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Biomedical subjects

R Valentino

Publications and source records attributed to R Valentino.

At least 55 records · Page 3Linked to original sources
PubMed1994

Interleukin-1 beta plasma secretion during diurnal spontaneous and induced sleeping in healthy volunteers.

We previously reported nocturnal plasma IL-1 beta (beta) increases during sleep in absence of stress-induced activation of hypothalamic-pituitary-adrenal (HPA) axis. In this paper we evaluate the presence of plasma IL-1 beta secretion in nine healthy volunteers (mean age 31.2 +/- 4.2) during post-prandial naps, after the administration of zolpidem, a benzodiazepine receptorial agonist. Although a significant increase in IL-1 beta plasma levels during spontaneous sleep was present in only four subjects when compared to those obtained during wake and induced-sleep, spontaneous sleep IL-1 beta mean plasma levels appeared slightly higher than both wake and induced-sleep values. Moreover, a negative correlation was present between IL-1 beta and cortisol (F) values obtained during the early afternoon (r = 7; p < 0.05). Our findings are consistent with a possible association of IL-1 beta secretion to physiologic sleep also during daytime spontaneous naps, with the presence of F influence on this phenomenon, and with the lack of IL-1 beta association to daytime naps after sleep-inducer pharmacological agents.

Administration, Oral↗
PubMed1993

Hormonal pattern in women affected by rheumatoid arthritis.

Gonadal sex hormones may account for the sexual dimorphism in the immune response and for the greater incidence of autoimmune disease in females. We have previously reported the presence of progesterone (P) deficiency in female patients with thyroid and ovarian autoimmune disease. In this context, the hormonal profile in 9 women with rheumatoid arthritis (RA) and in 9 age-matched ealthy women, were evaluated to verify the presence of a steroid hormone secretion impairment in a systemic autoimmune disease, further supporting our hypothesis of P deficiency involvement. P and androgen plasma levels, in the luteal phase, were significantly lower (p < 0.05 and 0.005, respectively) in RA patients than in the control group, with a consequent decrease of the free androgen index. Moreover, despite normal cortisol values, corticosterone (B) plasma levels were significantly higher in the RA patients (p < 0.01 and 0.05 in follicular and luteal phase, respectively). Therefore, our present data confirm the androgen deficiency in patients with a systemic autoimmune disease, such as RA and support the immunomodulator effect of P. Finally, the higher B plasma levels in RA patients may suggest the presence of a slight impairment of the immune hypothalamic-pituitary-adrenal axis (HPAA), supporting its role in certain phases of RA pathogenesis. In conclusion, in addition to androgens, the immunomodulator role of P should also be taken into account in the pathogenesis of the systemic autoimmune disease.

Adult↗
PubMed1993

Derangement of the hypothalamic GnRH pulse generator in women with epilepsy.

An increased frequency of reproductive endocrine diseases has been described in women with epilepsy and a subclinical reproductive dysfunction has been suggested in normally menstruating epileptic women. We assessed the reproductive endocrine function in 11 normally menstruating, drug-free epileptic women, evaluating the basal hormonal profile and LH pulsatile secretion during continuous EEG monitoring. A significant LH hyperpulsatility was observed in epileptic women compared with controls; moreover, a significant increase of gonadotropin basal secretions was observed when inter-ictal paroxysmal activity increased. The derangement of the hypothalamic GnRH pulse generator may represent a subclinical condition associated with epilepsy, not necessarily affecting the regularity of menstrual function. However, it is possible that the alteration of LH pulsatile pattern might eventually cause reproductive endocrine diseases. Paroxysmal activity seems to be an important additional factor in the derangement of gonadotropin secretion.

Adolescent↗
PubMed1993

11-beta-hydroxysteroid dehydrogenase activity and gene expression in the hypertensive Bianchi-Milan rat.

