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| Registros recuperados: 11 | |
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| RECABARREN,SERGIO E; LOBOS,ALEJANDRO; TORRES,VERÓNICA; OYARZO,ROBERTO; SIR-PETERMANN,TERESA. |
| Leptin, the product of the ob gene, has been proposed as a metabolic signal that regulates the secretion of GnRH/LH. This may be critical during prepubertal development to synchronize information about energy stores and the secretion of GnRH/LH. This study aimed to assess the effect of food restriction on the episodic secretion of leptin and LH in young female sheep. Five 20-week-old prepubertal females were fed a low-level diet for 10 weeks to maintain the body weight. Control females of the same age received food ad libitum. Blood samples were collected at 10-min intervals for six hours at 20, 26, and 30 weeks of age, and plasma leptin, LH, insulin and cortisol concentrations were measured. In the control group, no changes were found in pulsatile LH... |
| Tipo: Journal article |
Palavras-chave: Female sheep; Food restriction; Leptin; LH; Puberty. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000300003 |
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| Silva,Antonio E. D. Feliciano; Unanian,Maria M.; Silva,Alzira Roza e. |
| O estudo foi desenvolvido em 79 bovinos machos da raça Nelore, PO, de dez a 16 meses de idade. Em todos os animais foram medidas a circunferência escrotal (CE), a concentração de testosterona (Testo) e o aparecimento dos primeiros espermatozoides no ejaculado. Os resultados indicaram que 18,5 % dos machos em estudo apresentaram os primeiros espermatozoides aos 306,17± 2,42 dias de idade, 19,75± 0,9 cm de circunferência escrotal, e uma concentração de testosterona de 1,57± 0,9 ng/ml. Após o aparecimento dos primeiros espermatozoides no ejaculado, os machos mostraram a puberdade aos 365,39± 1,13 dias e a maturidade aos 487,38± 3,08 dias. Estes resultados indicam que existem machos na raça Nelore, PO que iniciam a atividade sexual em idades inferiores às... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Age of first spermatozoa; Scrotal circumference; Puberty; Bovine; Nelore breed. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131999000400016 |
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| Fučić,A.; Stojkovic,R.; Katić,J.; Markovic,D.; Ferencic,Z.; Koršić,M.; Jazbec,A.M.; Gamulin,M.. |
| Environmental xenoestrogens pose a significant health risk for all living organisms. There is growing evidence concerning the different susceptibility to xenoestrogens of developing and adult organisms, but little is known about their genotoxicity in pre-pubertal mammals. In the present study, we developed an animal model to test the sex- and age-specific genotoxicity of the synthetic estrogen diethylstilbestrol (DES) on the reticulocytes of 3-week-old pre-pubertal and 12-week-old adult BALB/CJ mice using the in vivo micronucleus (MN) assay. DES was administered intraperitoneally at doses of 0.05, 0.5, and 5 µg/kg for 3 days and animals were sampled 48, 72 and 96 h, and 2 weeks after exposure. Five animals were analyzed for each dose, sex, and age group.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diethylstilbestrol; Estrogen; Puberty; In vivo micronucleus assay; Sex; Genotoxicity. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100015 |
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| Latronico,A.C.; Costa,E.M.F.; Domenice,S.; Correa,R.V.; Kohek,M.B.F.; Arnhold,I.J.P.; Mendonca,B.B.. |
| Several genes that influence the development and function of the hypothalamic-pituitary-gonadal-axis (HPG) have been identified. These genes encode an array of transcription factors, matrix proteins, hormones, receptors, and enzymes that are expressed at multiple levels of the HPG. We report the experience of a single Endocrinology Unit in the identification and characterization of naturally occurring mutations in families affected by HPG disorders, including forms of precocious puberty, hypogonadism and abnormal sexual development due to impaired gonadotropin function. Eight distinct genes implicated in HPG function were studied: KAL, SF1, DAX1, GnRH, GnRHR, FSHß, FSHR, and LHR. Most mutations identified in our cohort are described for the first time in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hypogonadism; Puberty; Gonadotropins; Genetic mutation. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000100019 |
