Hypothalamic-pituitary-gonadal function in men with liver cirrhosis before and after liver transplantation

Objective: To evaluate the influence of end-stage liver disease and orthotopic liver transplantation in the pituitary function and hormone metabolism before and after liver transplantation.Methods: In a prospective study, serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and prolactin (PRL) of 30 male patients with cirrhosis were determined two to four hours before and six months after liver transplantation. The results were compared according to the Model for End-stage Liver Disease (MELD).Results: male patients with liver cirrhosis have hypogonadism. FSH was normal, but inappropriately low due to androgen failure; E2 and PRL, on their turn, were high. After liver transplantation, FSH and LH levels increased (p < 0.05), whereas E2 and PRL normalized (p < 0.05). The MELD score did not influence changes in FSH, PRL and LH, however, the more severe the cirrhosis was, the more significant was the normalization of E2 (p = 0.01).Conclusion: Patients with cirrhosis and male hypogonadism have inappropriately normal levels of FSH and LH, associated with an increase in E2 and LRP. After liver transplantation, FSH and LH increased, while E2 and PRL returned to normal. Changes in E2 levels were most pronounced in patients with MELD > 18. The severity of cirrhosis had no influence on FSH, PRL and LH.

Trypanosoma vivax nos tecidos testicular e epididimário de ovinos experimentalmente infectados

Quatro ovinos machos, com cerca de 12 meses de idade (Ovinos 1-4), foram infectados por via intravenosa com aproximadamente 1,25x10(5) tripomastigotas de Trypanosoma vivax, outros quatro ovinos (Ovinos 5-8) destinaram-se ao grupo controle. Após a infecção, exames clínicos visando avaliar temperatura retal, freqüências cardíaca e respiratória e parasitemia foram realizados diariamente por 30 dias, tempo estabelecido para o término do experimento. A avaliação do hematócrito foi realizada a cada cinco dias. Ao final do período experimental, os animais foram castrados e os testículos e epidídimos submetidos ao exame anatomopatológico. Amostras destes órgãos dos Ovinos 1, 4 e 5 foram tomadas para a realização da reação em cadeia da polimerase (PCR). Os parâmetros clínicos (hipertermia, aumento das freqüências cardíaca e respiratória, aumento de volume dos linfonodos e palidez das mucosas) mantiveram-se para o grupo infectado acima dos valores mostrados pelo grupo controle durante todo o período experimental. A parasitemia foi observada a partir do 3º dia pós-infecção (dpi) com picos nos 6-10os dpi e nos 15-18os dpi. Os Ovinos 1 e 4 apresentaram, a partir do 25º dpi, anemia acentuada. Macroscopicamente, todos os testículos dos animais do grupo infectado apresentaram-se flácidos e com coloração pálida. Microscopicamente, observaram-se degeneração testicular moderada a acentuada, epididimite multifocal e hiperplasia do epitélio epididimário. A análise por PCR de T. vivax nos tecidos testicular e epididimário resultou em 100% de positividade para ovinos infectados experimentalmente. As lesões epididimárias e testiculares associadas à presença do parasita nesses órgãos, detectada por PCR, sugerem a participação do parasita no mecanismo etiopatogênico de danos reprodutivos.

Influence of the bipartite scrotum on the testicular and scrotal temperatures in goats

The influence of the scrotal bipartition and of the year period on the scrotal-testicular thermal regulation was evaluated in male goats raised in Piaui State, Brazil. Eighteen male goats at mating age were accomplished in this study and arranged into three Groups (6 animals each) obeying the classification as goats presenting no scrotal bipartition (Group I), goats showing scrotal bipartition at 50% of the testicular length (Group II), and goats with more than 50% of scrotal bipartition (Group III). The scrotal, testicular and spermatic funiculi temperatures were evaluated invasively with the aid of a digital thermometer and non-invasive with a pyrometer in the proximal, medial and distal portion. The data were acquired during the dry (October-November) and rainy (February-March) period of the year, measured in two shifts: morning (6h00-7h00) and afternoon (14h00-15h00). The results were submitted to variance analysis (ANOVA) following the SNK test for average comparison (p<0.05). The year period interfered on the scrotal-testicular thermal regulation, due to increased temperatures of the scrotal, testicular and spermatic funiculi during the dry period in comparison with the rainy period. The bipartition level was also a factor which contributed to the influence of scrotal-testicular temperature regulation, due to lower average scrotal-testicular temperature rates observed during both periods in the goats with higher levels of scrotal bipartition (>50%). It is possible to conclude that with the experimental conditions applied on this study, the level of scrotal bipartition and the climatic conditions interfere with the scrotal-testicular thermal regulation in goats.

