Thiourea-induced thyroid hormone depletion impairs testicular recrudescence in the air-breathing catfish, Clarias gariepinus

Swapna, I.; Rajasekhar, M.; Supriya, A.; Kavarthapu, Raghuveer; Sreenivasulu, G.; Rasheeda, M. K.; Majumdar, K. C.; Kagawa, Hirohiko; Tanaka, Hideki; Dutta-Gupta, Aparna; Senthilkumaran, B.

doi:10.1016/j.cbpa.2006.01.017

Cited by 79 publications

(45 citation statements)

References 38 publications

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“…In the present study, we quantified multiple dmrt1s at different phases of testicular cycle of catfish. Our real-time PCR data showed that dmrt1a and b was expressed abundantly during preparatory and pre-spawning phases where spermatogonia and spermatocytes are dominant (Swapna et al 2006), when compared with other phases of catfish testicular cycle. This indicates that in catfish, expression of dmrt1 is higher during the period of spermatogenesis and its expression decreases gradually thereafter during spawning/spermiation and postspawning phases.…”

Section: Discussionmentioning

confidence: 75%

“…This indicates that dmrt1 transcripts are abundantly expressed during active spermatogenesis i.e. in preparatory and pre-spawning phases where spermatogonia and spermatocytes are more in number (Swapna et al 2006). In addition, dmrt1a transcript is abundantly expressed in testis when compared with dmrt1b and dmrt1c transcripts.…”

Section: Dmrt1 Expression In Different Phases Of Testicular Cyclementioning

confidence: 97%

“…Commonly referred to as the African or air-breathing catfish, this species is abundantly available in the ponds and lakes of Hyderabad. The seasonal reproductive cycle of catfish is divided into four phases (Swapna et al 2006): preparatory (February-March), prespawning (April-June), spawning (July-October) and post-spawning/regressed phases (November-January). Adult gonads during the reproductive cycle of catfish were collected and a part of it was fixed in Bouin's fixative while remaining tissue was stored at K80 8C for total RNA extraction.…”

Section: Animals and Samplingmentioning

confidence: 99%

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Identification of multiple dmrt1s in catfish: localization, dimorphic expression pattern, changes during testicular cycle and after methyltestosterone treatment

Kavarthapu

Senthilkumaran²

2009

Journal of Molecular Endocrinology

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The double sex and mab-3 related (DM) transcription factor 1 (dmrt1) plays an important role in testicular differentiation. Here, we report cloning of multiple dmrt1s, a full-length and two alternative spliced forms from adult catfish (Clarias gariepinus) testis, which encode predicted proteins of 287 (dmrt1a), 253 (dmrt1b) and 233 (dmrt1c) amino acid residues respectively. Interestingly, dmrt1c lacks the majority of the DM domain. Multiple dmrt1s (dmrt1a and dmrt1c) were obtained from Clarias batrachus as well. Tissue distribution (transcript and protein) of catfish dmrt1 revealed exclusive expression in testis. Semi-quantitative RT-PCR revealed the presence of multiple dmrt1s with high levels of dmrt1a in adult testis but not in ovary. Real-time RT-PCR analysis during testicular cycle showed higher levels of dmrt1 transcripts in preparatory and pre-spawning when compared with spawning and post-spawning phases. Immunocytochemical and immunofluorescence localization revealed the presence of catfish Dmrt1 protein in spermatogonia and spermatocytes, which indicates plausible role in spermatogenesis. Histological analysis indicated initiation of gonadal sex differentiation in catfish around 40-50 days after hatching. The potential role for dmrt1 in testicular differentiation is evident from its stage-dependent elevated expression in developing testis. Furthermore, dimorphic expressions of dmrt1s were evident at different stages of gonadal development or recrudescence in catfish. Treatment of methyl testosterone (MT) during early stages of gonadal sex differentiation resulted in adult males. Interestingly, we also obtained MT-treated fishes having ova-testis gonads. Analysis of dmrt1, sox9a, foxl2 and cyp19a1 expression patterns in MT-treated gonads revealed tissue-specific pattern. These results together suggest that multiple dmrt1s are testis-specific markers in catfish.

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Section: Discussionmentioning

confidence: 75%

Section: Dmrt1 Expression In Different Phases Of Testicular Cyclementioning

confidence: 97%

Section: Animals and Samplingmentioning

confidence: 99%

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Identification of multiple dmrt1s in catfish: localization, dimorphic expression pattern, changes during testicular cycle and after methyltestosterone treatment

Kavarthapu

Senthilkumaran²

2009

Journal of Molecular Endocrinology

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“…Although less well understood, comparable effects of hypothyroidism on testicular function appear to occur in teleosts (Swapna & Senthilkumaran 2007). In the catfish Clarias gariepinus, exogenous T 4 reduced plasma and testis testosterone levels and led to fewer spermatids and spermatozoa ( Jacob et al 2005), while 21-day thiourea exposures to pre-spawning males led to narrowed seminiferous tubules and fewer spermatozoa (Swapna et al 2006). Hypothyroidism during early life has also been shown in teleosts to result in larger mass testis, more Sertoli cells, and increased spermatozoa after maturation (Matta et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Thyroid hormone regulation of mRNAs encoding thyrotropin β-subunit, glycoprotein α-subunit, and thyroid hormone receptors α and β in brain, pituitary gland, liver, and gonads of an adult teleost, Pimephales promelas

