V. Messina

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).

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.

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.

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.

Humoral immunity and lymphocyte subpopulations in patients with dilated cardiomyopathy

The incidence of serum organ and non-organ specific autoantibodies, the peripheral blood lymphocyte blastogenic response to phytohaemagglutinin, concanavalin A and pokeweek mitogen, and the surface markers of peripheral T and B lymphocytes were studied in 15 patients affected by coronary artery disease and in 21 patients with dilated cardiomyopathy. In the latter group there was a significantly impaired blastogenic response to concanavalin A with respect to both the normal control group and patients with coronary artery disease (P less than 0.01). The percentage of peripheral blood lymphocytes with cytotoxic/suppressor activity was also reduced in patients with dilated cardiomyopathy in comparison to normal subjects and patients with coronary artery disease (P less than 0.01 and P less than 0.05, respectively). These data may reflect an in vivo defect in suppressor cell function in patients with dilated cardiomyopathy.

Diurnal Pattern of Plasma and Cerebrospinal-Fluid Vasopressin Levels in Hydrocephalic Patients: Absence of a Circadian Rhythm and of a Correlation between Plasma and Cerebrospinal-Fluid Variations

The arginine vasopressin (AVP) concentrations were determined in plasma and in cerebrospinal fluid (CSF) during a 24-hour period in 7 male patients suffering from hydrocephalus of differing etiologies. Blood and ventricular CSF samples were simultaneously collected every 2 h during the day (08.00-22.00) and every hour during the night (24.00-07.00). In both plasma and CSF, the AVP levels did not show significant time-related circadian variations. No significant correlation was found between the plasma and CSF AVP values during the 24-hour period. The data obtained indicate the absence of the plasma and CSF AVP circadian rhythm in hydrocephalic patients and suggest that in these patients, and possibly in healthy humans, physiological stimuli which are able to induce variations in the plasma AVP concentration during daily life do not alter the CSF AVP content.

Changes in pituitary secretion after administration of branched-chain amino acids to patients with hepatic cirrhosis.

SummaryInfusion of a mixture of branched-chain l-amino acids (BCAA; isoleucine, leucine, and valine) in six male patients suffering from hepatic cirrhosis led to an increase in serum GH, while serum PRL was not affected. In the same patients arginine infusion stimulated GH and PRL release. These findings demonstrate that hypothalamo-pituitary responsiveness to amino acid stimulation is preserved in cirrhosis and that administration of these amino acids has some endocrine effect.

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.

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.

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.