Cortisol influence on testicular testosterone secretion in domestic cat: An in vitro study

The aim of the present experiment was to investigate the effect of corticosteroids (exogen) on in vitro testosterone secretion after stress by transportation (40 minutes). Feline testes (Felis silvestris catus) were incubated in the following media: TCM 199; TCM 199 + hCG 10_7M; TCM 199 + hydrocortisone 10_7M, or TCM 199 + hCG + hydrocortisone. The animals (n=21) were allocated into three groups: (S) that arrived at 3 h prior to surgery, (A) that remained in the laboratory for 36 h before being submitted to surgical procedure, and (C) that were also allowed to remain for 36 hours in the laboratory before the surgical procedure, but whose testes had been incubated with hydrocortisone prior to incubation in the referred media. The results showed that group S secreted higher levels of testosterone, regardless of the culture media. It is noteworthy that the suppressing action of hydrocortisone sodium succinate led to a reduction in the testosterone concentration, despite the presence of hCG.

Goat scrotal-testicular biometry: Influence of the season on scrotal bipartition

The scrotal-testicular biometry was evaluated in goats raised in Piaui state, Brazil, presenting different levels of scrotal division, in rainy and dry periods of the year. For this study, eighteen male goats at mating age were accomplished and arranged into three groups (6 animals each), obeying the classification as goats with no scrotal bipartition (GI), goats showing scrotal bipartition up to 50% of testicular length (GII), and goats with more than 50% of scrotal bipartition (GIII). The biometry of the scrotal-testicular was made evaluating the scrotal length (SL), scrotal circumference (SC), testicular length (TL) and testicular volume (TV). The results were evaluated following the variance analysis (ANOVA) and the SNK test applied on the average comparisons. The analysis of the data demonstrated high values, in dry and rainy periods, of SC (24.63cm/ 26.97cm), SL (16.61cm/ 18.24cm), TL (5.32cm/ 5.93cm), TV (173.81cm³/ 203.01cm³). This supports the hypothesis of the influence of the period of the year and of the scrotal bipartition on the scrotal-testicular biometry in goat.

Desenvolvimento corporal e testicular em machos de codornas de corte e de postura de 25 a 360 dias

Codornas do tipo carne e tipo ovos foram analisadas para determinar o desenvolvimento reprodutivo, a puberdade e o início da senilidade. Para tal, 288 codornas (144 codornas de corte e 144 de postura) foram acompanhadas desde a eclosão até os 360 dias de idade. As aves foram distribuídas por idade em 18 grupos, sendo 8 codornas/grupo/tipo de codorna. Após 35 dias as codornas foram mantidas em condições de fotoperíodo de dias longos (17luz: 7escuro). O peso vivo e os valores morfométricos e histológicos testiculares foram determinados em cada período. Os dados obtidos foram analisados para determinar a curva de crescimento e o comportamento dos parâmetros analisados. O modelo que mais se adequou aos dados foi o modelo não linear de Gompertz (Y=A exp [-B e (-kt)]). O peso vivo e as características testiculares macro e microscópicas apresentaram comportamento alométrico entre si, sendo que, aproximadamente aos 60 dias os machos apresentaram-se sexualmente desenvolvidos, e estabilizaram o peso corporal por volta dos 100 dias. O testículo direito é mais cranial que o esquerdo e diferem em relação a comprimento e largura, porém não foi observada diferenças (P>0,05) para peso testicular. As codornas de corte apresentaram peso corporal e peso testicular maiores que as codornas de postura, porém as codornas de postura apresentaram peso relativo testicular maior. Durante todo o período analisado os machos puderam ser considerados sexualmente aptos. Os reprodutores apresentaram características sexuais ativas até os 360 dias de idade, representadas pelo tamanho testicular e pela atividade celular nos túbulos seminíferos.

