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Biomedical subjects

P Florio

Publications and source records attributed to P Florio.

81 records · Page 5Linked to original sources
PubMedDate not supplied

Effect of acute corticotropin releasing factor on pituitary-adrenocortical responsiveness in elderly women and men.

Aging is related to critical changes of the hypothalamo-pituitary-adrenal function. A decline in serum DHEA levels has been demonstrated in healthy elderly subjects, while ACTH and cortisol concentrations remain at normal values. The purpose of the present study was to investigate the effect of aging on pituitary-adrenal responsiveness to hCRF in subjects of both sexes. A group of 12 physically and mentally healthy elderly subjects and a group of 12 young controls of both sexes have been selected. Blood samples were collected before and after i.v. bolus injection of hCRF; ACTH, cortisol and DHEA levels were then determined by RIA. Basal ACTH and cortisol levels did not result statistically different between controls and elderly subjects, while DHEA showed a clear and significant age-related decrease (p < 0.01). Following the hCRF injection, the responses of ACTH, cortisol and DHEA in aged subjects were higher than in young controls; ACTH (p < 0.03) and cortisol (p < 0.01) were higher in aged women than in men. The present study demonstrated that aging is associated with an increased responsiveness of ACTH, cortisol and DHEA to exogenous hCRF supply. A hyperactivation of the pituitary-adrenal secretory activity may explain the age-related of the same axis. Gender probably has a significant influence on basal and stimulated hormonal secretion. In conclusion, hCRF test may become a useful clinical tool in establishing a neuroendocrine correlation with central disturbances associated to aging.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Activin A, corticotropin-releasing factor and prostaglandin F2 alpha increase immunoreactive oxytocin release from cultured human placental cells.

The aim of the present study was to investigate the presence of the immunoreactive oxytocin in human placental extracts and putative factors regulating the release of immunoreactive oxytocin from cultured human placental cells. Fresh placental tissue was collected from pregnant women at term and dissected of membranes (n = 5). Presence of immunoreactive oxytocin in trophoblast tissue was evaluated by a specific radio-immunoassay after acidic extraction and high-pressure liquid chromatography. In a second set of experiments, primary cultures of placental cells were performed and, 48-72 h after dissociation, the effect of arginine vasopressin, corticotropin-releasing factor, neuropeptide Y, activin A, inhibin A, noradrenaline or prostaglandins on immunoreactive oxytocin level in culture medium was investigated. The presence of immunoreactive oxytocin was shown in the acidic extract of trophoblast at term, and in the culture medium of human placental cells, and it was identical to the native peptide. The addition of corticotropin-releasing factor or arginine vasopressin, but not of neuropeptide Y, increased the release of immunoreactive oxytocin three- to fourfold from placental cells, with a dose-dependent effect (P < 0.01). A significantly increased release of immunoreactive oxytocin was shown in presence of noradrenaline (P < 0.01), which was reversed by prazosin, an antagonist of alpha-adrenergic receptors. Recombinant human activin A (P < 0.01), but not inhibin A, stimulated the release of immunoreactive oxytocin three- to fourfold from placental cells. Prostaglandin F2 alpha was a potent secretagogue of immunoreactive oxytocin, whereas a partial or no effect was observed when prostaglandin E2 or prostaglandin I2 was added. Thus, the present findings showed that human placenta contains immunoreactive oxytocin, and that its release from cultured placental cells is regulated by neurohormones, growth factors or prostaglandins.

Activins↗
PubMedDate not supplied

Cord plasma corticotropin-releasing factor-binding protein (CRF-BP) in term and preterm labour.