OBJECTIVE: 11 beta-Hydroxysteroid dehydrogenase (11 beta-HSD), by converting the active steroids cortisol and corticosterone to their inactive metabolites, regulates steroid exposure to the mineralocorticoid and glucocorticoid receptors. We explored the hypothesis that a defect in 11 beta-HSD could result in overstimulation of either the mineralocorticoid or glucocorticoid receptors with subsequent hypertension in an established animal model of hypertension, the Bianchi-Milan hypertensive (BMH) rat. DESIGN AND METHODS: Groups of BMH rats with established hypertension (42-46 days old) and prehypertensive rats (22 days old) were compared with age-matched normotensive control rats. Kidney and liver 11 beta-HSD and glucocorticoid receptor messenger RNA (mRNA) levels were assessed by Northern and dot-blot analyses, and 11 beta-HSD activity as percentage conversion of [3H]-corticosterone to [3H]11-dehydrocorticosterone by tissue homogenate. RESULTS: Hepatic 11 beta-HSD activity and gene expression were significantly reduced in the hypertensive BMH rat compared with its normotensive genetic control. 11 beta-HSD activity was also reduced in the prehypertensive BMH rat (aged 25 days) from hypertensive parents, excluding hypertension per se as the cause of the abnormality. Plasma corticosterone was higher in the hypertensive rats. There was no difference in renal 11 beta-HSD activity or gene expression between hypertensive and normotensive BMH rats, or in glucocorticoid receptor gene expression in the liver or kidney. CONCLUSIONS: Normal levels of renal 11 beta-HSD mRNA and activity are found in the BMH rat. However, the hypertensive BMH rat does demonstrate impaired hepatic 11 beta-HSD activity which occurs at a pretranslational level, although it is not clear how this relates to the pathogenesis of hypertension in this model.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1992

Cortical norepinephrine release elicited in situ by N-methyl-D-aspartate (NMDA) receptor stimulation: a microdialysis study.

Norepinephrine (NE) release measured by microdialysis from probes positioned in the prefrontal cortex of anesthetized rats was increased when N-methyl-D-aspartate (NMDA) was contained in the microdialysis medium. NE release increased by a factor of 3.6 compared to prior baseline levels when 1 mM NMDA was applied for 30 min. This increase was largely reversible, and when a second stimulation was applied using aconitine (0.3 mM, 30 min), which acts on voltage-sensitive sodium channels, a second evoked release of NE was observed, of a similar magnitude as that evoked by NMDA. Dizocilpine (300 nM), which blocks cation channels associated with NMDA receptors, prevented the NMDA-elicited NE increase but not the aconitine-elicited increase.

Aconitine↗
PubMed1991

Abnormal pattern of luteinizing hormone pulsatility in women with epilepsy.

Dysfunction of the hypothalamic-pituitary-ovarian axis in epileptic females has been suggested in the latest years. To further elucidate this issue, we assessed reproductive endocrine function in 10 normally cycling, drug-free epileptic women and in 5 normal controls, evaluating the basal hormonal profile and luteinizing hormone (LH) pulsatility in the midfollicular phase. Luteinizing hormone pulse frequency was significantly higher in epileptic women with a consequent reduction of the LH interpulse interval. We suggest that epilepsy may interfere with the functional activity of the gonadotropin-releasing hormone pulse generator. The pathogenetic mechanisms for this phenomenon may be the spreading of paroxysmal activity within the hypothalamic areas or, alternatively, a neurotransmitter dysfunction giving rise both to the seizure disorder and to the abnormal LH pulsatile pattern.

Adult↗
PubMed1990

A pilot study for neonatal screening of congenital adrenal hyperplasia due to 21-hydroxylase and 11-beta-hydroxylase deficiency in Campania region.