Análise quantitativa da ecogenicidade testicular pela técnica do histograma de ovinos da baixada ocidental maranhense

A ultrassonografia é um método de diagnóstico por imagem que permite a avaliação de diferentes órgãos e estruturas corpóreas de maneira não invasiva. No entanto, a avaliação subjetiva das imagens caracteriza um dos grandes entraves na utilização desta técnica de diagnóstico, havendo necessidade de mecanismos que minimizem a subjetividade do exame e a divergência na interpretação dos achados ultrassonográficos. Desta forma este trabalho objetivou caracterizar a ecogenicidade do parênquima e mediastino testicular de ovinos utilizando a técnica do histograma escala-cinza. Foram utilizados 30 animais divididos em três grupos de acordo com a faixa etária (FE): de três a seis meses (FE1), sete a 12 meses (FE2), 13 a 18 meses (FE3) e realizadas varreduras testiculares nos planos frontal, sagital e transversal, elaborando ao final um histograma a partir das imagens ultrassonográficas. Observou-se que tanto a ecogenicidade do parênquima quanto a do mediastino testicular aumentaram gradativamente com a progressão das idades dos animais, com média e desvio-padrão de 95,00±19,05 e 94,35±18,82 para a ecogenicidade do parênquima do antímero direito e esquerdo, respectivamente, e 127,95±12,97 para o mediastino direito e 126,59±11,78 para o esquerdo. A técnica do histograma escala-cinza demonstrou ser um método eficiente na determinação da ecogenicidade testicular, possibilitando o estabelecimento de padrões de normalidade que venham a auxiliar pesquisas futuras no monitoramento do desenvolvimento testicular bem como na detecção de patologias. Para a regimes exclusivos de criação extensiva, como na baixada maranhense, representa ferramenta valiosa para sua utilização em projetos sociais do Estado que atendem a agricultura familiar.

Influência da estação do ano sobre a estrutura testicular em ovinos explorados no sul do Estado do Piauí

RESUMO: Objetivou-se avaliar a influência da estação do ano sobre a estrutura testicular de ovinos SRD. Foram utilizados 10 animais com idade entre dois e três anos. Os testículos foram seccionados e fixados em solução de Bouin por 24h. Os fragmentos foram submetidos ao processamento histológico, emblocados em parafina e corados com hematoxilina eosina. Foram avaliadas a proporção volumétrica dos compartimentos testiculares, o diâmetro dos túbulos seminíferos, altura do epitélio seminífero e frequências dos estágios do ciclo do epitélio seminíferos. Os dados foram submetidos à análise de variância a 5% de probabilidade, do programa estatístico SAS 9.0. Os resultados revelaram todos os valores pesquisados sofreram influência da estação do ano. O valor do diâmetro tubular foi de 143,98±17,83 e 170,37±26,64μm, a altura do epitélio seminífero foi de 44,92±9,23 e 50,06±13,61μm e a proporção volumétrica foi de 78,32±13,68 e 80,13±15,14% nos períodos seco e chuvoso, respectivamente. A quantificação das células germinativas e de Sertoli mostrou todos os valores foram maiores no período chuvoso quando comparados com o seco. Concluiu-se que a estação do ano interferiu na estrutura testicular, tendo em vista que todos os valores da proporção volumétrica dos componentes testiculares mostraram diferença significativa entre as estações do ano, pois os valores foram mais acentuados no período chuvoso.

Single axis controlled attraction type magnetic bearing

This paper presents a new type of magnetic bearing with active control only in axial direction. The bearing uses two pairs of permanent magnets working in attraction mode to restrict the radial motion and a control system composed of two electromagnets, a gap sensor and a controller to keep the axis in a fixed axial position. The principle, the dynamic model for axial motion and the control system for this bearing are presented. Finally, by experiments conducted in a prototype, the effectiveness of the presented concept is shown.

Correlations between ANP concentrations in atria, plasma and cerebral structures and sodium chloride preference in Wistar rats

We determined whether ANP (atrial natriuretic peptide) concentrations, measured by radioimmunoassay, in the ANPergic cerebral regions involved in regulation of sodium intake and excretion and pituitary gland correlated with differences in sodium preference among 40 Wistar male rats (180-220 g). Sodium preference was measured as mean spontaneous ingestion of 1.5% NaCl solution during a test period of 12 days. The relevant tissues included the olfactory bulb (OB), the posterior and anterior lobes of the pituitary gland (PP and AP, respectively), the median eminence (ME), the medial basal hypothalamus (MBH), and the region anteroventral to the third ventricle (AV3V). We also measured ANP content in the right (RA) and left atrium (LA) and plasma. The concentrations of ANP in the OB and the AP were correlated with sodium ingestion during the preceding 24 h, since an increase of ANP in these structures was associated with a reduced ingestion and vice-versa (OB: r = -0.3649, P<0.05; AP: r = -0.3291, P<0.05). Moreover, the AP exhibited a correlation between ANP concentration and mean NaCl intake (r = -0.4165, P<0.05), but this was not the case for the OB (r = 0.2422). This suggests that differences in sodium preference among individual male rats can be related to variations of AP ANP level. Earlier studies indicated that the OB is involved in the control of NaCl ingestion. Our data suggest that the OB ANP level may play a role mainly in day-to-day variations of sodium ingestion in the individual rat