Lema¹,

Dickey²,

Schultz³

et al. 2009

Journal of Endocrinology

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Thyroid hormone regulation of mRNAs encoding thyrotropin b-subunit, glycoprotein a-subunit, and thyroid hormone receptors a and b in brain, pituitary gland, liver, and gonads of an adult teleost, Pimephales promelas AbstractThyroid hormones (THs) regulate growth, morphological development, and migratory behaviors in teleost fish, yet little is known about the transcriptional dynamics of gene targets for THs in these taxa. Here, we characterized TH regulation of mRNAs encoding thyrotropin subunits and thyroid hormone receptors (TRs) in an adult teleost fish model, the fathead minnow (Pimephales promelas). Breeding pairs of adult minnows were fed diets containing 3,5, 3 0 -triiodo-L-thyronine (T 3 ) or the goitrogen methimazole for 10 days. In males and females, dietary intake of exogenous T 3 elevated circulating total T 3 , while methimazole depressed plasma levels of total thyroxine (T 4 ). In both sexes, this methimazole-induced reduction in T 4 led to elevated mRNA abundance for thyrotropin b-subunit (tshb) in the pituitary gland. Fish treated with T 3 had elevated transcript levels for TR isoforms a and b (tra and trb) in the liver and brain, but reduced levels of brain mRNA for the immediate-early gene basic transcription factor-binding protein (bteb). In the ovary and testis, exogenous T 3 elevated gene transcripts for tshb, glycoprotein hormone a-subunit ( gpha), and trb, while not affecting tra levels. Taken together, these results demonstrate negative feedback of T 4 on pituitary tshb, identify tra and trb as T 3 -autoinduced genes in the brain and liver, and provide new evidence that tshb, gpha, and trb are THs regulated in the gonad of teleosts. Adult teleost models are increasingly used to evaluate the endocrine-disrupting effects of chemical contaminants, and our results provide a systemic assessment of TH-responsive genes during that life stage.

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“…This indicates that sox9a transcripts are abundantly expressed during active spermatogenesis, i.e. in preparatory and pre-spawning phases, wherein spermatogonia and spermatocytes (SC) are more in number (Swapna et al 2006), while sox9b transcript was abundantly expressed during preparatory phase, and later its expression was drastically reduced in prespawning, spawning, and post-spawning phases of the ovarian cycle (Fig. 4B).…”

Section: Expression Of Sox9 In Different Phases Of Testicular and Ovamentioning

confidence: 96%

Isolation of sox9 duplicates in catfish: localization, differential expression pattern during gonadal development and recrudescence, and hCG-induced up-regulation of sox9 in testicular slices

Kavarthapu¹,

Senthilkumaran²

2010

Reproduction

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In vertebrates, sox9 is a transcription factor that plays a crucial role in testicular development and chondrogenesis. Here, we report cloning of isoforms of sox9 (sox9a and sox9b) from air-breathing catfish Clarias gariepinus, which undergoes an annual reproductive cycle. Tissue distribution pattern showed differential expression of sox9 duplicates, wherein both forms were highly expressed in brain and gonads. Furthermore, we observed a dimorphic expression pattern of sox9a and sox9b in both adult and developing gonads using RT-PCR, indicating that sox9a retained its function in testis while sox9b might have a new role to play in ovary. Changes in sox9 mRNA levels using real-time quantitative PCR (qRT-PCR) during the seasonal reproductive cycle revealed that sox9a transcript in testis was abundant during testicular recrudescence (during spermatogenesis), and its expression significantly decreased during spawning and post-spawning phases. Furthermore, treatments of human chorionic gonadotropin and 11-ketotestosterone in vitro up-regulated sox9a mRNA levels in the testicular slices at 12 and 24 h time points, suggesting that gonadotropins might stimulate sox9 expression. These results suggest that sox9 might have a plausible role in the entrainment of the testicular cycle. In contrast, during the ovarian cycle, sox9b mRNA levels gradually declined from preparatory to post-spawning phases. Immunohistochemical (IHC) data showed that, in testis, sox9 is detectable in Sertoli and spermatogonial cell types except spermatid/spermatozoa. In the ovary, it is localized in the ooplasm of primary and pre-vitellogenic oocytes. These results were further confirmed by whole-mount IHC and qRT-PCR.

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Thiourea-induced thyroid hormone depletion impairs testicular recrudescence in the air-breathing catfish, Clarias gariepinus

Cited by 79 publications

References 38 publications

Identification of multiple dmrt1s in catfish: localization, dimorphic expression pattern, changes during testicular cycle and after methyltestosterone treatment

Identification of multiple dmrt1s in catfish: localization, dimorphic expression pattern, changes during testicular cycle and after methyltestosterone treatment

Thyroid hormone regulation of mRNAs encoding thyrotropin β-subunit, glycoprotein α-subunit, and thyroid hormone receptors α and β in brain, pituitary gland, liver, and gonads of an adult teleost, Pimephales promelas

Isolation of sox9 duplicates in catfish: localization, differential expression pattern during gonadal development and recrudescence, and hCG-induced up-regulation of sox9 in testicular slices

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