Effect of dietary administration of letrozole and tamoxifen on gonadal development, sex differentiation and biochemical changes in common carp (Cyprinus carpio L.)

2015 ◽  
Vol 27 (3) ◽  
pp. 449 ◽  
Author(s):  
Atul K. Singh ◽  
P. P. Srivastava ◽  
Rita Verma ◽  
Sharad C. Srivastava ◽  
Dinesh Kumar ◽  
...  

The effect of letrozole and tamoxifen on the specific growth rate (SGR; % day–1), gonado–somatic index (GSI), total haemoglobin (g%), gonadal and serum protein as well as lipid, sex differentiation and 17β-oestradiol levels were studied in sexually undifferentiated Cyprinus carpio fingerlings 30 days post fertilisation (30 dpf) for 60 days. Results showed decreased GSI with tamoxifen treatment whereas letrozole increased it. There were reduced protein, lipid, triglyceride and cholesterol levels after treatment with tamoxifen and letrozole during gonadal development. Tamoxifen (200 mg kg–1 feed) induced 82.5% masculinisation, whereas letrozole in the same dose produced 98.5% males. Gonadal 17β-oestradiol significantly declined from 86.0 ± 1.41 pg per 100 mg (control) to 45.5 ± 1.94 pg per 100 mg with tamoxifen and 36.0 ± 0.72 pg per 100 mg with letrozole treatment. Similarly, serum 17β-oestradiol levels also decreased after tamoxifen and letrozole treatments. Testicular development in 37.8% of fish treated with tamoxifen and letrozole was found to be more advanced (spermatocytes) than in the control (spermatogonium); however, there was reduced ovarian growth and increased atresia. It was concluded that letrozole and tamoxifen both significantly affect sex differentiation and gonadal maturity in C. carpio leading to the production of sex-reversed males, yet the effect of letrozole was more potent.

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 941
Author(s):  
Xuan Liu ◽  
Xianyi Xie ◽  
Hongling Liu

Environmental estrogen is a substance that functions as an endocrine hormone in organisms and can cause endocrine system disruption. A typical environmental estrogen, diethylstilbestrol (DES), can affect normal sexual function and organism development. However, even though the effects of different exposure stages of DES on the endocrine system and gonadal development of zebrafish juveniles are unknown, sex determination is strongly influenced by endocrine-disrupting chemicals (EDCs). From 10–90 days post fertilization (dpf), juvenile zebrafish were exposed to DES (100 and 1000 ng/L) in three different stages (initial development stage (IDS), 10–25 dpf; gonadal differentiation stage (GDS), 25–45 dpf and gonadal maturity stage (GMS), 45–60 dpf). Compared with that of IDS and GMS, the growth indicators (body length, body weight, and others) decreased significantly at GDS, and the proportion of zebrafish females exposed to 100 ng/L DES was significantly higher (by 59.65%) than that of the control; in addition, the zebrafish were biased towards female differentiation. The GDS is a critical period for sex differentiation. Our results show that exposure to environmental estrogen during the critical gonadal differentiation period not only affects the development of zebrafish, but also affects the population development.


Reproduction ◽  
2000 ◽  
pp. 327-330 ◽  
Author(s):  
RJ Lucas ◽  
JA Stirland ◽  
YN Mohammad ◽  
AS Loudon

The role of the circadian clock in the reproductive development of Syrian hamsters (Mesocricetus auratus was examined in wild type and circadian tau mutant hamsters reared from birth to 26 weeks of age under constant dim red light. Testis diameter and body weights were determined at weekly intervals in male hamsters from 4 weeks of age. In both genotypes, testicular development, subsequent regression and recrudescence exhibited a similar time course. The age at which animals displayed reproductive photosensitivity, as exhibited by testicular regression, was unrelated to circadian genotype (mean +/- SEM: 54 +/- 3 days for wild type and 59 +/- 5 days for tau mutants). In contrast, our studies revealed a significant impact of the mutation on somatic growth, such that tau mutants weighed 18% less than wild types at the end of the experiment. Our study reveals that the juvenile onset of reproductive photoperiodism in Syrian hamsters is not timed by the circadian system.


PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168874 ◽  
Author(s):  
Feibiao Song ◽  
Lanmei Wang ◽  
Wenbin Zhu ◽  
Jianjun Fu ◽  
Juanjuan Dong ◽  
...  

