affecting serum growth hormone or cortisol. The Metoclopramide-induced secretion of prolactin and aldosterone was blunted in 6 patients pretreated with 200 mg ibopamine. The data are consistent with a dopaminergic effect of ibopamine due to a peripheral action, probably on D-2 receptors.

Adult↗
PubMed1986

Suppression of testicular androgenesis by D-tryptophan-6-luteinizing hormone-releasing hormone does not affect TSH secretion in male subjects.

Basal and TRH-stimulated TSH secretion was evaluated in six patients suffering from prostatic cancer, before and after antiandrogenic treatment performed using a long-acting LHRH analogue, D-Trp-6-LHRH. Although serum testosterone values dropped to minimal levels after treatment, TSH secretion remained unchanged. Observed results suggest that pharmacological castration does not affect the regulatory mechanisms involved in the control of TSH secretion.

Aged↗
PubMed1986

Blunted response of serum aldosterone to metoclopramide in the male elderly.

Serum aldosterone values were determined in 6 elderly (70-82 years) and in 6 adult (31-43 years) male subjects after the intravenous administration of 10 mg of metoclopramide. A significant difference in the metoclopramide-induced serum aldosterone rise was found between the two groups, it being blunted in the older subjects (serum aldosterone peak values: 15.8 +/- 3.6 ng/dl and 38.7 +/- 4.9 ng/dl in elderly and in adult subjects, respectively). The existence of an impaired aldosterone secretion in response to dopaminergic blockade in the elderly is postulated.

Adult↗
PubMed1986

Treatment of prostatic cancer with a depot form of a luteinizing hormone-releasing hormone analogue.

Chronic administration of a depot form of D-Trp6 luteinizing hormone-releasing hormone (LH-RH), an LH-RH analogue (3 mg i.m. every 28 days for a mean period of 9.1 months), to 14 patients with locally extended or metastatic cancer of the prostate provided a good degree of disease control. After a slight and transient increase in gonadotropin secretion, the peptide induced a sharp and long-lasting inhibition of both gonadotropin and testosterone secretion, contemporaneously with clinical improvement and without any important side effects. These results are comparable to those recorded by others after daily administration of LH-RH analogues.

Acid Phosphatase↗
PubMed1985

Variations of prolactin content in human cerebrospinal fluid after metoclopramide and morphine.

Serum and cerebrospinal fluid (CSF) prolactin (PRL) concentrations were determined in fourteen patients of both sexes suffering from hydrocephalus, in basal conditions and after i.m. administration of 10 mg metoclopramide or 10 mg morphine. A significant increase in both serum and CSF hormone values was found after administration of both drugs. Serum and CSF PRL values after metoclopramide administration increased earlier and to a greater extent than after morphine. Furthermore, the metoclopramide induced CSF PRL increase immediately followed the serum peak, whereas after morphine administration an evident delay in the CSF hormone peak with respect to the serum increase was found. These data suggest that PRL entry in the CSF compartment is subject to a controlling mechanism which acts at the blood/brain barrier.

Adult↗
PubMed1985

Influence of beta-endorphin on phytohemagglutinin-induced lymphocyte proliferation and on the expression of mononuclear cell surface antigens in vitro.

Recent evidence suggests that opiates can modulate the immune responses. In particular it has been shown that beta-endorphin and morphine are able to depress some T lymphocyte functions in humans. In the present study, experiments were designed to evaluate the effect of beta-endorphin phytohemagglutinin-induced lymphocyte proliferation and determine the mechanism of this action. The ability of naloxone to block the effect of beta-endorphin was also investigated, and the influence of beta-endorphin on the expression of mononuclear cell surface antigens using the OKT3, OKT4, OKT8, anti-HLA-DR and anti-beta 2-microglobulin monoclonal antibodies was evaluated. Phytohemagglutinin-induced lymphocyte proliferation was significantly inhibited by beta-endorphin. This effect occurred when beta-endorphin was added to cells at the beginning of the culture period (30 min before, simultaneously or 30 min after phytohemagglutinin), but not when added after 48 h of incubation. The preincubation of cells with BEP for 1 h, 4 h or 24 h did not affect lymphocyte activation by phytohemagglutinin. A ten-fold excess of naloxone, added to cultures 30 min prior to beta-endorphin, did not block the inhibitory effect. Incubation with beta-endorphin had different effects on each surface antigen tested. The OKT8+ and beta 2-microglobulin+ cells did not show significant variations. The OKT4+ cells significantly decreased, after 4 h of incubation with beta-endorphin, both in mononuclear cell and in purified T lymphocyte cultures and, after 24 h, in mononuclear cell cultures only. The OKT3+ cells decreased, in mononuclear cell cultures only, after 24 h beta-endorphin incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1985

Comparison of pituitary responses to physical exercise in athletes and sedentary subjects.

Serum growth hormone (GH), prolactin (PRL), cortisol, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH) levels were evaluated before and after a bicycle ergometer exercise test in 8 male competitive volleyball players and in 8 sedentary healthy males of the same age. Increased serum GH and cortisol values after exercise in both groups were found, whereas an exercise-induced PRL release was observed in athletes only. Serum levels of LH, FSH and TSH were unaffected by the test in all subjects. A possible role of training in conditioning the hypothalamopituitary exercise-induced secretion is suggested.

Adult↗
PubMed1985

Stimulation of growth hormone release by thyrotropin-releasing hormone in elderly subjects.

The effect of thyrotropin-releasing hormone (TRH) on the release of growth hormone (GH) was investigated in 16 elderly male subjects aged 74-88 years. Intravenous injection of 200 micrograms TRH induced a clear-cut GH rise (greater than or equal to 10 ng/ml) in 7 of 16 subjects. TRH administration did not raise plasma GH in 10 adult subjects aged 36-58 years. The results suggest disorders in neurobiochemical mechanisms regulating hypothalamopituitary function in elderly men.

Adult↗
PubMed1985

24-hour thyroid-stimulating hormone secretory pattern in elderly men.

A chronobiological study was carried out in 10 elderly male subjects (78-83 years) to evaluate the 24-hour thyroid-stimulating hormone (TSH) secretory pattern. 10 young adult males (26-35 years) made up the control group. Hourly blood samples were drawn from each subject for a 24-hour period. TSH levels in elderly subjects showed blunted circadian fluctuations compared to those seen in young adult subjects. Mean 24-hour TSH values in elderly (3.1 +/- 0.3 microU/ml) and young adult subjects (3.5 +/- 0.1 microU/ml) did not differ statistically, but nighttime TSH values observed in elderly subjects (3.2 +/- 0.3 microU/ml) were lower (p less than 0.05) than those recorded in young adults (4.1 +/- 0.1 microU/ml).

Adult↗
PubMed1984

Serum concentrations of PRL, GH, LH, FSH, TSH and cortisol after single administration to man of a new synthetic narcotic analgesic butorphanol.

The i.m. administration to 6 healthy adult male volunteers of 2 mg butorphanol, a potent synthetic opiate analgesic, resulted in a significant rise in serum PRL level, without affecting GH, LH, FSH, TSH or cortisol secretion. These effects indicate that in man butorphanol exerts an opiate agonist rather than an opiate antagonist effect at the hypothalamic and/or pituitary level.

Adult↗