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Biomedical subjects

M Sopena

Publications and source records attributed to M Sopena.

At least 19 recordsLinked to original sources
PubMed1997

Effects of cholinergic blockade on nocturnal thyrotropin and growth hormone (GH) secretion in type I diabetes mellitus: further evidence supporting somatostatin's involvement in GH suppression.

To investigate the influence of cholinergic pathways on somatostatin (SS) tone in type I diabetes mellitus, we studied the effect of the muscarinic receptor antagonist pirenzepine ([PZP] 100 mg orally) on spontaneous nocturnal growth hormone (GH) and thyrotropin (TSH) secretion and on their response to GH-releasing hormone (GHRH) in the morning in a group of nine insulin-dependent diabetic patients with poor diabetic control. When the nocturnal period was divided into two phases (11:00 PM to 2:30 AM and 3:00 AM to 6:00 AM), both GH and TSH mean concentrations during the first phase were higher than those seen in the second half of the night following placebo administration (GH, 13.4 +/- 1.1 v 4.15 +/- 0.9 ng/mL, P < .001; TSH, 1.9 +/- 0.21 v 1.57 +/- 0.1 microU/mL, P < .05). Pretreatment with PZP induced a significant reduction of GH secretion (3.17 +/- 1.1 v 13.4 +/- 1.1 ng/mL, P < .001) and TSH secretion (1.61 +/- 0.21 microU/mL, P < .05) in the first phase of the night, accounting for a 64% and 11% reduction in the GH and TSH nocturnal peak, respectively. PZP reduced the GH response to GHRH in the morning (17.9 +/- 2.7 v 36.7 +/- 6.3 ng/mL, P < .05), but did not induce any change in TSH values at that time. A positive relationship (r = .73, P < .01) was observed between the percent reduction of the GH response to GHRH and that of the nocturnal GH peak following PZP administration. PZP caused a significant reduction in glucose levels during the second phase of the night (6.4 +/- 0.92 v 9.81 +/- 0.85 mmol/L, P < .05). These results demonstrate that administration of PZP reduces GH and TSH secretion, providing further support for the involvement of SS in the inhibition of GH secretion induced by cholinergic antagonists in type I diabetics. The inhibitory effect of PZP on GHRH-induced GH secretion may help to predict nocturnal GH behavior following administration of the drug.

Administration, Oral↗
PubMed1996

Cholinergic modulation of spontaneous hypothalamic-pituitary-adrenal activity and its circadian variation in man.

Controversy still exists regarding the role of cholinergic pathways in the regulation of the hypothalamic-pituitary-adrenal axis in man. We studied the effects of the administration of placebo, pyridostigmine (PD); 120 mg, orally), and the combination of PD and pirenzepine (PZP; 100 mg, orally) on ACTH, cortisol, and GH secretion at 0730 and 2230 h in seven normal males. PD induced a clear decrease in ACTH levels at both times of the day compared to treatment with placebo, producing higher suppression in the nocturnal period (34.4 +/- 5.8% vs. 21.8 +/- 10.7%). The combination PD and PZP prevented the inhibitory action of PD on ACTH secretion in the morning, but not in the evening, when ACTH values showed a decrease similar to that seen after giving PD alone (38.1 +/- 5.6% vs. 34.4 +/- 5.8%, respectively). Cortisol values declined only when the association PD plus PZP was given in the evening. GH levels had a significant increase after PD administration in the morning (4.1 +/- 1.2 ng/mL) and in the evening (10.2 +/- 1.6 ng/mL), confirming that cholinergic stimulation was taking place, whereas the addition of PZP to PD induced a significant attenuation of these responses. It is concluded that cholinergic pathways have a inhibitory role in ACTH secretion in man. M1 muscarinic receptors seem to be involved in the diurnal inhibition of PD, whereas our observations are consistent with the mediation of another type of cholinergic receptors as an explanation for the nocturnal effect of PD on ACTH secretion. PD did not alter the circadian variation in the hypothalamic-pituitary-adrenal axis, whereas the association of PD and PZP increased the differences between diurnal and nocturnal ACTH values, suggesting a modulatory effect of the cholinergic system on the circadian rhythm of ACTH secretion.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Nutrition, energy balance, and obesity].

Energy supply from foods and drinks depends upon carbohydrate, protein, lipid and alcohol content. Cells obtain the energy through a complex and integrated system of physico-chemical processes. The energy value of foods is applied for ATP formation, but also for nutrient utilization and turnover. Net energy from foods is expended for basal metabolism, thermic effect of food and physical activity. Total energy expenditure for human beings is displayed in different lists developed by national and international organisms and institutions. Energy balance and body weight are narrowly interrelated as well as body composition, which depends also of age, sex, exercise and neuroendocrine status. Obesity, is known as an excessive deposition of fat for height, and it is associated with cancer, dislipemias, endocrine abnormalities, diabetes, etc. Recent advances suggest that genetic and neuroendocrine factors are more involved in obesity rather than gluttony or sloth as previously reported.

Body Composition↗