Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Acta Oncol ; 62(7): 689-695, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37151105

RESUMO

BACKGROUND: Testicular cancer survivors (TCS) are at risk of Leydig cell insufficiency, which is a condition characterized by elevated luteinising hormone (LH) in combination with low levels of testosterone. It has been suggested that this condition is associated with impaired metabolic profile and low bone mineral density (BMD). The primary aim of the randomized double-blind trial NCT02991209 was to evaluate metabolic profile after 12-months testosterone replacement therapy (TRT) in TCS with mild Leydig cell insufficiency. Here we present the secondary outcomes of changes in BMD and markers of bone turnover. METHODOLOGY: In total, 69 TCS with mild Leydig cell insufficiency were randomized 1:1 to 12 months TRT (n = 35) (Tostran, gel, 2%, applied transdermally, with a maximum daily dose of 40 mg) or placebo (n = 34). BMD and markers of bone turnover were evaluated at baseline, after 6- and 12-months TRT, and 3-months post-treatment. Linear mixed effects models were used to analyse changes in BMD, N-terminal propeptide of type 1 procollagen (P1NP) and C-terminal telopeptide of type I collagen (CTX). RESULTS: After 12 months treatment, TRT was not associated with a statistically significant difference in BMD compared to placebo; total body BMD: 0.01 g/cm2 (95% confidence interval (CI): -0.01 - 0.02), BMD of the lumbar spine: 0.01 g/cm2, (95% CI: -0.01-0.03), BMD of the left femoral neck: 0.00, (95% CI: -0.01-0.02). TRT was associated with a small but statistically significant increase in P1NP: 11.65 µg/L (95% CI: 3.96, 19.35), while there was no difference in CTX. CONCLUSION: 12 months of TRT did not change BMD, while there was as small and clinically irrelevant increase in P1NP compared to placebo in TCS with mild Leydig cell insufficiency. The findings need validation in a larger cohort.


Assuntos
Densidade Óssea , Neoplasias Testiculares , Masculino , Humanos , Neoplasias Testiculares/tratamento farmacológico , Testosterona/farmacologia , Testosterona/uso terapêutico , Remodelação Óssea , Sobreviventes , Método Duplo-Cego , Biomarcadores
2.
J Med Virol ; 82(5): 861-5, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20336730

RESUMO

Human metapneumovirus (hMPV) has been described as circulating among the Uruguayan population at least since 1998 based on serologic evidence. However, no isolation attempts, molecular detection, or genetic studies have been carried out so far in the country. In the present study, molecular detection of circulating hMPV in children hospitalized with acute respiratory tract infection in Montevideo-Uruguay was carried out by reverse transcription-polymerase chain reaction (RT-PCR) amplification of the hMPV nucleoprotein (N) gene from 217 nasopharyngeal aspirates. Genetic variability analysis of the positive samples was performed by amplification and sequencing of both N and attachment glycoprotein (G) genes. Eighteen of the 217 samples tested positive for hMPV, with tachypnea, chest indrawing, and wheezing being the main clinical symptoms recorded. Phylogenetic analysis of N and G genes showed that Uruguayan samples clustered in genotypes described previously as A2, B1, and B2, with bootstrap values >or=98%. Sublineages A2a and A2b could also be distinguished within the samples that belong to A2. This is the first molecular report on the circulation of hMPV in Uruguay. The pattern of circulation of this virus, analyzed for both N and G genes independently, resembles the complex evolutionary pattern of respiratory syncytial virus (RSV).


Assuntos
Variação Genética , Metapneumovirus/classificação , Metapneumovirus/isolamento & purificação , Infecções por Paramyxoviridae/virologia , Análise por Conglomerados , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Metapneumovirus/genética , Epidemiologia Molecular , Dados de Sequência Molecular , Nasofaringe/virologia , Nucleoproteínas/genética , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Uruguai , Proteínas Estruturais Virais/genética
5.
J Clin Endocrinol Metab ; 85(10): 3589-91, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11061506