A neonatal screening for both 21-hydroxylase and 11-beta-hydroxylase deficiencies, responsible for congenital adrenal hyperplasia (CAH), has been conducted in Campania Region, Southern Italy. In 4380 neonates, aged 2-10 days, capillary blood from a heel prick was collected on microfilter paper, and 17-alpha-hydroxyprogesterone (17OHP) measured by radioimmunoassay (RIA) using a highly specific antibody (Ab A). In addition, in 295 of these samples, both 17OHP and 11-deoxycortisol (S) were measured using an anti-deoxycortisol antibody (Ab B) cross-reacting with 17OHP 100%. All results were compared with plasma 17OHP and S levels in 21 patients with diagnosed 21-hydroxylase deficiency and in 5 healthy volunteers on metyrapone test used for blocking the 11-beta-hydroxylase activity. CAH due to 21-hydroxylase deficiency was diagnosed in a female newborn. The assay, based on the antibody reacting with both 17OHP and S, is particularly suitable for wide-scale screening programs enabling the simultaneous detection of two congenital enzyme defects.

Adolescent↗
PubMed1989

Licorice inhibits corticosteroid 11 beta-dehydrogenase of rat kidney and liver: in vivo and in vitro studies.

In humans, glycyrrhetinic acid (GE), the active pharmacological ingredient of licorice, produces symptoms resembling those caused by excess mineralocorticoid secretion. We are proposing that 11 beta-dehydrogenase inhibition, and not intrinsic mineralocorticoid activity, is the primary mechanism of licorice induced pseudoaldosteronism. Glycyrrhizic acid (glycyrrhetinic acid glucuronide), when given orally to rats, partially inhibited renal 11 beta-dehydrogenase. In rats treated with dexamethasone before glycyrrhizic acid administration there was similar enzyme inhibition, suggesting that antimineralocorticoid effects of dexamethasone in licorice excess states are not mediated through a direct effect on 11 beta-dehydrogenase activity. Dispersed renal proximal tubular preparations, kidney homogenates, and microsomes readily converted corticosterone to 11-dehydrocorticosterone. GE and its synthetic analog carbenoxolone inhibited the conversion in these systems in a dose-dependent manner. Corticosteroid 11-oxoreductase, which was present in kidney homogenates at a level 10-20% that of 11 beta-dehydrogenase was not inhibited by any of the agents. With homogenate and microsomes, the Ki of GE was about 10(-9)-10(-8) M; with intact tubules, the Ki of GE was about 10(-5)-10(-6) M. It is suggested that a permeability barrier slows the entry of GE into the tubule cells. We conclude that the effects of licorice on corticosteroid metabolism in the kidney are based on its inhibition of 11 beta-dehydrogenase. Our data, supplemented by published evidence, is inconsistent with the conclusion that interaction with mineralocorticoid receptors accounts for the pharmacological effects of GE.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1987

Mineralocorticoid activity of liquorice: 11-beta-hydroxysteroid dehydrogenase deficiency comes of age.

The sodium retention associated with liquorice ingestion has been thought to be due to a direct mineralocorticoid effect, despite the fact that it does not seem to occur in patients or animals with severe adrenal insufficiency. This study in seven normal subjects given liquorice showed that sodium retention is associated with a significant change in cortisol metabolism indicating inhibition of 11-beta-hydroxysteroid dehydrogenase (11 beta-OHSD). Congenital deficiency of this enzyme produces a syndrome of apparent mineralocorticoid excess. It is suggested that in both conditions there is a defect in the renal conversion of cortisol to cortisone by 11 beta-OHSD which results in high intrarenal cortisol levels, acting on type 1 mineralocorticoid receptors to cause sodium retention.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1986

Low-renin primary hypertension in a young patient treated with dexamethasone.

We have studied a young untreated patient with low-renin hypertension. All the clinical tests were in normal range, except plasma renin activity, which was low. Also all traditional tests evaluating the adrenal function were normal. A test of supraphysiological ACTH stimulation revealed a partial enzymatic defect of adrenal 11-hydroxylase. The patient has been treated with dexamethasone (0.75 mg once daily), during 4 weeks. At the end of the treatment blood pressure reached normal values. The traditional adrenal function tests are not sufficient to exclude enzymatic abnormalities and their possible involvement in the pathogenesis of hypertension.

Adrenocorticotropic Hormone↗
PubMed1982

[Evaluation of aldosterone, corticosterone, glucose and triglyceride blood levels in pregnant rats fed a high protein diet].