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| Zemunik,T.; Peruzovic,M.; Capkun,V.; Zekan,L.; Tomic,S.; Milkovic,K.. |
| Ten Fisher rats 50 to 55 days of age made up the pubertal group, and ten rats 90 to 95 days of age served as the controls. The testicular and epididymal weights and volumes of the pubertal males were lower than those of the controls (P<0.001). There was also a difference in relative epididymal weight (P<0.001). The sperm of pubertal males was morphologically abnormal in 58.2% of cases, as opposed to only 3.8% in the controls (P<0.001). The mean number of spermatozoa in the control group was 11.9 × 10(6)/ml and their viability was 99.6%, while these values could not be determined for pubertal rats. Serum testosterone was higher in the pubertal animals than in the controls (2.52 ± 1.46 vs 0.92 ± 0.34 nM, P<0.01). The ovaries of control females... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Puberty; Reproduction; Gonads; Sex hormones; Pregnancy. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000700007 |
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| Dai,Xin; Zhou,Ling-Yu; Xu,Ting-Ting; Wang,Qiu-Yue; Luo,Bin; Li,Yan-Yu; Gu,Chen; Li,Shi-Ping; Wang,Ai-Qin; Wei,Wan-Hong; Yang,Sheng-Mei. |
| ABSTRACT Tannins are polyphenols that are present in various plants, and potentially contain antioxidant properties that promote reproduction in animals. This study investigated how tannic acid (TA) affects the reproductive parameters of male Brandt’s voles, Lasiopodomys brandtii (Radde, 1861). Specifically, the anti-oxidative level of serum, autophagy in the testis, and reproductive physiology were assessed in males treated with TA from the pubertal stage. Compared to the control, low dose TA enhanced relative testis and epididymis weight and sperm concentration in the epididymis, and significantly increased the level of serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). mRNA levels of autophagy related genes LC3 and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antioxidative; Autophagy; Puberty; Reproduction. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702020000100319 |
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| Souza,Fernando Andrade; Martins,Jorge André Matias; Vale Filho,Vicente Ribeiro do; Andrade,Venício José de; Ferreira,Marcos Brandão Dias; Emerick,Lucas Luz; Pinto,Pablo Fabricio Bruno; Leite,Ticiano Guimarães. |
| In order to determine the profile of leptin and insulin values in seminal plasma and their correlations with sperm patterns during the peripuberty, a total of 16 crossbred Gyr dairy bulls were monitored from 60 days before to 60 days after puberty, separated into two groups, early and regular, according to the onset of puberty. Hormone values were determined by radioimmunoassay after gel filtration in fast performance liquid chromatography and semen patterns, according to the Brazilian College of Animal Reproduction. Insulin concentrations in seminal plasma did not differ between groups, nor between the ages, with the pooling of the data showing average of 35.15±16.93, 36.60±26.21, 26.82±09.81, and 43.56±31.71 32.24±16.71 U/mL for the pubertal period of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Gyr dairy bulls; Puberty; Sperm defect. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982012000400013 |
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| Meirelles,C.F.; Abdalla,A.L.; Vitti,D.M.S.S.. |
| Most Brazilian dairy production is conducted by small holders whose general management skills and feeding programs are often deficient. One common problem directly attributed to underfeeding is that heifers rarely reach sexual maturity before 15 months of age. Groups of growing heifers were treated to detect the effects of protein supplementation and antihelmintic treatment on sexual maturity. The first ovulation occurred at 513 ± 44 and 573 ± 36 days (P<.01) in supplemented and control groups, respectively. Liveweight gains from start of the trial to the first ovulation were 378 ±.02 and 331 ±.04 g for suplemented (S) and control (C) groups. Only 52.17 % of heifers in C group (11 of 23) but 95.65 % in S group (22 of 23) reached sexual maturity before... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heifers; Puberty; Protein supplementation; Antihelmintic. |
| Ano: 1994 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90161994000200026 |
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| Registros recuperados: 11 | |
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