RESUMO

Recently, the presence of different polymorphisms in the regulatory region of the ob gene has been associated with variations in leptin levels. However, the results of these studies are still contradictory. The aim of the present investigation was to evaluate the presence of the A19G polymorphism in an Italian population of obese patients and to verify its association with leptin levels and anthropometric, metabolic, and clinical parameters. Two hundred five obese patients [body mass index (BMI) > 36 kg/m2; 135 women and 70 men; mean age, 46.9+/-14.23 yr] were screened for presence of the polymorphism; 61 normal-weight controls (mean BMI, 21.05 kg/m2; 53 women, 8 men) were also screened to compare polymorphism frequency. For obese patients, BMI, waist-to-hip ratio, resting energy expenditure, body composition, fasting leptin, total cholesterol, high-density lipoproteins, triglycerides, and caloric intake were determined. Genotype frequencies in obese and control subjects were compared using the contingency table chi-square test; in obese subjects an ANOVA was performed to evaluate association between the polymorphism and several clinical parameters. No significant differences in genotype distribution between control and obese subjects were found. No significant correlations were found between this polymorphism and serum leptin levels and the other parameters considered. These findings confirm the results obtained in both a Finnish and a French population; taken together, these observations might rule out a significant role for the A19->G polymorphism in the regulation of leptin levels and other clinical, anthropometric, and metabolic parameters.


Assuntos
Regiões 5' não Traduzidas/genética , Leptina/metabolismo , Obesidade/genética , Obesidade/metabolismo , Polimorfismo Genético/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antropometria , Composição Corporal/genética , Composição Corporal/fisiologia , Índice de Massa Corporal , Feminino , Testes Genéticos , Genótipo , Humanos , Itália , Masculino , Pessoa de Meia-Idade
6.
J Immunol Methods ; 186(1): 101-10, 1995 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-7561139

RESUMO

A novel method to measure target cell cytolysis based on the use of 'cold', non-radioactive chromium and on the determination of metal release by graphite furnace atomic absorption spectroscopy (FAAS) is proposed. Natural killer (NK) assays were performed by labelling target cells with chromium as Na2CrO4, and results were compared with those obtained by conventional overnight labelling with 51Cr of targets killed by the same effectors. The cytotoxic capacity of peripheral blood lymphocytes from healthy subjects was evaluated, and NK activity measured with both methods showed a good agreement at each of the tested effector to target cell ratios (between 100:1 and 1:1), with a high and significant coefficient of correlation (r = 0.931, p < 0.0001). The selection of the appropriate Cr concentrations for labelling target cells took into account both the sensitivity of our instrumentation and the possible toxic effects of the metal. A study of the effects of Cr on the cell line (K562) which is usually employed as a target in NK tests showed that Cr could have a detrimental effect on cellular function, with significant numbers of cells with depolarised mitochondria and reduced DNA synthesis after 24 h incubation using Cr levels higher than 15 mumol/l (780 micrograms/l). The method proposed here has a number of advantages, including the use of a non-radioactive tracer, limited costs, high sensitivity and reproducibility, and the possibility of storing samples. In addition, the technique uses a fixed Cr concentration which is known to be non toxic.


Assuntos
Cromo , Testes Imunológicos de Citotoxicidade/métodos , Células Matadoras Naturais/imunologia , Espectrofotometria Atômica/métodos , Adulto , Células Cultivadas , Radioisótopos de Cromo , Humanos
7.
Physiol Behav ; 70(5): 417-24, 2000 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-11110994

RESUMO

Chronic cocaine exposure during critical periods of development induces short- and long-term effects. During the pubertal period, the hypothalamic-pituitary-gonadal (HPG) axis undergoes many dynamic changes. The present study investigated whether chronic periadolescent cocaine alters reproductive maturity in the rat. Sixty female Long-Evans hooded rats were randomly assigned to one of three conditions (20 mg cocaine/kg/day, saline injected and uninjected), for dosing from postnatal day 21 (P21) through P60. Several indicators of reproductive maturation and functioning were assessed during and following treatment. Cocaine exposure had no effect on the onset of puberty or on the date of first ovulation. The number of proestrus-estrus transitions was significantly lower in cocaine-exposed females compared to uninjected females, but not compared to saline-injected controls. This reduction was observed during exposure to cocaine, as well as after the cessation of injections. During the dosing period, cocaine-exposed rats also exhibited a greater number of cycles that had no clear P-E transition than did UN subjects; this effect disappeared once injections stopped. These alterations suggest immediate, and possibly persisting, alterations in the control of ovulation after chronic cocaine exposure throughout adolescence. Interestingly, during the injection period, the saline-injected females had a significantly greater number of diestrus days compared to uninjected and cocaine-injected animals, as well as a lower proportion of regular 4- and 5-day cycles. These differences disappeared once injections stopped. These results suggest a stress-induced irregularity of the estrous cycle, possibly attenuated by cocaine and recoverable after exposure. The present findings indicate that the HPG axis is susceptible to short-term, and possibly to long-term, alterations induced by cocaine exposure throughout the adolescent period.