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2665-2675 ◽  
Author(s):  
R.S. Viger ◽  
C. Mertineit ◽  
J.M. Trasler ◽  
M. Nemer

Mammalian gonadal development and sexual differentiation are complex processes that require the coordinated expression of a specific set of genes in a strict spatiotemporal manner. Although some of these genes have been identified, the molecular pathways, including transcription factors, that are critical for the early events of lineage commitment and sexual dimorphism, remain poorly understood. GATA-4, a member of the GATA family of transcription factors, is present in the gonads and may be a regulator of gonadal gene expression. We have analyzed the ontogeny of gonadal GATA-4 expression by immunohistochemistry. GATA-4 protein was detected as early as embryonic day 11.5 in the primitive gonads of both XX and XY mouse embryos. In both sexes, GATA-4 specifically marked the developing somatic cell lineages (Sertoli in testis and granulosa in ovary) but not primordial germ cells. Interestingly, abundant GATA-4 expression was maintained in Sertoli cells throughout embryonic development but was markedly down-regulated shortly after the histological differentiation of the ovary on embryonic day 13.5. This pattern of expression suggested that GATA-4 might be involved in early gonadal development and possibly sexual dimorphism. Consistent with this hypothesis, we found that the Mullerian inhibiting substance promoter which harbors a conserved GATA element is a downstream target for GATA-4. Thus, transcription factor GATA-4 may be a new factor in the cascade of regulators that control gonadal development and sex differentiation in mammals.


2017 ◽  
Vol 38 (4Supl1) ◽  
pp. 2551
Author(s):  
Juliana Stephany de Souza ◽  
Maria Carolina Villani Miguel ◽  
Marcos Antônio Maioli ◽  
Arthur Nelson Trali Neto ◽  
David Giraldo Arana ◽  
...  

The study of gonadal development improves the understanding of factors that can influence the reproductive development process. This study aims to characterize bovine fetal testicular development and the testosterone level in the Nellore breed. For the study, 162 bovine fetuses aged between 3 and 8 months were collected from Nellore cows at a local abattoir. The fetal age was estimated by DP=8.4+0.087L+5.46?L, where DP is the estimated pregnancy day and L represents fetal length. The fetal gonadal weight (g), width (cm), and thickness (cm) were measured. Thereafter, the gonads were submitted to classic histology processes in 3-µm-thick slices cut at 210 µm intervals. The Sertoli cells, Leydig cells, and germ cells were counted. Blood samples were collected from umbilical cords for testosterone levels. The data were analyzed using the Spearman correlation test followed by Principal Component Analysis and one-way ANOVA to compare the averages between months. The testicular weight and volume were found to have a positive correlation with the numbers of Sertoli cells (r = 0.84; p < 0.0001 and r = 0.92; p < 0.0001, respectively), Leydig cells (r = 0.80; p < 0.0001 and r = 0.90; p < 0.0001, respectively), and germ cells (r = 0.84; p < 0.0001 and r = 0.93; p < 0.0001, respectively) and to be negatively correlated with testosterone plasmatic concentration (r = -0.31; p = 0.0001 and r = -0.22; p = 0.006, respectively) during pregnancy. After the fifth month, the numbers of Sertoli cells, Leydig cells and germ cells differed (p < 0.0001) from the following gestational months. The highest testosterone concentration (p = 0.007) was observed in the fifth month of gestation and was followed by a concentration decrease in the seventh and eighth months. The increase in cell quantity was responsible for the increase in testicular weight and volume during fetal development. On the other hand, the testosterone concentration followed the increase in testicular weight and volume until the 7th month of gestation and regressed during the 8th and 9th months, in addition to the increase in cell number.


1995 ◽  
Vol 46 (4) ◽  
pp. 723 ◽  
Author(s):  
GJ Gooley ◽  
TA Anderson ◽  
P Appleford

The gonadal development of Murray cod, Maccullochella peelii peelii, in Lake Charlegrark, Victoria, and adjacent farm ponds was evaluated. Gonadosomatic index, macroscopic classification and histological analysis were used to determine the age at first maturity and the gonadal development in this introduced population. There is a marked difference between the sexes in the size at first maturity, with females maturing at approximately 6 years of age and 2000 g in weight and males maturing at 3-4 years and 700 g. Gonadosomatic index data indicate that spawning occurs around November. Ovarian development in this species follows a pattern similar to that in a number of other teleosts. Testes have a lobular structure. Macroscopic evaluation of ovaries provided a good indication of the stage of the development of the gonad. However, the presence of spermatozoa throughout the year in the gonads of mature male fish makes the macroscopic evaluation of testicular development less reliable. Three cod, approximately 1% of the population, contained gonads with both ovarian and testicular tissue.


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