Altered microRNA profiles of testicular biopsies from patients with nonobstructive azoospermia / 亚洲男科学杂志(英文版)

Many studies have shown that microRNAs (miRNAs) play vital roles during the spermatogenesis. However, little is known about the altered miRNA profiles of testicular tissues in nonobstructive azoospermia (NOA). Using microarray technology, the miRNA expression profiles of testicular biopsies from patients with NOA and of normal testicular tissues were determined. Bioinformatics analyses were conducted to predict the enriched biological processes and functions of identified miRNAs. The microarray data were validated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), the results of which were then validated with a larger sample size. Correlations between the miRNA expression levels and clinical characteristics were analyzed. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic ability of miRNAs for azoospermia. Hierarchical clustering showed that 129 miRNAs were significantly differentially expressed between the NOA and control groups. Bioinformatics analysis indicated that the differentially expressed miRNAs were involved in spermatogenesis, cell cycle, and mitotic prometaphase. In the subsequent qRT-PCR assays, the selected miRNA expression levels were consistent with the microarray results, and similar validated results were obtained with a larger sample size. Some clinical characteristics were significantly associated with the expression of certain miRNAs. In particular, we identified a combination of two miRNAs (miR-10b-3p and miR-34b-5p) that could serve as a predictive biomarker of azoospermia. This study provides altered miRNA profiles of testicular biopsies from NOA patients and examines the roles of miRNAs in spermatogenesis. These profiles may be useful for predicting and diagnosing the presence of testicular sperm in individuals with azoospermia.

La esteroidogénesis en el síndrome de ovarios poliquísticos / Steroidogenesis in polycystic ovary syndrome

Resumen El síndrome de ovarios poliquísticos es la enfermedad endocrina más frecuente en la edad reproductiva; se caracteriza por alteraciones menstruales, hiperandrogenismo clínico o bioquímico e identificación ultrasonográfica de quistes ováricos. Las alteraciones neuroendocrinas y metabólicas que lo acompañan implican desensibilización del eje hipotálamo-hipófisis-ovario, esteroidogénesis e hiperandrogenismo. Recientemente se ha explorado el papel de la resistencia a la insulina. Se ha establecido que la principal causa del síndrome de ovarios poliquísticos es el hiperandrogenismo, debido a alteraciones enzimáticas en la vía esteroidogénica, por lo que existe sobreestimulación por parte de la hormona luteinizante a causa de los pulsos rápidos generados por la hormona liberadora de gonadotropinas. Diversos factores de crecimiento y citocinas inhiben la conversión de andrógenos a estrógenos. En la desregulación característica de este síndrome también están involucradas la activina y las prostaglandinas e, incluso, altos niveles de insulina.

Abstract Polycystic ovary syndrome is the most common endocrine disease in reproductive age, characterized by menstrual alterations, clinical or biochemical hyperandrogenism, and ultrasound-identified ovarian cysts. The neuroendocrine and metabolic alterations that accompany this condition involve the desensitization of the hypothalamus-pituitary-ovary axis, steroidogenesis and hyperandrogenism; recently, the role of insulin resistance has been explored. Hyperandrogenism has been established to be the main cause of polycystic ovary syndrome, due to enzymatic alterations in the steroidogenic pathway that cause luteinizing hormone over-stimulation because of quick pulses generated by gonadotropin-releasing hormones. Various growth factors of and cytokines inhibit the conversion of androgens into estrogens; activin and prostaglandins are also involved, even high levels of insulin participate in the characteristic deregulation of this syndrome.

Hypothalamic transcriptional expression of the kisspeptin system and sex steroid receptors differs among polycystic ovary syndrome rat models with different endocrine phenotypes

OBJECTIVES: Polycystic ovary syndrome is a heterogeneous endocrine disorder that affects reproductive-age women. The mechanisms underlying the endocrine heterogeneity and neuroendocrinology of polycystic ovary syndrome are still unclear. In this study, we investigated the expression of the kisspeptin system and gonadotropin-releasing hormone pulse regulators in the hypothalamus as well as factors related to luteinizing hormone secretion in the pituitary of polycystic ovary syndrome rat models induced by testosterone or estradiol. METHODS: A single injection of testosterone propionate (1.25 mg) (n=10) or estradiol benzoate (0.5 mg) (n=10) was administered to female rats at 2 days of age to induce experimental polycystic ovary syndrome. Controls were injected with a vehicle (n=10). Animals were euthanized at 90-94 days of age, and the hypothalamus and pituitary gland were used for gene expression analysis. RESULTS: Rats exposed to testosterone exhibited increased transcriptional expression of the androgen receptor and estrogen receptor-β and reduced expression of kisspeptin in the hypothalamus. However, rats exposed to estradiol did not show any significant changes in hormone levels relative to controls but exhibited hypothalamic downregulation of kisspeptin, tachykinin 3 and estrogen receptor-α genes and upregulation of the gene that encodes the kisspeptin receptor. CONCLUSIONS: Testosterone- and estradiol-exposed rats with different endocrine phenotypes showed differential transcriptional expression of members of the kisspeptin system and sex steroid receptors in the hypothalamus. These differences might account for the different endocrine phenotypes found in testosterone- and estradiol-induced polycystic ovary syndrome rats.

