Influence of estradiol-17β, testosterone, and 11-ketotestosterone on testicular development, serum steroid hormone, and gonadotropin secretion in male red sea bream Pagrus major

ABSTRACT:   In order to investigate the influence of estrogen and androgen on reproductive activities of male teleosts, male red sea bream were implanted with silicone capsules containing estradiol-17β (E2), testosterone (T) or 11-ketotestosterone (11-KT) in immature and early spermatogenic stages. One month after implantation of either E2 or T, the gonadosomatic index decreased in accordance with testicular regression in both stages. Implantation of E2 decreased circulating 11-KT levels but did not affect gonadotropin (GTH) subunits, follicle stimulating hormone-β (FSHβ), luteinizing hormone-β (LHβ), α glycoprotein subunit (αGSU) gene expression, and serum LH levels in both stages. Alternatively, T decreased serum 11-KT and LH levels, and FSHβ and LHβ mRNA levels in the early spermatogenic stage but not in the immature stage. These results suggest E2 may directly inhibit testicular development through the suppression of 11-KT production. Meanwhile, T may decrease serum 11-KT levels through the suppression of FSH and LH secretion, resulting to inhibition of testicular development in the early spermatogenic stage. Treatment with 11-KT did not affect the testis in either stage, whereas 11-KT increased LHβ and αGSU mRNA levels in immature, and decreased FSHβ mRNA levels in the early spermatogenic stage. These results suggest that 11-KT may have different effects on GTH subunit gene expression in each reproductive stage.     

Effects of dietary testosterone on growth and sex ratio in juvenile Atlantic salmon (Salmo salar)

Diets to which testosterone (1 or 10 ng/g diet) had been added were fed to juvenile Atlantic salmon (Salmo salar) for nine months beginning for months after hatching (Experiment 1) and upon completion of yolk absorption (Experiment 2) to determine the effects on growth, gonadal development, and sex ratio. Dietary testosterone at 10 ng/g fed to juvenile salmon at four months after hatching (Exp. 1) induced significant changes in condition factor (0.69±0.01) compared to controls (0.79±0.01) at the end of the test period. In both experiments, salmon treated with 10 ng/g diet induced a significantly higher percentage of male fish compared to controls. Dietary testosterone at 1 ng/g fed to juvenile salmon beginning four months after hatching induced significant increases in weight (18.95±0.99) and length (13.58±0.23) compared to controls (14.55±1.50 and 11.94±0.43, respectively). In Experiment 1 or 2, there was no apparent influence of dietary testosterone on precocious male sexual development. Dietary testosterone at 1 or 10 ng/g fed to juvenile salmon upon completion of yolk absorption (Exp. 2) induced no consistent changes in growth in juvenile Atlantic salmon. These studies indicate that low levels of dietary testosterone may influence physiological responses in juvenile Atlantic salmon dependent upon timing of treatment.     

Effects of the aromatase inhibitor Fadrozole on plasma sex steroid secretion and oocyte maturation in female coho salmon (Oncorhynchus kisutch) during vitellogenesis

17-estradiol, 17-20-dihydroxy-4-pregnen-3-one (17-20-P), and testosterone levels were measured in plasma samples obtained from vitellogenic coho salmon (Oncorhynchus kisutch) before and 32 days after injection of the aromatase inhibitor Fadrozole (AI). Plasma 17-estradiol levels decreased significantly 6 h after injection in all AI treated fish. The higher the dose the longer the maintenance of low plasma 17-estradiol levels. Inversely, plasma 17-20-P increased significantly 6 h after injection in all AI treated fish, and the higher the dose the longer the maintenance of high plasma 17-20-P levels. At 48 h after injection plasma testosterone levels were significantly higher in the AI treated groups. The oocyte maturation index showed that multiple injections with AI retarded oocyte development. Besides, oocyte diameter and GSI were lower in the same group, which presented high incidence of atresia of vitellogenic oocytes. The ovarian follicles and brain of the fish which received multiple injections secreted less 17-estradiol, in vitro. These findings suggest that aromatase inhibitors such as Fadrozole may have a potential as a tool to regulate sexual development in salmon.     

Influence of gonadotropic hormone-releasing hormone analog (GnRH-A) on plasma sex steroid profiles and milt production in male winter flounder,Pseudopleuronectes americanus (Walbaum)

The effects of gonadotropic hormone-releasing hormone analog (GnRH-A) treatment on the onset and duration of increases in plasma sex steroids and milt production (milt volume and number of spermatozoa) were investigated in prespawning male winter flounder. After treatment of maturing males during the winter with a single injection of either 20 or 200 g/kg [D-Ala⁶, Pro⁹-NHEt]LHRH (GnRH-A), plasma levels of testosterone and 11-ketotestosterone were increased within 12h and the steroid hormone levels remained elevated for long periods lasting several days. The androgenic steroid response of males was delayed after the administration of a lower dose of GnRH-A (2 g/kg). Although a single GnRH-A injection in December or January advanced the onset of spermiation in some males, only small amounts (<50 l) of milt could be collected. By March, all males were in spermiating condition following GnRH-A treatment; however, significant increases in sperm production, particularly increases in milt volume, occurred in fish twice treated with GnRH-A.Part of this work presented at the First Symposium of Fish Endocrinology, Edmonton, Alberta, Canada June 1988 and the Satellite Symposium on Applications of Comparative Endocrinology to Fish Culture, Almuñecar, Granada, Spain May 1989     