Corticotropin-releasing factor-binding protein (CRF-BP) in pregnant women is measurable in maternal and fetal plasma as well as in amniotic fluid. The concentration of CRF-BP in maternal plasma and amniotic fluid changes significantly at the time of parturition. The aim of the present study was to evaluate fetal plasma CRF-BP levels in women delivering at term or with preterm labour. CRF-BP levels were measured the in umbilical cord plasma of women subdivided into two groups: (1) healthy pregnant women throughout the last 5 weeks of pregnancy either (a) out of labour (n = 21) or (b) at delivery after spontaneous labour (n = 64); and (2) patients with preterm labour (a) gone to delivery (n = 12) or (b) responding to tocolysis (n = 10). In the group of healthy women at term, CRF-BP levels were also measured in maternal plasma. CRF-BP was measurable in all specimens of umbilical cord plasma. Mean values +/- SEM at 40 weeks (5.85 +/- 0.65 nmol/l) were significantly lower than those obtained at 37 (6.48 +/- 0.47 nmol/l) or 38 (6.95 +/- 1.16 nmol/l) weeks of pregnancy. Similarly, mean +/- SEM maternal plasma CRF-BP levels in women at term out of labour were lowest at 40 weeks (3.57 +/- 0.22 nmol/l). In these women, mean +/- SEM CRF-BP levels in cord plasma (37 weeks: 6.47 +/- 0.47; 38 weeks: 6.95 +/- 1.16; 40 weeks: 5.85 +/- 0.65 nmol/l) were significantly higher than in maternal plasma at the same gestational age (37 weeks: 4.29 +/- 0.2; 38 weeks: 4.35 +/- 0.205; 40 weeks: 3.57 +/- 0.22 nmol/l). Mean +/- SEM levels of cord blood collected at delivery at term (4.93 +/- 0.14 nmol/l) showed lower CRF-BP levels than in women out of labour (6.18 +/- 0.55 nmol/l). Patients with preterm labour, with delivery within 48 h, showed significantly lower levels of cord plasma CRF-BP (4.21 +/- 0.29 nmol/l) than women at term out of labour (6.18 +/- 0.55 nmol/l) and than those at term with labour (4.93 +/- 0.14 nmol/l). Cord plasma CRF-BP levels decreased in the last 5 weeks of pregnancy, similar to maternal plasma CRF-BP levels, the lowest values resulting in women at labour or with preterm labour, thus suggesting that changes of CRF-BP in cord plasma are associated with the events of parturition.

Adult↗
PubMedDate not supplied

Activin A and inhibin B in extra-embryonic coelomic and amniotic fluids, and maternal serum in early pregnancy.

Activin A and inhibin B levels were measured, using a two-site enzyme immunoassay, in extra-embryonic coelomic fluid, amniotic fluid and maternal serum samples retrieved from 23 healthy pregnant women, at 8 (n=8), 9 (n=8), and 10 (n=7) weeks of gestation. Dimeric activin A and inhibin B were measurable in all samples. Median (+/-SEM) activin A concentrations in coelomic fluid (0.98+/-0.34 ng/ml) were significantly higher than in maternal serum (0.68+/-0.05 ng/ml) and in amniotic fluid (0.09+/-0.04 ng/ml) (P<0.05). Maternal serum activin A levels were significantly higher than amniotic fluid concentrations. Median (+/-SEM) inhibin B concentrations in coelomic fluid (24.32+/-6.02 pg/ml) were significantly higher than in maternal serum (5.94+/-0.97 pg/ml) and in amniotic fluid (6.31+/-1.53 pg/ml) (P<0.05), while no significant difference between maternal serum levels and amniotic fluid concentrations was found. No significant difference in activin A and inhibin B levels in extra-coelomic fluid, amniotic fluid, and maternal serum throughout the 3 weeks of pregnancy was found. The present study showed that coelomic fluid is an important reservoir of activin A and inhibin B, supporting the hypothesis that the extra-embryonic coelom may have a secretory role during the first 11 weeks of gestation.

Activins↗
PubMedDate not supplied

Putative role of placental corticotropin-releasing factor in the mechanisms of human parturition.