Biochemical evaluation in human saliva with special reference to ovulation detection.

Aim : The aim of the present study was to investigate the level of salivary sialic acids and glycosaminoglycans with reference to salivary hormones during the normal menstrual cycle. Settings and Design: Fifty women volunteers were selected for the present study. Materials and Methods : Saliva was collected from 50 women and ovulation was detected in women with normal menstrual cycles through basal body temperature (BBT), ultrasound and salivary ferning. Samples were divided into five categories, as prepubertal (6-9 years), pre-ovulatory phase (6-12 days), ovulatory phase (13-14 days), postovulatory phase (15-26 days) and menopause (above 45 years). Each sample was subjected to evaluation of the sialic acids and glycosaminoglycans along with salivary hormones. Results : The result revealed that the ovulatory phase has increased sialic acid and glycosaminoglycans during the menstrual cycle when compared with that of the other phases. Consequently, an increased level of hormones such as luteinizing hormone and estrogen during the ovulatory period when compared to that of the pre-ovulatory and postovulatory periods appeared to be noteworthy. Statistically, analysis was performed using one way-ANOVA (LSD; post hoc method) to determine the significance as P < 0.001, 0.01, 0.05 in between the reproductive phases of the menstrual cycle. Conclusion : This study concluded that saliva-specific carbohydrates in the ovulatory saliva make the possibility to develop a biomarker for detection of ovulation by non-invasive methods.

Leydig cells, thyroid hormones and steroidogenesis.

Leydig cells are the primary source of androgens in the mammalian testis. It is established that the luteinizing hormone (LH) produced by the anterior pituitary is required to maintain the structure and function of the Leydig cells in the postnatal testis. Until recent years, a role by the thyroid hormones on Leydig cells was not documented. It is evident now that thyroid hormones perform many functions in Leydig cells. For the process of postnatal Leydig cell differentiation, thyroid hormones are crucial. Thyroid hormones acutely stimulate Leydig cell steroidogenesis. Thyroid hormones cause proliferation of the cytoplasmic organelle peroxisome and stimulate the production of steroidogenic acute regulatory protein (StAR) and StAR mRNA in Leydig cells; both peroxisomes and StAR are linked with the transport of cholesterol, the obligatory intermediate in steroid hormone biosynthesis, into mitochondria. The presence of thyroid hormone receptors in Leydig cells and other cell types of the Leydig lineage is an issue that needs to be fully addressed in future studies. As thyroid hormones regulate many functions of Sertoli cells and the Sertoli cells regulate certain functions of Leydig cells, effects of thyroid hormones on Leydig cells mediated via the Sertoli cells are also reviewed in this paper. Additionally, out of all cell types in the testis, the thyrotropin releasing hormone (TRH), TRH mRNA and TRH receptor are present exclusively in Leydig cells. However, whether Leydig cells have a regulatory role on the hypothalamo-pituitary-thyroid axis is currently unknown.

Effect of simultaneous exposure to lead and cadmium on gonadotropin binding and steroidogenesis on granulosa cells: an in vitro study.

Effects of lead (Pb) and cadmium (Cd) both alone or in combination on the binding of LH and FSH on isolated granulosa cells were studied. Granulosa cells isolated from proestrous rats were incubated (in vitro) with lead acetate and/or cadmium acetate (0.03 microM of Pb or Cd) for 1 hr. LH binding was dropped to 84% in Pb treated cells, 72.5% in Cd treated cells and 74.8% in combined metal treated cells compared to control. FSH binding dropped to 85.5% in Pb treated cells, 71.16% in Cd treated cells and 72.5% in combined metal treated cells compared to control. Activity of 17beta Hydroxy Steroid Dehydrogenase (17betaHSDH), a key steroidogenic enzyme was reduced by 52% in Cd and 37% in combined metal exposed cells whereas Pb exposed cells showed 31% reduction in the enzyme activity. Pretreatment with SH groups protectants (glutathione [GSH], dithiothretol [DTT]) and zinc caused an ameriolation in enzyme activity whereas Zn pretreatment showed an increase in gonadotropin binding in metal exposed cells. These results suggest that both Pb and Cd can cause a reduction in LH and FSH binding, which significantly alters steroid production in vitro and exerts a direct influence on granulosa cell function.