Assuntos
Transtornos Relacionados ao Uso de Cocaína , Cocaína/administração & dosagem , Estro/efeitos dos fármacos , Maturidade Sexual/efeitos dos fármacos , Estresse Fisiológico , Envelhecimento , Análise de Variância , Animais , Peso Corporal/efeitos dos fármacos , Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Feminino , Injeções Subcutâneas/efeitos adversos , Ovulação/efeitos dos fármacos , Periodicidade , Ratos , Ratos Long-Evans , Estresse Fisiológico/etiologia , Estresse Fisiológico/fisiopatologia
8.
Pharmacol Biochem Behav ; 50(3): 313-9, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7617667

RESUMO

Pregnant Long-Evans hooded rats were dosed with 1, 5, or 10 mg/kg per day naloxone from gestational day 7 (GD7) through GD20. The control groups included both uninjected animals and injected animals pairfed to the 10-mg dose animals. At birth, all litters were culled to four males and four females, and fostered to undosed surrogate dams. Prenatal naloxone exposure produced changes in body weight development, pain sensitivity, and motor behavior in the offspring. Five and 10 mg/kg naloxone increased adult body weights in females only, as did the pairfeeding condition. The 10 mg/kg naloxone altered pain sensitivity (in males only) as measured by the tail flick test. Animals in the 1 mg/kg dose condition habituated more rapidly than uninjected (UN) subjects in the open field, and showed less activity than UNs as they matured. Bar pressing rates were reduced in the 10 mg/kg dose males in a visual discrimination task, while 10 mg/kg males and females showed reduced bar pressing rates on differential reinforcement of low rates of responding (DRL). These findings confirm that prenatal exposure to naloxone alters some aspects of neurobehavioral development in the rat, and are consistent with the hypothesis that 1 mg/kg prenatally may increase opiate function in offspring, while 10 mg/kg prenatally may decrease opiate functioning in the offspring.


Assuntos
Comportamento Animal/efeitos dos fármacos , Naloxona/farmacologia , Antagonistas de Entorpecentes , Efeitos Tardios da Exposição Pré-Natal , Animais , Peso Corporal/efeitos dos fármacos , Cognição/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Masculino , Atividade Motora/efeitos dos fármacos , Medição da Dor , Gravidez , Desempenho Psicomotor/efeitos dos fármacos , Ratos , Reflexo/efeitos dos fármacos
9.
Minerva Endocrinol ; 15(2): 117-20, 1990.
Artigo em Italiano | MEDLINE | ID: mdl-2098652

RESUMO

Serum osteocalcin and alkaline phosphatase levels, as indexes of bone formation, and urinary calcium and hydroxyproline excretions relative to creatinine, as indexes of bone resorption, were measured in 10 obese women before and after two months of hypocaloric diet. In basal condition, serum osteocalcin, but not alkaline phosphatase levels, were higher in obese than in controls (7 +/- 0.4 vs 5.3 +/- 0.2 ng/ml). Urinary calcium/creatinine and hydroxyproline/creatinine ratios were also significantly higher than those in normals (0.37 +/- 0.05 vs 0.2 +/- 0.01 and 0.035 +/- 0.004 vs 0.02 +/- 0.002, respectively). After weight loss, serum osteocalcin significantly increased (9.5 +/- 0.5 ng/ml), while urinary calcium/creatinine and hydroxyproline/creatinine ratios fell to the normal values (0.23 +/- 0.03 and 0.026 +/- 0.001). In conclusion, it appears that obesity, at least in young women, is associated with a high bone turnover, which seems to be reversible with weight loss.


Assuntos
Reabsorção Óssea/metabolismo , Obesidade/metabolismo , Osteogênese/fisiologia , Redução de Peso , Adolescente , Adulto , Feminino , Humanos , Obesidade/tratamento farmacológico , Fatores de Tempo
10.
Minerva Endocrinol ; 15(2): 141-3, 1990.
Artigo em Italiano | MEDLINE | ID: mdl-2098656

RESUMO

High blood pressure and impaired glucose tolerance are frequently associated with obesity: it has been suggested that hyperinsulinemia could represent one of the possible pathogenetic connections between obesity and systodiastolic hypertension. In order to verify this hypothesis we examined fasting and post-load insulin and glucose levels in a group of 102 obese females, 58 hypertensive and 44 normotensive. All of the subjects underwent standard OGTT in order to measure their glycemic and insulinemic levels. No differences were found between two groups, as regard age and degree of obesity; blood pressure values were significantly different (p less than 0.01). No significative differences were detected for glycemic and insulinemic levels between hypertensive and normotensive subjects. These results indicate that hyperinsulinemia is not the prominent link between obesity and arterial hypertension; the relationship between these two conditions may be indirect.