Corticotropin-releasing factor is a 41-amino-acid neuropeptide synthesized in the paraventricular nucleus of the hypothalamus and released in response to stress. Its major role is the regulation of the hypothalamus-pituitary-adrenal axis by stimulation of ACTH release from the anterior pituitary gland. In addition, corticotropin-releasing factor modulates behavioral, vascular, and immune responses to stress. Corticotropin-releasing factor was first detected in the extracts of human placentas obtained at full term from spontaneous deliveries. Placental corticotropin-releasing factor content and messenger RNA expression progressively increase during normal pregnancy, and corticotropin-releasing factor levels in maternal plasma have a similar time course. The addition of corticotropin-releasing factor to primary trophoblast cell cultures stimulates ACTH secretion in a dose-dependent manner, and its action is mediated by cyclic adenosine monophosphate as second messenger. In addition, corticotropin-releasing factor is a potent local regulator of myometrial contractility and of membrane prostaglandin release. The effects of corticotropin-releasing factor in these various tissues are mediated by specific receptors. Placental corticotropin-releasing factor is also secreted into the fetal circulation and the stimulation of fetal pituitary ACTH and fetal adrenal gland dehydroepiandrosterone sulfate release in vitro has been shown. Recently, urocortin, a new peptide related to corticotropin-releasing factor, has been found in human placenta. Corticotropin-releasing factor and urocortin share some of their biologic effects, acting on the same receptors. A large-molecular-weight corticotropin-releasing factor-binding protein modulates the activity of both these peptides. Plasma corticotropin-releasing factor levels are low in nonpregnant women and become higher during the second trimester of pregnancy, rising steadily until about 35 weeks, and then increasing more rapidly until term. Vaginal delivery is a condition associated with the highest values of maternal corticotropin-releasing factor levels. Corticotropin-releasing factor is also measurable in fetal plasma (20-fold lower than in maternal circulation) and in amniotic fluid. Increased maternal plasma corticotropin-releasing factor levels characterize some gestational diseases. Women with chronic hypertension and preeclampsia have high corticotropin-releasing factor levels, and intrauterine growth retardation is associated with an activation of the hypothalamus-pituitary-adrenal axis, reflected by increased fetal plasma concentrations of ACTH, cortisol, and corticotropin-releasing factor. The role of corticotropin-releasing factor in preterm labor is uncertain, but midgestational plasma corticotropin-releasing factor levels may be higher in women delivering preterm. In these various pathologic states, maternal plasma corticotropin-releasing factor-binding protein levels undergo opposite changes, decreasing to very low levels. The endocrine-paracrine corticotropin-releasing factor/corticotropin-releasing factor-binding protein pathways may play a major role in the mechanism of human parturition.

Carrier Proteins↗
PubMedDate not supplied

Maternal plasma calcitonin gene-related peptide levels do not change during labor and are not influenced by delivery route.

OBJECTIVE: Calcitonin gene-related peptide (CGRP) circulates in maternal circulation throughout pregnancy, and specific receptors for CGRP (CGRPrs) are expressed by human myometrium. Because CGRP induces a dose-dependent relaxation of human myometrium, we examined a role for CGRP in modulation of myometrial smooth muscle contractility during pregnancy and labor. The aim of the present study was to evaluate the changes of maternal serum CGRP levels during parturition, according to the mode of delivery and in relation to cervical dilatation. METHODS: Circulating CGRP levels were measured in the following groups of healthy women: nonpregnant women, during the follicular phase of the menstrual cycle (n = 19); at term pregnancy (39-40 weeks; n = 24); after elective cesarean delivery (39-40 weeks; n = 20); and at spontaneous vaginal delivery (39-40 weeks; n = 16). In a subgroup of women, blood samples were collected longitudinally throughout labor at various cervical dilatations in the progress of labor (n = 8). RESULTS: Pregnant women at term not in labor had significantly higher CGRP levels than nonpregnant women (P =.021). No significant difference was found between women who delivered vaginally and those who had elective cesarean, and there were no correlations between CGRP plasma levels and cervical dilatation. CONCLUSIONS: Parturition is characterized by no significant changes in maternal serum CGRP levels, and no significant correlation exists between plasma CGRP levels and cervical dilatation during labor.

Adult↗