Relationship of sexuality with psychological and hormonal features in the menopausal period

Women may experience some mental and sexual problems between the ages of 40 years and 60 years due to serious changes in the hormonal system. The aim of this study was to examine the relationships between the changes in sex hormones, sexual behaviours, depression and anxiety levels of women who were in either the premenopausal, perimenopausal or postmenopausal period. The subjects of this cross-sectional study consisted of 324 women who attended the Gynaecology and Obstetrics Out-Patient Ward of Celal Bayar University Hospital. Of this group, 37.0 (n = 124) were postmenopausal, 27.2 (n = 84) perimenopausal and 35.8 (n = 116) premenopausal. Beck Depression Inventory (BDI), State and Trait Anxiety Inventories (STAI-I and II) and a questionnaire on sexual behaviour which was prepared for this study by the authors, were applied to all of the attendees and serum sex hormone levels were analyzed. Beck Depression Anxiety, STAI-I and STAI-II scores and sexual behaviours did not show any statistically significant difference among these three groups. The frequency of sexual intercourse was lower in women with high BDI scores. The rate of painful intercourse was higher in women with high STAI-I scores. The frequency of sexual intercourse, sexual desire and orgasm decreased and painful intercourse increased in women with high STAI-II scores. The frequency of sexual intercourse decreased significantly as the age or follicle stimulating hormone level of women increased. These findings have revealed that the menopausal state did not affect the sexual behaviour, and psychological state of women between the ages of 40 and 60 years, but the increase in anxiety and depression scores affected the sexual life in a negative manner

Influence of GnRH Agonist and Neural Antagonists on Stress-blockade of LH and Prolactin Surges Induced by 17 beta-estradiol in Ovariectomized Rats

In our previous study, we demonstrated that immobilization stress blocked estrogen-induced luteinizing hormone(LH) surge possibly by inhibiting the synthesis and release of gonadotropin-releasing hormone (GnRH) at the hypothalamic level and by blocking estrogen-induced prolactin (PRL) surge by increasing the synthesis of dopamine receptor at the pituitary level in ovariectomized rats. The present study was performed to determine whether immobilization stress affects pituitary LH responsiveness to GnRH, and whether endogenous opioid peptide (EOP) and dopamine systems are involved in blocking LH and PRL surges during immobilization stress. Immobilization stress was found to inhibit basal LH release and to completely abolish LH surge. However, the intravenous application of GnRH agonist completely restored immobilization-blocked LH surge and basal LH release. Treatment with naloxone did not exert any effect on immobilization-blocked LH surge but increased basal LH release during immobilization stress. Pimozide did not affect immobilization-blocked LH surge or basal LH release. Naloxone also decreased immobilization-induced basal PRL release, but had no effect on immobilization-blocked PRL surge. Immobilization-increased basal PRL levels were augmented by pimozide treatment and immobilization-blocked PRL surge was dramatically restored by pimozide. We conclude that immobilization stress does not impair pituitary LH response to GnRH, and that the immobilization stress-induced blockage of LH surge is probably not mediated by either the opioidergic or the dopaminergic system. However, immobilization-blockade of PRL surge may be partly mediated by the dopaminergic system.

Effect of leptin on LH and FSH release in ovariectomized rats

We compared the estradiol/progesterone-induced luteinizing hormone [LH] and follicle-stimulating hormone [FSH] release between normally fed and leptin-supplemented starved ovariectomized female rats and studied also the effect of hyper-leptinaemia on the steroid-induced hormonal release in normally fed ovariectomized rats. Three days' starvation completely abolished steroid-induced LH and FSH release. Significant recovery of the hormonal release was shown in the leptin-supplemented starved group. The magnitudes of LH and FSH release in the normally fed animals with a higher dose of leptin were statistically the same as those in the normally fed group without leptin. These observations indicate that physiological concentrations of circulating leptin exert a stimulatory effect on steroid-induced LH and FSH release