Assuntos
Hipertensão/sangue , Insulina/sangue , Obesidade/sangue , Adulto , Glicemia/metabolismo , Feminino , Teste de Tolerância a Glucose , Humanos , Hipertensão/complicações , Obesidade/complicações
11.
Biol Trace Elem Res ; 51(1): 43-54, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8834379

RESUMO

In this work, possible interference with functional activities of human lymphocytes after in vitro treatment with selenium was examined. Sodium selenite and selenomethionine compounds were tested in parallel, and their capability to inhibit or to increase the antibody production by lymphocytes was investigated. Furthermore, after incubation for 7 d, total cell-associated Se was measured by a fluorimetric method. The in vitro doses of Se employed in this study mainly reflect those measured in blood of individuals with different Se intake. Low doses of Se (0.5-2.0 microM) added either as sodium selenite or selenomethionine did not alter the secretion of antibodies. When Se was added at higher levels, instead, an inhibitory effect was found using selenite, whereas a progressive increase in immunoglobulin production was observed after exposure to selenomethionine. In both cases, modifications were detected at 5 microM (395 micrograms Se/L), and were significant at 10 microM (789 micrograms Se/L). A different trend between the two chemical forms was also observed with regard to Se uptake by cells. Interestingly, both Se uptake and cell sensitivity were influenced by the density of the cells in culture. Our data suggest that the biological effects of Se in mammalian systems are strongly influenced by its chemical form, and caution should be exerted to avoid toxic effects of selenium.


Assuntos
Linfócitos/efeitos dos fármacos , Selenometionina/farmacologia , Selenito de Sódio/farmacologia , Células Cultivadas , Humanos , Linfócitos/metabolismo , Biossíntese de Proteínas , Selênio/farmacocinética , Selenometionina/farmacocinética , Selenito de Sódio/farmacocinética
12.
Biol Trace Elem Res ; 51(1): 23-30, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8834377

RESUMO

The purpose of our study was to investigate the relationship between plasma and hair levels of Se, Zn, and Cu, and cancer. We selected a total of 66 patients affected by either breast (38) or lung (28) cancer. They entered into the study at the onset of disease, and before any chemical or radiotherapy. Controls were randomly selected among healthy people and were matched for sex, age, smoking habits, and residence. In the group of breast cancer, a significant decrease in hair Se was found compared to controls (p < 0.01), whereas plasma Se was only slightly decreased. No difference between cases and controls was detected in both hair and plasma levels of Zn and Cu. Subjects who developed lung cancer were significantly lower in hair Zn (p < 0.05) and Cu (p < 0.01) than controls, whereas there was no difference with regard to Se. In addition, plasma Cu of these patients was increased as compared to controls.


Assuntos
Neoplasias da Mama/metabolismo , Cobre/análise , Cabelo/química , Neoplasias Pulmonares/metabolismo , Selênio/análise , Zinco/análise , Adulto , Idoso , Estudos de Casos e Controles , Cobre/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Selênio/sangue , Zinco/sangue
13.
Minerva Med ; 82(6): 345-8, 1991 Jun.
Artigo em Italiano | MEDLINE | ID: mdl-2067706

RESUMO

The incidence of impaired glucose tolerance (IGT) in obese juvenile has not yet been well defined. Glycemic and insulin responses to OGTT were evaluated in 398 obese juveniles (and 70 healthy control subjects) to investigate possible correlations with age, body mass index (BMI) and obesity duration. Subjects were subdivided into two groups according to OGTT results: obese with normal glucose tolerance (OB-NGT) and obese with impaired glucose tolerance (OB-IGT). IGT was found in 11% of subjects but no correlations were observed in relation to age, BMI and obesity duration. There was no difference in the glycemic response to OGTT in terms of the biological parameters examined. Insulin plasma levels were twice as high in OB-NGT in comparison to control subjects and OB-NGT. Basal insulinemia increased with BMI in OB-IGT but not in OB-NGT.