Effects of bromocriptine on serum prolactin levels, pituitary weight and immunoreactive prolactin cells in estradiol-treated ovariectomized rats: an experimental model of estrogen-dependent hyperprolactinemia

The present study was designed to assess the effects of bromocriptine, a dopamine agonist, on pituitary wet weight, number of immunoreactive prolactin cells and serum prolactin concentrations in estradiol-treated rats. Ovariectomized Wistar rats were injected subcutaneously with sunflower oil vehicle or estradiol valerate (50 or 300 µg rat-1 week-1) for 2, 4 or 10 weeks. Bromocriptine (0.2 or 0.6 mg rat-1 day-1) was injected daily during the last 5 or 12 days of estrogen treatment. Data were compared with those obtained for intact control rats. Administration of both doses of estrogen increased serum prolactin levels. No difference in the number of prolactin cells in rats treated with 50 µg estradiol valerate was observed compared to intact adult animals. In contrast, rats treated with 300 µg estradiol valerate showed a significant increase in the number of prolactin cells (P<0.05). Therefore, the increase in serum prolactin levels observed in rats treated with 50 µg estradiol valerate, in the absence of morphological changes in the pituitary cells, suggests a "functional" estrogen-induced hyperprolactinemia. Bromocriptine decreased prolactin levels in all estrogen-treated rats. The administration of this drug to rats previously treated with 300 µg estradiol valerate also resulted in a significant decrease in pituitary weight and number of prolactin cells when compared to the group treated with estradiol alone. The general antiprolactinemic and antiproliferative pituitary effects of bromocriptine treatment reported here validate the experimental model of estrogen-induced hyperprolactinemic rats

Neuroendocrine regulation of salt and water metabolism

Neurons which release atrial natriuretic peptide (ANPergic neurons) have their cell bodies in the paraventricular nucleus and in a region extending rostrally and ventrally to the anteroventral third ventricular (AV3V) region with axons which project to the median eminence and neural lobe of the pituitary gland. These neurons act to inhibit water and salt intake by blocking the action of angiotensin II. They also act, after their release into hypophyseal portal vessels, to inhibit stress-induced ACTH release, to augment prolactin release, and to inhibit the release of LHRH and growth hormone-releasing hormone. Stimulation of neurons in the AV3V region causes natriuresis and an increase in circulating ANP, whereas lesions in the AV3V region and caudally in the median eminence or neural lobe decrease resting ANP release and the response to blood volume expansion. The ANP neurons play a crucial role in blood volume expansion-induced release of ANP and natriuresis since this response can be blocked by intraventricular (3V) injection of antisera directed against the peptide. Blood volume expansion activates baroreceptor input via the carotid, aortic and renal baroreceptors, which provides stimulation of noradrenergic neurons in the locus coeruleus and possibly also serotonergic neurons in the raphe nuclei. These project to the hypothalamus to activate cholinergic neurons which then stimulate the ANPergic neurons. The ANP neurons stimulate the oxytocinergic neurons in the paraventricular and supraoptic nuclei to release oxytocin from the neural lobe which circulates to the atria to stimulate the release of ANP. ANP causes a rapid reduction in effective circulating blood volume by releasing cyclic GMP which dilates peripheral vessels and also acts within the heart to slow its rate and atrial force of contraction. The released ANP circulates to the kidney where it acts through cyclic GMP to produce natriuresis and a return to normal blood volume

Interaction between NO and oxytocin: Influence on LHRH release

Nitric oxide synthase (NOS)-containing neurons have been localized in various parts of the CNS. These neurons occur in the hypothalamus, mostly in the paraventricular and supraoptic nuclei and their axons project to the neural lobe of the pituitary gland. We have found that nitric oxide (NO) controls luteinizing hormone-releasing hormone (LHRH) release from the hypothalamus acting as a signal transducer in norepinephrine (NE)-induced LHRH release. LHRH not only releases LH from the pituitary but also induces sexual behavior. On the other hand, it is known that oxytocin also stimulates mating behavior and there is some evidence that oxytocin can increase NE release. Therefore, it occurred to us that oxytocin may also stimulate LHRH release via NE and NO. To test this hypothesis, we incubated medial basal hypothalamic (MBH) explants from adult male rats in vitro. Following a preincubation period of 30 min, MBH fragments were incubated in Krebs-Ringer bicarbonate buffer in the presence of various concentrations of oxytocin. Oxytocin released LHRH at concentrations ranging from 0.1 nM to 1 µM with a maximal stimulatory effect (P<0.001) at 0.1 µM, but with no stimulatory effect at 10 µM. That these effects were mediated by NO was shown by the fact that incubation of the tissues with NG-monomethyl-L-arginine (NMMA), a competitive inhibitor of NOS, blocked the stimulatory effects. Furthermore, the release of LHRH by oxytocin was also blocked by prazocin, an a1-adrenergic receptor antagonist, indicating that NE mediated this effect. Oxytocin at the same concentrations also increased the activity of NOS (P<0.01) as measured by the conversion of [14C]arginine to citrulline, which is produced in equimolar amounts with NO by the action of NOS. The release of LHRH induced by oxytocin was also accompanied by a significant (P<0.02) increase in the release of prostaglandin E2 (PGE2), a mediator of LHRH release that is released by NO. On the other hand, incubation of neural lobes with various concentrations of sodium nitroprusside (NP) (300 or 600 µM), a releaser of NO, revealed that NO acts to suppress (P<0.01) the release of oxytocin. Therefore, our results indicate that oxytocin releases LHRH by stimulating NOS via NE, resulting in an increased release of NO, which increases PGE2 release that in turn induces LHRH release. Furthermore, the released NO can act back on oxytocinergic terminals to suppress the release of oxytocin in an ultrashort-loop negative feedback

Dose-dependent effects of 17-ß-estradiol on pituitary thyrotropin content and secretion in vitro

We studied the basal and thyrotropin-releasing hormone (TRH) (50 nM) induced thyrotropin (TSH) release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-ß-estradiol benzoate (EB; sc, daily for 10 days) or with vehicle (untreated control rats, OVX). One group was sham-operated (normal control). The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4, at 37oC in an atmosphere of 95% O2/5% CO2. Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3). Ovariectomy induced a decrease (P<0.05) in basal TSH release (normal control = 44.1 ± 7.2; OVX = 14.7 ± 3.0 ng/ml) and tended to reduce TRH-stimulated TSH release (normal control = 33.0 ± 8.1; OVX = 16.6 ± 2.4 ng/ml). The lowest dose of EB (0.7 µg/100 g body weight) did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 ± 0.06 µg/hemipituitary; P<0.05) above that of OVX (0.4 ± 0.03 µg/hemipituitary) and normal rats (0.46 ± 0.03 µg/hemipituitary). The intermediate EB dose (1.4 µg/100 g body weight) induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 µg/100 g body weight), serum 17-ß-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P<0.05) reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the TSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses

Effects of estradiol benzoate on 5'-iodothyronine deiodinase activities in female rat anterior pituitary gland, liver and thyroid gland

There is little information on the possible effects of estrogen on the activity of 5'-deiodinase (5'-ID), an enzyme responsible for the generation of T3, the biologically active thyroid hormone. In the present study, anterior pituitary sonicates or hepatic and thyroid microsomes from ovariectomized (OVX) rats treated or not with estradiol benzoate (EB, 0.7 or 14 µg/100 g body weight, sc, for 10 days) were assayed for type I 5'-ID (5'-ID-I) and type II 5'-ID (5'-ID-II, only in pituitary) activities. The 5'-ID activity was evaluated by the release of 125I from deiodinated 125I rT3, using specific assay conditions for type I or type II. Serum TSH and free T3 and free T4 were measured by radioimmunoassay. OVX alone induced a reduction in pituitary 5'-ID-I (control = 723.7 ± 67.9 vs OVX = 413.9 ± 26.9; P<0.05), while the EB-treated OVX group showed activity similar to that of the normal group. Thyroid 5'-ID-I showed the same pattern of changes, but these changes were not statistically significant. Pituitary and hepatic 5'-ID-II did not show major alterations. The treatment with the higher EB dose (14 µg), contrary to the results obtained with the lower dose, had no effect on the reduced pituitary 5'-ID-I of OVX rats. However, it induced an important increment of 5'-ID-I in the thyroid gland (0.8 times higher than that of the normal group: control = 131.9 ± 23.7 vs ovx + EB 14 µg = 248.0 ± 31.2; P<0.05), which is associated with increased serum TSH (0.6-fold vs OVX, P<0.05) but normal serum free T3 and free T4. The data suggest that estrogen is a physiological stimulator of anterior pituitary 5'-ID-I and a potent stimulator of the thyroid enzyme when employed at high doses