Hipersecreçäo do hormônio luteinizante / Hypersecretion of luteinizing hormone

O hormônio luteinizante (LH), glicoproteína estruturada em duas subunidades com 121 aminoácidos e 4 sítios de glicosilaçäo, é sintetizado pelos gonadotropos hipofisários de modo pulsátil, em resposta aos pulsos de GnRH. Na foliculogênese o LH estimula a síntese basal de progesterona pelos folículos antrais menores que 7mm e de androstenediona e testosterona, de modo crescente, nos folículos maiores. No folículo dominante, que contém agora receptores para o LH nas células da granulosa, esta gonadotrofina induz a luteinizaçäo, atenuaçäo da enzima P450 17 e a síntese de progesterona. O pico de LH no meio do ciclo reinicia e completa a primeira divisäo meiótica, inibe o inibidor da maturaçäo do oocisto e estimula a síntese de prostaglandinas e proteínas líticas responsáveis pela extrusäo física do oocisto. A hipersecreçäo do LH na fase folicular inicial afeta a maturaçäo do oocisto, acelera o consumo dos oocistos e está relacionada com baixas taxas de fertilizaçäo, esterilidade e a altas taxas de abortamentos espontâneos. Os mecanismos responsáveis pela hipersecreçäo incluem as alteraçöes na pulsatilidade, a elevaçäo precoce do inibidor da maturaçäo do oocisto, deficiência do fator atenuador do pico de LH e alteraçöes nos moduladores intragonadais da açäo do LH

Effect of naloxone on GnRH-induced LH and FSH release in buffalo, Bubalus bubalis.

The effect of naloxone on GnRH-induced LH and FSH release was measured in buffaloes in luteal phase of estrous cycle. Animals were administered intravenously, naloxone/saline (50 mg/injection) every 15 min for 3 hr followed by GnRH (100 micrograms). Peripheral plasma LH and FSH concentrations were measured in blood samples collected at 15 min intervals from 1 hr prior to beginning of naloxone/saline treatment up to 3 hr post GnRH administration and every 30 min for the subsequent 3.5 hr. Between the animals of Group I administered naloxone and those of Group II given saline, GnRH-induced peak LH and FSH concentrations, the total LH and FSH released in response to GnRH, and the time to peak LH and FSH concentrations were not significantly different. The results of the present study suggest the absence of a direct effect of naloxone on pituitary responsiveness to GnRH.

Antisense mRNA for NPY-Y1 receptor in the medial preoptic area increases prolactin secretion

We investigated the participation of neuropeptide Y-Y1 receptors within the medial preoptic area in luteinizing hormone, follicle-stimulating hormone and prolactin release. Four bilateral microinjections of sense (control) or antisense 18-base oligonucleotides of messenger ribonucleic acid (mRNA) (250 ng) corresponding to the NH2-terminus of the neuropeptide Y1 receptor were performed at 12-h intervals for two days into the medial preoptic area of ovariectomized Wistar rats (N = 16), weighing 180 to 200 g, treated with estrogen (50 µg) and progesterone (25 mg) two days before the experiments between 8.00 and 10:00 a.m. Blockade of Y1 receptor synthesis in the medial preoptic area by the antisense mRNA did not change plasma luteinizing hormone or follicle-stimulating hormone but did increase prolactin from 19.6 + or - 5.9 ng/ml in the sense group to 52.9 + or - 9.6 ng/ml in the antisense group. The plasma hormones were measured by radioimmunoassay and the values are reported as mean + or - SEM. These data suggest that endogenous neuropeptide Y in the medial preoptic area has an inhibitory action on prolactin secretion through Y1 receptors

Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro

We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 µM and 10 µM). The effect of R-PIA (10 nM) was blocked by the addition of 8-cyclopentyltheophylline (CPT), a selective A1 adenosine receptor antagonist, at the dose of 1 µM. The addition of an A2 receptor-specific agonist, 5-N-methylcarboxamidoadenosine (MECA), at the doses of 1 nM to 1 µM had no significant effect on LH or FSH secretion, suggesting the absence of this receptor subtype in the gonadotrope. However, a sharp inhibition of the basal secretion of these gonadotropins was observed after the administration of 10 µM MECA. This effect mimicked the inhibition induced by R-PIA, supporting the hypothesis of the presence of A1 receptors in the gonadotrope. R-PIA (1 nM to 1 µM) also inhibited the secretion of LH and FSH induced by phospholipase C (0.5 IU/ml) in a dose-dependent manner. These results suggest the presence of A1 receptors and the absence of A2 receptors in the gonadotrope. It is possible that the inhibition of LH and FSH secretion resulting from the activation of A1 receptors may have occurred independently of the increase in membrane phosphoinositide synthesis

A transiçäo da perimenopausa / The perimenopausal transition

Os objetivos deste artigo säo: 1- Definir idade de início e duraçäo da transiçäo da perimenopausa. 2- Descrever as alteraçöes hormonais, lipídicas e ósseas que ocorrem durante a transiçäo da perimenopausa. 3- Atentar para os principais requisitos de cuidados preventivos com a saúde no período da vida correspondente à perimenopausa.