Assuntos
Teste de Tolerância a Glucose , Obesidade/sangue , Adolescente , Fatores Etários , Glicemia/análise , Índice de Massa Corporal , Criança , Feminino , Humanos , Insulina/sangue , Masculino
14.
Minerva Chir ; 53(10): 831-5, 1998 Oct.
Artigo em Italiano | MEDLINE | ID: mdl-9882975

RESUMO

An interesting case of perineal recurrence of rectal cancer after abdomino-perineal rectal amputation according to Miles is reported and it is emphasized how local recurrences after radical operations are a serious problem due to their frequency, the seriousness of the situation and scarce therapeutical possibilities available. The etiopathogenetical and clinical-therapeutical aspects were examined with respect to the problems of rectal neoplastic recurrence and it was noted that only aggressive surgical action, only in a very limited group of patients, increases survival, offering substantial advantages in terms of quality of life with respect to alternative therapies that have proved ineffective. The prevention of recurrence can only be achieved with suitable surgical and adjuvant medical treatment which together with an early diagnosis of the neoplastic recurrence are necessary to obtain best results.


Assuntos
Recidiva Local de Neoplasia , Neoplasias Retais/cirurgia , Evolução Fatal , Feminino , Humanos , Pessoa de Meia-Idade , Períneo
17.
J Endocrinol Invest ; 11(2): 113-8, 1988 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3361080

RESUMO

Although TRIAC is bound at least twice as avidly to nuclear receptor as T3, its thyromimetic potency is relatively low and its effect at the pituitary level on thyrotropin (TSH) secretion seems to be dissociated from that at the peripheral tissue level. In order to gain further insight into the complex effects of this thyroid hormone analog, we studied the effects of long-term TRIAC administration (2.8 mg/day for 2 months) on TSH secretion, circulating free thyroid hormone (FT4 and FT3) levels and some parameters able to evaluate the peripheral thyroid hormone action, in 5 mild obese subjects on low caloric diet (1200 kcal/day). The results were compared to those obtained in 5 mild obese subjects matched for age, sex and weight on low caloric diet alone. TRIAC administration completely inhibited the secretion of both basal and TRH-stimulated TSH in few days, and consequently serum FT4 and FT3 concentrations progressively dropped to very low levels, while no significant changes in both TSH and free thyroid hormone levels were recorded in the control group. The body weight significantly fell in both groups, without any difference between TRIAC treated and untreated patients. The heart rate was constant throughout the course of the study in both groups of patients. Serum total cholesterol, triglyceride and total lipid concentrations significantly decreased in both groups, and the decrement recorded in TRIAC treated patients was not significantly different from that found in patients on diet alone.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Obesidade/metabolismo , Glândula Tireoide/efeitos dos fármacos , Tri-Iodotironina/análogos & derivados , Adulto , Peso Corporal , Método Duplo-Cego , Feminino , Frequência Cardíaca , Humanos , Lipídeos/sangue , Distribuição Aleatória , Globulina de Ligação a Hormônio Sexual/análise , Testes de Função Tireóidea , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue , Tri-Iodotironina/farmacologia
18.
Clin Endocrinol (Oxf) ; 48(6): 769-75, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9713567

RESUMO

OBJECTIVE: It is unclear whether the blunted GH secretion in Prader-Willi Syndrome (PWS) is a true deficiency, or merely secondary to obesity. We have investigated the role of obesity in the blunted GH secretion in PWS. DESIGN: We studied the GH response to a combined administration of GHRH (1 microgram/kg i.v. at 0 min) and pyridostigmine (PD) (60 and 120 mg by mouth for children and adults, respectively, at time -60 min), as well as the baseline IGF-I levels, in a group of patients with PWS. Two different control groups were studied with GHRH + PD using the same doses and methods as above: prepubertal and pubertal obese subjects, and prepubertal short normal children. Moreover, in 14 patients with PWS and in the group of short normals the GH response to at least two stimulation tests (insulin tolerance test, clonidine, L-dopa, arginine) had been previously determined. PATIENTS: Twenty-two PWS patients (10 males and 12 females), 21 with essential obesity (11 males and 10 females), and eight short normal children (4 males and 4 females) were studied after obtaining informed consent. MEASUREMENTS: Blood samples were taken at -60, -30 and 0 min and then 15, 30, 45, 60, 90 and 120 min after GHRH administration. Serum GH was measured in duplicate by IRMA, and IGF-I by RIA after acid ethanol extraction. Statistical analysis was performed by t-test for unpaired data, and analysis of variance for parametric or nonparametric data, where appropriate. RESULTS: The GH response to GHRH + PD was significantly lower in PWS patients (AUC: mean +/- SE: 599 +/- 99 micrograms/l/h) if compared with either short normal children (3294 +/- 461 micrograms/l/h: P < 0.0001) or obese subjects (1445 +/- 210 micrograms/l/h: P < 0.005). Low IGF-I concentrations were found in all PWS patients, so that PWS group had mean IGF-I levels significantly lower than the other groups. CONCLUSIONS: Our results showed that subjects with PWS had a reduced GH responsiveness to GHRH + PD associated with subnormal IGF-I levels. These findings suggested that short stature in PWS may be at least partially correlated to the presence of GH deficiency, and that impaired GH secretion is not secondary to obesity.