Pregnant rats, Wistar strain, fed a rich protein diet (row casein 40%, milk-albumin 20%) from the beginning or from the eighth day of pregnancy. The comparison with control rats, receiving an usual diet, showed that the high protein intake produced an expressive increase of haematic glucose and triglycerides and a very significant diminution of serum aldosterone and corticosterone, particularly when the experimental diet was begun from the first day of pregnancy. The Authors suppose a damage of adrenal cortex and intend to clarify in a next work this possibility by an histologic study.

Aldosterone↗
PubMedDate not supplied

Functional hyperandrogenism detected by corticotropin and GnRH-analogue stimulation tests in women affected by apparently idiopathic hirsutism.

The etiologic diagnosis of hirsutism is often difficult. Previous studies have reported normal basal androgen and SHBG concentrations in 33-50% of hirsute women, suggesting the presence of an "idiopathic" form of hirsutism as the most frequent cause of this problem. The recent use of GnRH-analogues together with the corticotropin stimulation test allows better understanding of whether the cause of hirsutism is androgen excess and, if so, whether the origin of the latter is ovarian, adrenal or both. The present study evaluated adrenal and ovarian function in 48 young hirsute women as well as in 78 normal women matched for body mass index and age, who acted as control group. To determine ovarian function, a single 100-microg dose of GnRH analogue triptorelin was injected s.c.; thereafter, gonadotropins, 17-hydroxyprogesterone (17-OHP), delta4-androstenedione (delta4), total testosterone (T) and estradiol were determined. To better understand the adrenal function, 250 microg of 1,24 ACTH were administrated as i.v. infusion for 5 h, and plasma cortisol (F), 17-OHP, A4, DHEAS, T, 11-desossicortisol were measured. The combined use of these two stimulation tests was able to detect mild to moderate abnormalities in the steroidogenesis of ovaries alone (23%), adrenals alone (16.6%), or both (35.4%) in most hirsute women (75%) with otherwise normal baseline androgen concentrations. In particular, patients showed significantly increased responses of 17-OHP, delta4, total T, 11-desossicortisol, and F to 1,24-ACTH administration. Moreover, they also had significantly higher 17-OHP and T responses to triptorelin. In conclusion, milder forms of functional ovarian and/or adrenal hyperandrogenism, similar to those found in clearly hyperandrogenic women, were observed and could be an underlying mechanism of idiopathic hirsutism.

Adrenal Glands↗
PubMedDate not supplied

Partial deficiency of adrenal 11-hydroxylase. A possible cause of primary hypertension.

Results of supraphysiological adrenocorticotropic hormone (ACTH) stimulation of biosynthetic pathways of adrenal zona fasciculata indicate that a deficiency of 11-hydroxylase exists in patients with essential hypertension. The deficiency is suggested by the much greater stimulus of synthesis of deoxycorticosterone (DOC) and deoxycortisol in hypertensive subjects than in controls (p less than 0.001). No significant difference in the synthesis of cortisol, corticosterone, progesterone, 17-hydroxyprogesterone (17-OHP), and delta-4-androstenedione (D4) was observed between the two groups. The ratios for synthesis of DOC and corticosterone and for deoxycortisol and cortisol found in hypertensive patients were significantly higher than those found in controls (p less than 0.001); no significant difference was observed in the synthesis of 17-OHP and progesterone. The synthesis of DOC and deoxycortisol was not significantly correlated with either blood pressure or plasma renin activity. Plasma renin activity was significantly lower in hypertensive subjects than in normotensive subjects (p less than 0.0001), while no difference was found in aldosterone secretion between the two groups. The 11-hydroxylase deficiency in the adrenal zona fasciculata may be one of the genetic factors causing hypertension together with environmental factors (particularly salt intake and work-related stress). The investigation performed in our study may be useful for the evaluation of adrenal zona fasciculata enzymatic activities during the study of hypertensive patients.

17-Hydroxycorticosteroids↗