大豆黄酮对肉鸡生长的影响及其作用机制研究

日粮中添加３ｇ／ｔ大豆黄酮，对８７只３２日龄红布罗肉鸡进行了２８天生长对比试验。结果表明：与对照组比较，实验组公肉鸡日增重提高１０．１％（Ｐ＜０．０１），胸肌重和腿肌重分别提高６．５％（Ｐ＜０．０５）和７．２％（Ｐ＜０．０５），胸肌总ＲＮＡ含量显著提高，但总ＤＮＡ含量无显著变化；血清尿酸水平也下降１４．２％（Ｐ＜０．０５）。提示大豆黄酮促进公肉鸡肌细胞肥大肌肉蛋白质沉积。同时大豆黄酮显著提高公肉鸡血清睾酮含量；但对母肉鸡日增重和雌二醇水平无显著影响。     

Dual adenovirus and distemper virus pneumonia in a dog

Summary

A case of simultaneous infection of the lungs of a dog with canine distemper virus (CDV) and canine adenovirus (CA V) is described. The techniques employed are histological stains, immunoperoxidase technique, and transmission electron microscopy. Two viruses are shown to infect the same cells.

The significance of dual infection of the same cells is discussed in comparison with literature data on in vitro experiments.     

睾酮水平的变化对老年男性躯体健康和精神健康的影响

目的 分析睾酮水平的变化对老年男性躯体健康和精神健康的影响。方法 选取2012年1月至2015年12月于重庆市垫江县人民医院体检的符合纳入标准的302例男性作为研究对象。分别检测睾酮水平,进行问卷调查,评估躯体健康和精神健康与睾酮水平变化的关系。结果 随着年龄的增长,睾酮水平逐渐下降,3组两两比较差异有统计学意义（P<0.05）;躯体健康、精神健康的轻度风险、中度风险、重度风险组之间,睾酮水平两两比较差异有统计学意义（P<0.05）。结论 重庆市垫江县老年男性血清睾酮水平可能随年龄增长而下降,睾酮水平的下降影响着老年男性的躯体健康和精神健康。     

Effect of three natural phytochemicals supplementation on growth performance,testosterone level and feed utilization of Nile tilapia (Oreochromis niloticus)

An 84‐day feeding experiment was conducted to determine the effects of dietary ginseng extract (GE), tribulus extract (TE) and date palm pollen grains (DPPG) on growth, testosterone level and nutrient utilization of Nile tilapia, Oreochromis niloticus, fingerlings. Seven experimental treatments were conducted in three replicates: control fed basal diets without any supplementations, GE_0.2 (supplemented with 0.2 g GE/kg diet), GE_0.4 (supplemented with 0.4 g GE/kg diet), TE_0.6 (supplemented with 0.6 g TE/kg diet), TE_1.2 (supplemented with 1.2 g TE/kg diet), DPPG₃ (supplemented with 3 g DPPG/kg diet) and DPPG₆ (supplemented with 6 g DPPG/kg diet). The results indicated that all dietary phytochemicals significantly increased growth compared to the control. Plasma testosterone levels were improved by 86.27%, 64.58%, 57.35% and 24.58% with TE_1.2, GE_0.4, TE_0.6 and DPPG₆, respectively, more than the control. The relationship between testosterone and final body weight showed a significant simple linear regression with a positive correlation. The nutrient utilization imprxoved with higher doses of phytochemical supplementations. Moreover, protein content increased and ether extract decreased with phytochemical supplementation. The present results concluded that higher doses of GE, TE and DPPG could be used as growth promoters and testosterone boosters for Nile tilapia fingerlings.     

睾丸酮丛毛单胞菌3α-HSD的研究进展

3α-HSD(3α-hydroxysteroid dehydrogenase)是睾丸酮丛毛单胞菌在以类固醇为唯一碳源时,产生的一种类固醇脱氢酶,也是降解类固醇的关键酶。本文对睾丸酮丛毛单胞菌3α-HSD基因的调控、酶蛋白结构与功能等生物学特点进行阐述,总结了3α-HSD蛋白的两种获得途径:天然提取和人工诱导表达途径。从技术可行性、实用性和成本控制等几个方面,分析比对二者的优势和不足。介绍和展望了睾丸酮丛毛单胞菌3α-HSD在血清总胆汁酸测定、转基因生物工程、环境或食品中类固醇类激素检测及环境修复等领域的研究现状和应用前景。