Assuntos
Inibidores da Colinesterase , Hormônio Liberador de Hormônio do Crescimento , Hormônio do Crescimento/sangue , Síndrome de Prader-Willi/sangue , Brometo de Piridostigmina , Adolescente , Adulto , Criança , Feminino , Transtornos do Crescimento/sangue , Humanos , Fator de Crescimento Insulin-Like I/análise , Masculino , Obesidade/sangue
19.
J Endocrinol Invest ; 8(4): 337-41, 1985 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-4067205

RESUMO

The effect of melatonin on PRL secretion has not been established yet. In an attempt to establish whether PRL response to melatonin changes in relation to the photoperiods of the day and pubertal maturation, we evaluated PRL plasma levels after melatonin administration in 19 prepubertal and pubertal healthy subjects of both sexes in two different periods of the day: in the morning, when the sensitivity to melatonin is low, and in the afternoon, when the responsiveness to melatonin is higher. Melatonin was given im at a dose of 0.2 mg/kg BW PRL plasma levels were determined with double antibody RIA method. When melatonin was administered in the morning, all pubertal subjects and 7 of 9 prepubertal ones showed no significant variation of PRL levels; a significant decrease was observed in the other 2 prepubertal subjects. On the contrary, when melatonin was given in the afternoon, a significant increase in PRL plasma levels was seen in all pubertal subjects; no significant changes were found in 6 prepubertal ones, while in the other 3 a marked decrease could be observed. The results reveal that the response of PRL to melatonin depends upon the times of day of administration and on pubertal development.


Assuntos
Luz , Melatonina/farmacologia , Periodicidade , Prolactina/metabolismo , Puberdade , Adolescente , Criança , Feminino , Humanos , Masculino , Prolactina/sangue , Radioimunoensaio , Fatores de Tempo
20.
Acta Endocrinol (Copenh) ; 111(3): 305-11, 1986 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-3083625

RESUMO

It is well known that the pineal gland can modulate the secretion of pituitary hormones. Melatonin, the main hormone produced by the pineal gland, acts at the hypothalamic site, whereas hypophyseal sensitivity to melatonin seems to change with age. To investigate the influence of pubertal development on the role of the pineal gland in the regulation of the secretion of pituitary hormones, FSH, LH, Prl, TSH and GH responses to melatonin were evaluated in a group of 9 prepubertal and 10 pubertal healthy subjects of both sexes. Melatonin was given im at a dose of 0.2 mg/kg body weight at 3 p.m. Venous blood samples were drawn -20, 0, 20, 40, 60, 90, 120, 180 and 240 min, after melatonin injection. According to the same experimental protocol, venous blood samples were collected during a saline infusion on a separate occasion. FSH, LH, Prl, TSH and GH plasma levels were measured with RIA. In pubertal subjects, a significant rise in the mean Prl levels was seen 90 min after melatonin as compared with those during saline infusion. The Prl melatonin response area was significantly lower in prepubertal treated subjects and significantly higher in pubertal ones compared with the respective controls. The mean GH values showed a significant decrease 120 min after melatonin only in prepubertal subjects; no significant variations were seen in 8 of 10 pubertal subjects, whereas in the last 2 a marked increase was observed.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Melatonina/farmacologia , Hormônios Adeno-Hipofisários/metabolismo , Puberdade , Adolescente , Criança , Feminino , Hormônio Foliculoestimulante/metabolismo , Hormônio do Crescimento/metabolismo , Humanos , Injeções Intramusculares , Hormônio Luteinizante/metabolismo , Masculino , Melatonina/administração & dosagem , Prolactina/metabolismo , Tireotropina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA