1
|
Ohga H, Ohta K, Matsuyama M. Long-day stimulation increases thyroid-stimulating hormone expression and affects gonadal development in chub mackerel. Comp Biochem Physiol A Mol Integr Physiol 2023; 275:111334. [PMID: 36280226 DOI: 10.1016/j.cbpa.2022.111334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 11/19/2022]
Abstract
For seasonal breeders, photoperiodic changes are important signals that mark the start of the breeding season. Thyroid-stimulating hormone (TSH) is a glycoprotein hormone that not only promotes the secretion of thyroid hormone but also plays a key role in regulating seasonal reproduction in birds and mammals. However, whether TSH activation has been implicated as a seasonal indicator in fish breeding has not been fully investigated. In this study, we isolated tshb as a starting point to elucidate the effect of photoperiodic changes on the activation of the reproductive axis of chub mackerel. The isolated tshb was classified as tshba, which is widely conserved in vertebrates. The quantitative PCR results showed that tshb was strongly expressed in the pituitary. When female and male chub mackerel with immature gonads were reared for six weeks under different photoperiodic conditions, the gonads developed substantially in the long-day (LD) reared fish compared to those in the short-day reared fish. Real-time PCR results showed that the expression level of tshb in the pituitary gland was significantly elevated in the LD group. Although there was no difference in the gonadotropin-releasing hormone 1 gene expression level in the preoptic area of the brain, follicle-stimulating hormone and luteinizing hormone gene expression levels in the pituitary were also significantly elevated in the LD group. In conclusion, TSH is a potential mediator of seasonal information in the reproductive endocrine axis and may induce gonadal development during the breeding season of chub mackerel.
Collapse
Affiliation(s)
- Hirofumi Ohga
- Aqua-Bioresource Innovation Center (ABRIC) Karatsu Satellite, Kyushu University, Saga 847-0132, Japan.
| | - Kohei Ohta
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | | |
Collapse
|
2
|
Nyuji M, Hamaguchi M, Shimizu A, Isu S, Yoneda M, Matsuyama M. Development of sandwich enzyme-linked immunosorbent assays for chub mackerel Scomber japonicus gonadotropins and regulation of their secretion in female reproduction. Gen Comp Endocrinol 2022; 328:114103. [PMID: 35940318 DOI: 10.1016/j.ygcen.2022.114103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 07/25/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022]
Abstract
The pituitary gonadotropins (Gths), follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh), play critical roles in regulating gonadal development and sexual maturation in vertebrates. We developed non-competitive enzyme-linked immunosorbent assays (ELISAs) to measure Fsh and Lh in chub mackerel Scomber japonicus, which is a commercially important scombrid species. Mouse monoclonal antibodies specific for Fsh and Lh, and a rabbit polyclonal antibody against both Gths were produced by immunization with hormones purified from chub mackerel pituitaries. These monoclonal and polyclonal antibodies were used as capture and detection antibodies in the developed sandwich ELISAs. The ELISAs were reproducible, sensitive, and specific for chub mackerel Fsh and Lh. Parallelism between the standard curve and serial dilutions of chub mackerel serum and pituitary extract was observed for both Fsh and Lh ELISAs. Comparison between vitellogenic and immature females revealed that Fsh is secreted during vitellogenesis and Lh is barely released during immaturity. After gonadotropin-releasing hormone analog (GnRHa) injection, vitellogenic females showed increases in serum Lh, whereas serum levels of Fsh did not vary. Moreover, the serum steroid profiles revealed that estradiol-17β was continuously produced after GnRHa treatment, whereas 17,20β-dihydroxy-4-pregnen-3-one secretion was transiently induced. These results indicate that, in vitellogenic females, GnRHa stimulates the release of Lh, but not Fsh, which results in acceleration of vitellogenesis and induction of oocyte maturation via steroid production.
Collapse
Affiliation(s)
- Mitsuo Nyuji
- Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Nagasaki 851-2213, Japan.
| | - Masami Hamaguchi
- Fisheries Technology Institute, Hatsukaichi Field Station, Japan Fisheries Research and Education Agency, Hiroshima 739-0452, Japan
| | - Akio Shimizu
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Yokohama 236-8648, Japan
| | - Sayoko Isu
- Fisheries Resources Institute, Japan Fisheries Research and Education Agency, Yokohama 236-8648, Japan
| | - Michio Yoneda
- Fisheries Technology Institute, Hakatajima Field Station, Japan Fisheries Research and Education Agency, Imabari 794-2305, Japan
| | - Michiya Matsuyama
- Aqua-Bioresource Innovation Center, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| |
Collapse
|
3
|
Duan X, Jia X, Liang K, Huang F, Shan J, Chen H, Ruan X, Li L, Zhao H, Wang Q. Liposome-Encapsulated Rec8 and Dmrt1 Plasmids Induce Red-Spotted Grouper (Epinephelus akaara) Testis Maturation. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:345-353. [PMID: 35303207 DOI: 10.1007/s10126-022-10111-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
In fish, the maturity of gonads plays an important role in the development and reproduction of the population, and it also dictates the success of captive breeding. Therefore, finding ways to promote gonadal maturation is an important goal in aquaculture. In this study, we injected recombinant dmrt1 and rec8 overexpression plasmids packaged in liposomes into the immature testis of red-spotted grouper (Epinephelus akaara) and measured the expression of Dmrt1 and Rec8 protein in vivo. Gonadosomatic index (GSI) and gonadal histology analyses showed that the testis developed from the immature to the mature state within 7 days after plasmid injection. Additionally, the spermatozoa concentration and motility in plasmid-injected fish was the same as that of naturally mature fish. These results provided evidence that delivery of dmrt1 and rec8 expression plasmids into the testis via injection induced testis maturation in vivo.
Collapse
Affiliation(s)
- Xuzhuo Duan
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Xianze Jia
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Kaishan Liang
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Fengqi Huang
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Jinhong Shan
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Huitao Chen
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Xinhe Ruan
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Lihua Li
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Huihong Zhao
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region On Marine Bioresource Conservation and Exploitation, Guangzhou, 510642, China.
| | - Qing Wang
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
- University Joint Laboratory of Guangdong Province, Hong Kong and Macao Region On Marine Bioresource Conservation and Exploitation, Guangzhou, 510642, China.
| |
Collapse
|
4
|
Leptin Is an Important Endocrine Player That Directly Activates Gonadotropic Cells in Teleost Fish, Chub Mackerel. Cells 2021; 10:cells10123505. [PMID: 34944013 PMCID: PMC8700583 DOI: 10.3390/cells10123505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/26/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022] Open
Abstract
Leptin, secreted by adipocytes, directly influences the onset of puberty in mammals. Our previous study showed that leptin stimulation could promote the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary cells in primary culture and ovarian development in chub mackerel. This study aimed to elucidate the detailed mechanism of leptin-induced effects on gonadotropin hormone-producing cells. We produced recombinant leptin using silkworm pupae and investigated the effects of leptin on FSH and LH secretion and gene expression in the primary culture of pituitary cells from chub mackerel. The presence or absence of co-expression of lepr mRNA, FSH and LH b-subunit mRNA in gonadotropic cells was examined by double-labeled in situ hybridization. The addition of leptin significantly increased the secretion and gene expression of FSH and LH from male and female pituitary cells in primary culture. In contrast, gonadotropin-releasing hormone 1 affected neither FSH secretion in cells from females nor fshb and lhb expression in cells from males and females. The expression of lepr was observed in FSH- and LH-producing cells of both males and females. The results indicate that leptin directly regulates gonadotropin synthesis and secretion and plays an important role in the induction of puberty in teleost fish.
Collapse
|
5
|
Dai X, Pu D, Wang L, Cheng X, Liu X, Yin Z, Wang Z. Emergence of breeding tubercles and puberty onset in male zebrafish: evidence for a dependence on body growth. JOURNAL OF FISH BIOLOGY 2021; 99:1071-1078. [PMID: 34037242 DOI: 10.1111/jfb.14811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/31/2021] [Accepted: 05/23/2021] [Indexed: 06/12/2023]
Abstract
The presence of breeding tubercles (BTs) on the pectoral fins has been investigated as a typical male secondary sexual characteristic (SSC) that distinguish males from females in adult zebrafish. Nonetheless, the earliest occurrence of these tubercles and its association with puberty onset and body growth remain unclear. In this study, using morphological, histological and statistical analyses, the authors examined the first appearance of BTs and puberty onset in male zebrafish, with particular emphasis on the potential impact of body growth on them. The results of this study revealed that BTs distributed along the first five branched pectoral fin rays were the earliest manifestation of male SSCs, which is significantly strongly correlated with body weight (R2 = 0.9609, P < 0.001), and could be used as a "gold standard" for the earliest sex distinction (<0.1 g in weight). Using the first appearance of BTs (<0.20 mm2 ) as a metric, the authors established that male puberty commenced at a body weight of c. 0.056 ± 0.015 g or a standard length of 10.99 ± 1.051 mm (mean ± S.D.). In this study, the authors thus established a simple method that can be used to sex live zebrafish at the pubertal stage and provides the first evidence for the relationship of BTs and male puberty initiation with body growth. These findings will accordingly lay a foundation for exploring mechanisms of the SSCs and male puberty onset in zebrafish and other teleost fish.
Collapse
Affiliation(s)
- Xiangyan Dai
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Deyong Pu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Liping Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Xinkai Cheng
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Xiaoqin Liu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Zhan Yin
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhijian Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| |
Collapse
|
6
|
Ohga H, Matsuyama M. In vitro action of leptin on gonadotropin secretion in pre-pubertal male chub mackerel. Comp Biochem Physiol A Mol Integr Physiol 2020; 253:110856. [PMID: 33249145 DOI: 10.1016/j.cbpa.2020.110856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/31/2022]
Abstract
Leptin directly influences gonadotropin (GTH) secretion from female pituitary cells in vitro and is a key signal at the onset of puberty in female chub mackerel (Scomber japonicus). Here, we investigated whether leptin also influences GTH secretion in male chub mackerel. The addition of 1 nM homologous recombinant leptin to pre-pubertal male pituitary cells stimulated follicle-stimulating hormone secretion after 1 and 2 h of culture. Therefore, leptin signaling could also directly facilitate GTH secretion in male chub mackerel.
Collapse
Affiliation(s)
- Hirofumi Ohga
- Fisheries Research Institute of Karatsu, Kyushu University, Saga 847-0132, Japan.
| | - Michiya Matsuyama
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| |
Collapse
|
7
|
Ohga H, Ito K, Matsumori K, Kimura R, Ohta K, Matsuyama M. Leptin stimulates gonadotropin release and ovarian development in marine teleost chub mackerel. Gen Comp Endocrinol 2020; 292:113442. [PMID: 32084348 DOI: 10.1016/j.ygcen.2020.113442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 12/13/2022]
Abstract
Leptin transmits information about energy stored in the periphery to the reproductive axis and is an essential signal for puberty initiation in mammals; however, to date, few studies have focused on the direct effects of leptin stimulation on reproductive factors in fish. This study demonstrated the effect of leptin stimulation on important reproductive factors and ovarian development in the marine teleost chub mackerel (Scomber japonicus). We prepared recombinant leptin and conducted functional analyses through in vitro bioassays using primary pituitary cells, long-term leptin treatment administered to pre-pubertal females, and intracerebroventricular (ICV) administration. The results showed that leptin stimulation strongly induced gonadotropin (follicle-stimulating hormone: FSH and luteinizing hormone: LH) secretion from pituitary cells collected from pre-pubertal females, and that long-term leptin treatment significantly promoted ovarian development and triggered pubertal onset. Furthermore, ICV administration of leptin did not affect kisspeptin gene expression but significantly upregulated gonadotropin-releasing hormone 1 (gnrh1), fshb and lhb gene expression in sexually immature females. These results strongly suggest leptin as an important signal for reproductive-axis activation in chub mackerel.
Collapse
Affiliation(s)
- Hirofumi Ohga
- Fisheries Research Institute of Karatsu, Faculty of Agriculture, Kyushu University, Saga 847-0132, Japan.
| | - Kosuke Ito
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Kojiro Matsumori
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Ryuto Kimura
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Kohei Ohta
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| | - Michiya Matsuyama
- Laboratory of Marine Biology, Faculty of Agriculture, Kyushu University, Fukuoka 819-0395, Japan
| |
Collapse
|
8
|
Liu Y, Li S, Wang Q, Chen Y, Qi X, Liu Y, Liu X, Lin H, Zhang Y. Molecular identification of the Dyn/Kor system and its potential role in the reproductive axis of goldfish. Gen Comp Endocrinol 2018; 257:29-37. [PMID: 28242307 DOI: 10.1016/j.ygcen.2017.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 12/12/2022]
Abstract
To ascertain the significance of the dynorphin/kappa-opioid receptor (Dyn/Kor) system in fish reproduction, prodynorphin (pdyn) cDNA was cloned from goldfish. Two Dyn peptides (DynA and DynB) are present in the goldfish prodynorphin precursor. Both DynA and DynB are biologically active as they are able to functionally interact with the goldfish Kor expressed in cultured eukaryotic cells to suppress forskolin-induced CRE promoter activity. RT-PCR analysis showed that pdyn is widely expressed in brain regions, with the highest expression in hypothalamus. During ovarian development, hypothalamic pdyn and kor mRNA levels are lower in the early vitellogenic stage. Then the biological effects of Dyn peptides on salmon gonadotropin releasing hormone (sgnrh), luteinizing hormone beta (lhb) and follicle stimulating hormone beta (fshb) mRNA synthesis were further investigated in goldfish. Intraperitoneal injections of DynA and DynB significantly reduced hypothalamic sgnrh and pituitary lhb and fshb mRNA levels in male goldfish, but these two peptides only down-regulated sgnrh and lhb mRNA expression in female goldfish. In vitro studies revealed that DynA also decreased lhb mRNA levels in primary cultures of pituitary cells, indicating that this peptide can exert its actions at the pituitary level. Our findings suggest that the Dyn/Kor system plays a negative role in regulating the reproductive axis in goldfish.
Collapse
Affiliation(s)
- Yali Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Shuisheng Li
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| | - Qing Wang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yu Chen
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xin Qi
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yun Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Xiaochun Liu
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Haoran Lin
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yong Zhang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
| |
Collapse
|
9
|
Ohga H, Selvaraj S, Matsuyama M. The Roles of Kisspeptin System in the Reproductive Physiology of Fish With Special Reference to Chub Mackerel Studies as Main Axis. Front Endocrinol (Lausanne) 2018; 9:147. [PMID: 29670580 PMCID: PMC5894438 DOI: 10.3389/fendo.2018.00147] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/19/2018] [Indexed: 12/27/2022] Open
Abstract
Kisspeptin, a novel neuropeptide product of the Kiss1 gene, activates the G protein-coupled membrane receptor G protein-coupled receptor 54 (now termed Kiss1r). Over the last 15 years, the importance of the kisspeptin system has been the subject of much debate in the mammalian research field. At the heart of the debate is whether kisspeptin is an absolute upstream regulator of gonadotropin-releasing hormone secretion, as it has been proposed to be the master molecule in reproductive events and plays a special role not only during puberty but also in adulthood. The teleostean kisspeptin system was first documented in 2004. Although there have been a number of kisspeptin studies in various fish species, the role of kisspeptin in reproduction remains a subject of controversy and has not been widely recognized. There is an extensive literature on the physiological and endocrinological bases of gametogenesis in fish, largely derived from studying small, model fish species, and reports on non-model species are limited. The reason for this discrepancy is the technical difficulty inherent in developing rigorous experimental systems in many farmed fish species. We have already established methods for the full life-cycle breeding of a commercially important marine fish, the chub mackerel (cm), and are interested in understanding the reproductive function of kisspeptins from various perspectives. Based on a series of experiments clarifying the role of the brain-pituitary-gonad axis in modulating reproduction in cm, we theorize that the kisspeptin system plays an important role in the reproduction of this scombroid species. In this review article, we provide an overview of kisspeptin studies in cm, which substantially aids in elucidating the role of kisspeptins in fish reproduction.
Collapse
|
10
|
Lumayno SDP, Ohga H, Selvaraj S, Nyuji M, Yamaguchi A, Matsuyama M. Molecular characterization and functional analysis of pituitary GnRH receptor in a commercial scombroid fish, chub mackerel (Scomber japonicus). Gen Comp Endocrinol 2017; 247:143-151. [PMID: 28153577 DOI: 10.1016/j.ygcen.2017.01.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 10/20/2022]
Abstract
The gonadotropin-releasing hormone (GnRH) is essential during pubertal onset, for its regulation of the synthesis and release of pituitary gonadotropins. Its action is mediated by GnRH receptors (GnRHRs) in the pituitary gonadotrophs. Our previous study demonstrated that the chub mackerel brain expresses three GnRH forms (gnrh1, gnrh2, and gnrh3), and that only GnRH1 neurons innervate anterior pituitary regions. Furthermore, chub mackerel gnrh1 mRNA exhibited a significant increase at pubertal onset. The present study aimed to isolate the functional GnRHR form involved in chub mackerel puberty. The open reading frame of our cloned receptor encodes 428 amino acids and contains seven transmembrane domains. Phylogenetic analysis also indicated clustering with other teleost-type IIB GnRHRs, mainly those involved in reproduction. Reporter gene assay results showed that all four synthetic peptides (GnRH1, GnRH2, GnRH3, and GnRH analogue) bind to the cloned receptor. Three deduced GnRH ligands stimulated luteinizing hormone (LH) release from cultured pituitary cells in vitro. Receptor gene expression was mainly detected in the pituitary and showed an increasing trend in the developing gonadal stages of both sexes during the pubertal process; this process was synchronous with previous studies of follicle-stimulating hormone beta (fshβ) and lhβ gene expression in chub mackerel. These results suggest that the cloned receptor is likely involved in the regulation of pubertal onset in this species. Therefore, we have designated the receptor cmGnRHR1.
Collapse
Affiliation(s)
| | - Hirofumi Ohga
- Laboratory of Marine Biology, Kyushu University, Fukuoka 812-8581, Japan
| | - Sethu Selvaraj
- Laboratory of Marine Biology, Kyushu University, Fukuoka 812-8581, Japan
| | - Mitsuo Nyuji
- Laboratory of Marine Biology, Kyushu University, Fukuoka 812-8581, Japan
| | - Akihiko Yamaguchi
- Laboratory of Marine Biology, Kyushu University, Fukuoka 812-8581, Japan
| | - Michiya Matsuyama
- Laboratory of Marine Biology, Kyushu University, Fukuoka 812-8581, Japan.
| |
Collapse
|
11
|
Ohga H, Hirata D, Matsumori K, Kitano H, Nagano N, Yamaguchi A, Matsuyama M. Possible role of the leptin system in controlling puberty in the male chub mackerel, Scomber japonicus. Comp Biochem Physiol A Mol Integr Physiol 2017; 203:159-166. [DOI: 10.1016/j.cbpa.2016.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 12/25/2022]
|
12
|
Selvaraj S, Kitano H, Ohga H, Yamaguchi A, Matsuyama M. Expression changes of mRNAs encoding kisspeptins and their receptors and gonadotropin-releasing hormones during early development and gonadal sex differentiation periods in the brain of chub mackerel (Scomber japonicus). Gen Comp Endocrinol 2015; 222:20-32. [PMID: 25304825 DOI: 10.1016/j.ygcen.2014.09.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 01/15/2023]
Abstract
In recent years, brain kisspeptin system has been shown to be involved in diverse reproductive function, including sexual differentiation in vertebrates. Our previous reports demonstrated that the chub mackerel (Scomber japonicus) brain expresses two kisspeptin (kiss1, kiss2), two kisspeptin receptor (kissr1, kissr2) and three gonadotropin-releasing hormone (gnrh1, gnrh2, gnrh3) genes. In the present study, using quantitative real-time PCR (qRT-PCR) assays, we analysed expression changes of these genes during early development (0-30dphs) and gonadal sex differentiation periods (37-60dphs). Absolute expression level of kiss-kissr-gnrh in the whole head was higher between 0 and 15dphs, in comparison to later developmental periods. Histological analyses revealed presence of sexually differentiated males and females with testicular and ovarian features at 37, 45, and 60dphs. In both males and females, kiss2, kissr1, and kissr2 levels were higher at 37dph, in comparison to 45 and 60dphs, with kiss1 showing no significant differences. Levels of all three gnrh mRNAs were higher at 45dph, in comparison to 60dph. Changes in the expression level of kiss-kissr-gnrh mRNAs in different brain regions of sexually differentiated males and females indicated differences in their regional distribution. These results suggest possible involvement of Kiss-KissR-GnRH systems during early development and gonadal sex differentiation in the chub mackerel.
Collapse
Affiliation(s)
- Sethu Selvaraj
- Laboratory of Marine Biology, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Hajime Kitano
- Fisheries Research Institute of Karatsu, Department of Joint Research, Faculty of Agriculture, Kyushu University, Saga 847-0132, Japan
| | - Hirofumi Ohga
- Laboratory of Marine Biology, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Akihiko Yamaguchi
- Laboratory of Marine Biology, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan
| | - Michiya Matsuyama
- Laboratory of Marine Biology, Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
| |
Collapse
|
13
|
mRNA levels of kisspeptins, kisspeptin receptors, and GnRH1 in the brain of chub mackerel during puberty. Comp Biochem Physiol A Mol Integr Physiol 2015; 179:104-12. [DOI: 10.1016/j.cbpa.2014.09.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 08/09/2014] [Accepted: 09/15/2014] [Indexed: 11/17/2022]
|