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F Alba

Publications and source records attributed to F Alba.

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

[Effect of chronic blockade of the opiodergic receptor on insulin resistance in a hyperandrogenic woman].

We report a woman with insulin resistance associated with hyperandrogenism and acanthosis nigricans (HAIR-AN syndrome) treated during 30 days with the prolonged action opioid antagonist Naltrexone. During its administration, decreases in basal blood glucose and serum insulin, insulin and glucose response to a glucose load and plasma testosterone were observed. These findings suggest that opioid activity could play a critical role in the physiopathology of hyperinsulinemia in hyperandrogenic women.

Acanthosis Nigricans↗
PubMed1993

Regional distribution of soluble and membrane-bound aminopeptidase activities in rat brain.

Soluble and membrane-bound aminopeptidase activities in 11 regions of the rat brain were assayed using L-Leucine-2-naphthylamide as a substrate. In addition, two metabolic enzymatic activities were compared: lactate dehydrogenase and aspartate aminotransferase. All enzymatic activities showed significant regional differences when the data were analyzed statistically. Soluble aminopeptidase and aspartate aminotransferase activities were significantly lower in cortical than in subcortical areas. Membrane-bound aminopeptidase activity levels were higher in cortical areas. Lactate dehydrogenase activities did not differ between cortical areas and the rest of the zones studied. However, although no wide regional differences were found for the other enzymatic activities, membrane-bound aminopeptidase varied markedly across brain regions: a fivefold difference was observed between zones such as parietotemporal cortex and medulla. The differential distribution of this enzymatic activity is consistent with the hypothesis that it could be responsible for the enzymatic inactivation of some neuroactive peptides.

Aminopeptidases↗
PubMed1992

[Regional distribution of brain aminopeptidases in the rat].

Soluble and membrane-bound aminopeptidase activities in eleven regions of the rat brain were assayed using L-leucine-2-naphthylamide as a substrate. In addition, two metabolic enzymatic activities were compared: lactate dehydrogenase and aspartate aminotransferase. All enzymatic activities showed significant regional differences when the data were analyzed statistically. Soluble aminopeptidase and aspartate aminotransferase activities were significantly lower in cortical than in subcortical areas. Membrane-bound aminopeptidase activity levels were higher in cortical areas. Lactate dehydrogenase activities did no differ between cortical areas and the rest of the zones studied. However, while no wide regional differences were found for the other enzymatic activities, membrane-bound aminopeptidase varied markedly across brain regions: a 5-fold difference was observed between zones. The differential distribution of this enzymatic activity is consistent with the hypothesis that it is responsible for the enzymatic inactivation of some neuroactive peptides.

Aminopeptidases↗
PubMed1992

[Ovulation induction by the chronic administration of naltrexone in a patient with secondary hypothalamic amenorrhea].

An ovulatory cycle was induced by oral administration of a specific opiate antagonist: naltrexone, at a dose of 50 mg/day for 26 days in a woman suffering from secondary hypothalamic amenorrhea. The follicular growth was monitored by ultrasound and serial blood measurement of LH, FSH, E2 and progesterone. The hormonal and ultrasound profiles showed an ovulatory cycle with a single dominant follicle. After discontinuation of the treatment, the patient became amenorrheic again. The gonadotropin as well as estradiol plasma levels declined, to that observed before treatment. Naltrexone may be a useful agent for induction of ovulation in women suffering from hypothalamic amenorrhea.

Adolescent↗
PubMed1991

[Effect of microsurgical resection of the ovary on fertility in patients with polycystic ovary resistant to clomiphene citrate].

Thirteen patients with clomiphene citrate resistant polycystic ovary syndrome (PCO-CR) were documented by clinical and endocrine profile. Exogenous gonadotropins (HMG, hFSH, hCG), or gonadotrophin releasing hormone agonist (GnRHa) plus gonadotropins represent a new approach to induce ovulation in these (PCO-CR) patients. 92% of these patients ovulated with exogenous gonadotropin, nevertheless the pregnancy rate was only 53%. Five out seven PCO-RC patients did not achieve pregnancy with exogenous gonadotrophins, but they did after ovarian wedge resection. It is interesting to note that four of these patients achieved their second and third pregnancy without any therapy. The authors conclude that the ovarian wedge resection may had to improve in the quality of ovulation in this very selective group of infertile patients.

Adult↗
PubMed1990

Pulsatile luteinizing hormone secretion in women with polycystic ovary syndrome under clomiphene citrate. Differences between responders and nonresponders.

Although administration of Clomiphene Citrate (CC) is an effective therapy for ovulation induction in PCO patients, 15 to 20% of PCO patients do not ovulate following CC treatment. The aim of this study was to compare the endocrine dynamics (LH pulsatile pattern, FSH and steroid hormone changes) in 6 patients who ovulated (PCOS) and 6 PCO patients who did not ovulate in response to CC (PCOR). Blood was collected at 15 min intervals for 4 hr on day 9 of the first menstrual cycle (control cycle) and on day 9 of the following (treatment) cycle. In this cycle all women received 100 mg CC/day from day 5 to day 9. LH was determined in all samples whereas FSH and estradiol were measured every 60 min. No significant differences were observed regarding the age, body mass index, degree of hirsutism, ovarian volumes and basal levels of reproductive hormones between both groups of PCO women. During the control cycle, the LH pulse amplitude and transverse LH mean concentrations in PCOR patients were higher than in PCOR patients whereas the LH pulse frequency was similar in both groups. No difference was found in FSH and estradiol values between both groups. Compared to the control cycle, PCOR patients showed no change in the pulse amplitudes and no difference in LH, FSH and estradiol values following CC treatment. In contrast, during the CC therapy in PCOS patients an increase in the LH amplitude (p less than 0.05), the transverse mean LH concentration (p less than 0.05), FSH and estradiol was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Regulation of steroid hormone synthesis by human corpora lutea: failure of follicle-stimulating hormone to support steroidogenesis in vivo and in vitro.

The authors studied the role of follicle-stimulating hormone (FSH) in luteal steroidogenesis by replacing gonadotropin-releasing hormone (GnRH) infusion with pure FSH 48 hours after ovulation in two hypogonadotropic patients. Plasma progesterone (P) and estradiol (E2) decreased after FSH administration. Human luteal cells were cultured for 48 hours in the presence and absence of FSH, human chorionic gonadotropin (hCG), testosterone (T), or dibutyryl cyclic adenosine monophosphate (Bu2cAMP). In the presence of T, E2 synthesis increased significantly, indicating an active aromatase system in these cells. Human chorionic gonadotropin as well as Bu2cAMP significantly increased E2, T, and P synthesis. Follicle-stimulating hormone did not stimulate luteal E2, T, or P synthesis. The authors conclude that FSH does not sustain luteal steroidogenesis. Moreover, the in vitro findings reveal that hCG modulation of luteal E2 synthesis is mediated principally by an increase in androgen precursors. These in vivo and in vitro results confirm a crucial role for luteinizing hormone (LH) in the maintenance of luteal steroidogenesis.

Adult↗
PubMed1988

Aminopeptidase activity is asymmetrically distributed in selected zones of rat brain.

Levels of soluble aminopeptidase (AP), measured as arylamidase activity using L-Leucine-2-Naphthylamide (Leu-2-NA) as substrate, were determined in the soluble fraction of eleven zones of rat brain. Results showed that AP activity is asymmetrically distributed in frontal cortex and hypothalamus with both left sides having significantly higher levels of AP activity, respectively, than the right sides. Simultaneously, the activities of lactate dehydrogenase (LDH) and glutamate-oxalacetate aminotransferase (GOT) were measured in the same cerebral regions; no significant difference was recorded in these activities between either side of the rat brain in any of the zones studied. Provided that aminopeptidases are involved in the degradation of some endogenously released neuropeptides, the results suggest a new mode of expression of cerebral lateralization.

Aminopeptidases↗
PubMed1986

Asymmetrical distribution of aminopeptidase activity in the cortex of rat brain.

The levels of soluble aminopeptidase (AP) activity were measured in the right and left frontal (FC), parietotemporal (PTC) and occipital (OC) cortex of male albino rat brains. The results showed more AP activity in the left cortex than in the right. Analyzing these results further, we found that the differences are significant for frontal cortex but not for parietotemporal nor occipital cortex. However, 76% of the rats were left-predominant for AP activity in the 3 cortical areas studied.

Aminopeptidases↗
PubMed1983

Monoamines and self-stimulation of the medial prefrontal cortex in the rat.

The participation of noradrenaline (NE) and serotonine (5-HT) in self-stimulation (SS) of the medial prefrontal cortex (MPC) in the rat has been studied. Three groups of rats with bilateral electrodes implanted into the MPC were used in these experiments. In one of the groups, electrodes were also implanted into the locus coeruleus. In the first group, the rats received systemic injections of the following drugs: clonidine (alpha-agonist), phenoxybenzamine (alpha-antagonist), isoproterenol (beta-agonist) and propranolol (beta-antagonist). In the second group, p-chlorophenylalanine (a 5-HT synthesis inhibitor) was administered intragastrically and SS measured during the following 16 days. In these two groups of rats and previous to every SS session, spontaneous motor activity (SM) was measured as control for non specific effects of the drugs. In a third group of rats, lesions of the locus coeruleus were performed unilaterally and SS measured in both prefrontal cortex during the following 16 days post-lesion. SS contralateral to the lesioned side served as control for non-specific effects of the lesions. After all these treatments, SS of the MPC was not specifically affected. Our results suggest the non participation of NE and 5-HT terminals in the neural substrates underlying SS of the MPC.

Adrenergic alpha-Antagonists↗
PubMed1982

[Not Available].

Explore the source record for details and available documents.

Demography↗
PubMed1982

Calcium and renin release: inhibition of low sodium-induced renin secretion by high calcium concentration in rat kidney perfusion.

The effects of changes in calcium on renin secretion have been studied in the isolated perfused rat kidney. Perfusion with free calcium buffer significantly decreases renin secretion as compared with control experiments (Ca++: 2.5 mM/l). Other calcium concentrations (1.25 mM/l) and 5 mM/l) do not affect basal renin secretion. When the renin release is previously increased by low sodium concentration (Na+: 110 mM/l) however, perfusion with high calcium buffer (Ca++: 5 mM/l) significantly inhibits this stimulation.

Animals↗
PubMed1980

Evidence for an involvement of acetylcholine in self-stimulation of the prefrontal cortex in the rat.

The effects of injections of antagonists of muscarinic and nicotinic receptors on self-stimulation of the prefrontal cortex in the rat were studied. The results of this investigation suggest that acetylcholine is involved in self-stimulation of the prefrontal cortex through activation of muscarinic receptors, and also suggest a possible interaction between acetylcholine and dopamine in mediating self-stimulation of this area of the brain.

Acetylcholine↗
PubMed1980

The effect of orthostatism, passive tilting and recumbent exercise on renin release.

Three postural tests, orthostatism, passive tilting and recumbent exercise, were applied to fourteen normal volunteers. Orthostatism and tilting produce a significant increase in plasma renin activity (PRA) and plasma renin concentration (PRC), without changes in plasma renin substrate concentration (PSC). Recumbent exercise induces an inhibition of PRA and PRC and does not changes PSC. The present study seems to suggest that sympathetic activity and intravascular blood volume could play an important role in the responses of the renin-angiotensin system to postural changes.

Adult↗