Contribuiçäo para o estudo do comportamento da prolactina endometrial / Study endometrial prolactin secretion

Com objetivo de verificar o comportamento da prolactina endometrial, foram estudadas 40 mulheres, com média etaria de 28,3 anos e selecionadas por apresentarem os seguintes sintomas : alteraçäo do ciclo menstrual e/ou esterilidade e/ ou galactorreia. As pacientes foram distribuidas entre os seguintes grupos : Grupo G1, dez mulheres hiperprolactinemicas com menstruaçöes regulares ; G2, nove mulheres hiperprolactinemicas com menstruaçöes irregulares; Grupo G3, onze mulheres normoprolactinemicas com menstruaçöes regulares; Grupo G4, dez mulheres normoprolactinemicas com menstruaçöes irregulares. As 40 mulheres foram redistribuidas segundo o padrao endometrial nos seguintes grupos : Grupo G5, mulheres com ciclos ovulatorios e Grupo G6, mulheres com ciclos anovulatórios. Nas pacientes ovulatórias, ainda correlacionaram-se os percentuais de prolactina endometrial com fase lutea adequada e inadequada. Exames laboratoriais foram realizados na fase folicular inicial (do terceiro ao nono dia), fase lutea inicial (do 15. ao 21. dia) e fase lutea tardia ( do 22. ao 29. dia), nas pacientes que menstruavam (1,2 e 3 amostras, respectivamente) e, nas que näo menstruavam, no primeiro, 14 e 21 dia da consulta (1,2 e 3 amostras, respectivamente)...

Disfunçäo endócrina reprodutiva e as epilepsias / Reproductive endocrine dysfuction and epilepsy

Recentemente, têm sido relatadas síndromes endócrinas em mulheres epilépticas, relacionando-se estas síndromes à reduçäo da fertilidade. Em particular, a síndrome do ovário policístico é observada com maior frequência em mulheres epiléticas, em comparaçäo à populaçäo geral. Alguns fatores podem ser considerados na tentativa de explicaçäo deste fenômeno. Em primeiro lugar, é possível que a atividade epilética, através de descargas paroxísticas atingindo o hipotálamo, interfira na atividade funcional hormonal, em particular no pulso gerador do hormônio liberador da gonadotropina (GnRH). Por outro lado, alteraçöes endócrinas decorrentes de ciclos anovulatórios poderiam estar relacionadas ao desencadeamento de descargas epiléticas, talvez por açäo direta dessa concentraçäo hormonal anormalmente elevada nas estruturas límbicas. O objetivo deste trabalho é estudar, à luz da literatura disponível, a possível relaçäo entre crises epiléticas originadas no lobo temporal e síndrome de disfunçöes hormonais sexuais, em especial a síndrome do ovário policístico.

"Un nuevo parámetro para evaluar la luteinización prematura: la relación molecular preovulatoria entre las concentraciones séricas de progesterona y estradiol" / A new parameter to evaluates the premature luteinization: the preovulatory molecular ratio between serum progesterone and estradiol

El objetivo fue evaluar la relación molecular entre los niveles séricos preoperatorios de progesterona (P) y estradiol (E2) y determinar el efecto que tienen en los resultados obtenidos con fertilización in vitro. Se estudiaron 62 parejas tratadas con el procedimiento, fue establecida la tasa molecular entre P y E2 inmediatamente antes de administrar la gonadotropina coriónica humana (hCG). La concentración de P el día de la aplicación de hCG fue de 1.45 ñ 0.06 ng/mL, el valor de la relación P: E2 fue 0.63 ñ 0.03. Se observaron embarazos a partir de tasas moleculares de 0.22, no hubo gestaciones con tasa > 1.02. No presentaron luteinización prematura en relación con las que no tuvieron. En cuanto a la tasa de implantación aunque fue menor en pacientes con luteinización prematura, no hubo diferencia significativa con pacientes que no la presentaron. Se concluye que la relación mediante fertilización in vitro. En este trabajo como en otros reportes, la luteinización prematura no tuvo efecto sobre los resultados reproductivos

Lactation inhibits the potentiating effect of galanin upon the GnRH-induced LH release observed in diestrous-1 rat

Recent demonstrations of no changes in hypothalamic gonadotropin releasing hormone (GnRH) gene expression nd GnRH levels detected at the pituitary gland in diestrous and lactating rats, indicate that lactational hypogonadotropism in this species is not associated with inhibition of hypothalamic GnRH synthesis and secretion. Hypothalamic galanin potentiates GnRH effects on luteinizing hormone (LH) secretion in male and cycling rats. To explore the interaction between GnRH and galanin during lactation, we studied in vitro the effects of pulsatile stimulation with those peptides upon LH synthesis and secretion from rat pituitaries on diestrous 1 or day 10 of lactation. Hemipituitaries were separately incubated in 1 ml Dulbecco's Minimal Essential Medium supplemented with 1 per cent penicillin-streptomycin and fetal calf serum, at 37 degrees Celsius in 5 per cent CO2-air. The hemipituitaries were stimulated during 12 h with hourly pulses, 6 min each, of (a) gonadotropin releasing hormone (GnRH 25 ng/pulse), (b) rat galanin (600 ng/pulse), (c) GnRH plus galanin, or (d) saline. Medium was collected before each pulse to determine LH by radioimmunoassay. After the 12 h pulsatile regime total RNA was extracted and both actin and beta-LH mRNA were determined by reverse transcriptase polymerase chain reaction. There was a significant stimulation of LH secretion by GnRH (ANOVA, p<0.001) without significant differences between diestrous and lactation pituitaries. Galanin alone did not modify LH secretion but it potentiated the effect of GnRH upon pituitaries from diestrous (p=0.036) but not lactating rats. Neither peptide alone or its combination modified pituitary beta-LH mRNA levels. Results show that galanin regulates differently the secretion and synthesis of LH at the pituitary level. The disappearance of galanin-induced potentiation of GnRH effects upon LH secretion during lactation might contribute to the hypogonadotropism of lactation in the rat.

Endocrinologia do ovário no climatério perimenopáusico / The ovarian endocrinology in the perimenopausal period

O climatério, período de transiçäo entre o menacme e a senectude, compreende uma série de fenômenos clínicos, biológicos e endocrinológicos, que se iniciam muito antes da instalaçäo da menopausa e prosseguem por anos após a mesma. A endocrinologia de transiçäo menopáusica, compreendida nesse período, é o objetivo do presente trabalho de revisäo da literatura. Observa-se, inicialmente, diminuiçäo na secreçäo de Inibina, um polipeptídeo produzido pelas células da granulosa, responsável por modulaçäo da secreçäo de FSH. Há aumento do FSH, seguido de aumento do LH e diminuiçäo da esteroidogênese ovariana, resultando em hipoestrogenismo e diminuiçäo dos níveis de progesterona, o que concorre para a série de alteraçöes que caracterizam esse período.

Fucosylated glycoconjugates of the human spermatozoon. Comparison of the domains of these glycoconjugates with the alpha-fucosyl binding sites, and with lactosaminic glycoconjugates and beta-D-galactosyl binding site domains

Fucosylated glycoconjugates play an important role in fertilization as the recognition signal of the zona pellucida. In this work, using "critical" concentrations of either, FITC Lotus tetragonolobus lectin or FITC alpha-L-fucosyl-BSA neoglycoprotein as molecular probes, population densities of fucosylated glycoconjugates and of their "complementary" molecules (carrying fucosyl receptors), were found all over the sperm surface with higher population densities in post acrosomal sheath, neck and midpiece. These results were compared with previously reported data on the population densities of lactosaminic compounds and their "complementary" molecules, obtained on same samples of spermatozoa. Statistical data demonstrate that fucosylated glycoconjugates share the same domains with biantennary N-acetyllactosaminic oligosaccharides carrying outer galactose and bisected N-acetylglucosamine residues. These domains highly differ with those of the lactosaminic glycoproteins carrying tri and tetraantennary N-acetyllactosaminic oligosaccharides. These studies also show that the domains of fucosylated glycoconjugates and their "complementary" molecules (carrying fucosyl receptors) locate in different zones of the spermatozoon than those of the compounds carrying beta-galactosyl receptors. Besides, the results suggest structural differences between fucosylated glycoconjugates of the acrosome, equatorial zone and post acrosomal sheath. This may be relevant to the different biological behavior of these compounds and zones, in fertilization.