Seasonal changes in hepatic progesterone receptor mRNA, estrogen receptor mRNA, and vitellogenin mRNA in the painted turtle, Chrysemys picta

Custodia-Lora, Noemı́; Callard, İan P.

doi:10.1016/s0016-6480(02)00500-2

Cited by 17 publications

(8 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous studies (Giannoukos and Callard,'95) demonstrated seasonal changes in hepatic PRA and PRB during the seasonal cycle of the female turtle, with PRA being relatively constant and PRB increasing in association with follicular development and high estradiol levels (Callard et al,'78). In the present study, PRB mRNA, from which both PRA and PRB isoforms are derived (Conneely et al, '87;Custodia and Callard, 2002), is increased by estradiol treatment, as are both PRA and PRB isoforms. In an earlier study on the turtle oviduct (Reese and Callard,'89), we observed that PRB, but not PRA, was up-regulated by estradiol, suggesting tissue specific regulation.…”

Section: Discussionsupporting

confidence: 50%

“…Northern blotting was performed as previously described (Custodia-Lora and Callard, 2002), using 20 mg of total RNA from each animal from all experimental groups. Briefly, RNA samples were run on a denaturing formaldehyde gel, followed by capillary transfer into a nitrocellulose membrane and hybridization with the following probes: turtle PR cDNA, ER cDNA (Custodia-Lora and Callard, 2002), vtg cDNA probe (CharnockJones et al,'95), and turtle rRNA 18S cDNA probe (as internal standard).…”

Section: Northern Blot Analysismentioning

confidence: 99%

“…Briefly, RNA samples were run on a denaturing formaldehyde gel, followed by capillary transfer into a nitrocellulose membrane and hybridization with the following probes: turtle PR cDNA, ER cDNA (Custodia-Lora and Callard, 2002), vtg cDNA probe (CharnockJones et al,'95), and turtle rRNA 18S cDNA probe (as internal standard). The intensity of the signal was quantified using a phosphorimaging system (Bio-Rad Molecular Imager), and all data were normalized using 18S signal values.…”

Section: Northern Blot Analysismentioning

confidence: 99%

See 2 more Smart Citations

Effect of gonadal steroids on progesterone receptor, estrogen receptor, and vitellogenin expression in male turtles (Chrysemys picta)

2003

View full text Add to dashboard Cite

Hepatic vitellogenin (vtg) is a yolk precursor protein sequestered in follicular oocytes as nutrient supply for developing embryos in nonmammalian vertebrates. In prior research studies we have demonstrated that both progesterone (P) and testosterone (T) inhibit estrogen (E)-induced vitellogenesis in the male fresh water turtle (Chrysemys picta), and have suggested that these hormones may be involved in multihormonal regulation of vitellogenesis in the female turtle. However, the modes of action of progesterone and testosterone on estrogen-induced vitellogenesis are not known. We have proposed that progesterone inhibits vitellogenesis by modulation of progesterone receptor A (PRA) or B (PRB) isoforms and/or estrogen receptor (ER) gene transcription. In this study, we compare the vitellogenic responses of reproductively inactive male turtles to estradiol 17b in the presence of exogenous testosterone or progesterone. Northern blot analysis was used to monitor the changes in vtg mRNA, ER mRNA, and PR mRNA expression; Western blotting to determine changes in PR isoform expression and a homologous ELISA for measurement of plasma vtg. Progesterone and testosterone reduced estrogen-induced vtg mRNA expression, but plasma vtg was not significantly reduced by these steroids. PRA and PRB were transcribed even though ER mRNA could not be detected, suggesting constitutive PR expression. However, in the presence of estradiol 17b, both PR isoforms and mRNA transcripts were increased as a correlate of ER mRNA transcription, suggesting both transcriptional and translational effects; these effects were inhibited by testosterone and progesterone treatments. Since ER mRNA was sharply reduced by both testosterone and progesterone, and estradiol 17b increased PR mRNA transcription and translation, it is likely that the action of progesterone in reducing vtg mRNA is indirect via down regulation of ER mRNA, thus ER. This study provides further information on the role of progesterone and testosterone in the regulation of hepatic vitellogenesis, suggesting regulation of vitellogenesis mainly via modulation of hepatic ER mRNA.

show abstract

Section: Discussionsupporting

confidence: 50%

Section: Northern Blot Analysismentioning

confidence: 99%

Section: Northern Blot Analysismentioning

confidence: 99%

See 1 more Smart Citation

Effect of gonadal steroids on progesterone receptor, estrogen receptor, and vitellogenin expression in male turtles (Chrysemys picta)

2003

View full text Add to dashboard Cite

show abstract

“…In turtles, northern blotting was established in order to detect the mRNA expression of VTG [5,[7][8][9][10], but this method is not frequently performed because the usage of radioisotopes and large amounts of RNA extracts are needed. Multiple examination is not available for northern blotting.…”

Section: Discussionmentioning

confidence: 99%

“…There are numerous reports concerning the mRNA expression of VTG which investigate the effects of estrogens through reverse transcriptionpolymerase chain reaction (RT-PCR) in birds [25], zebrafish [22], so-iuy mullet [1], and marine mussel [28]. In turtles, however, only northern blotting analysis has been developed [5,[7][8][9][10].…”

mentioning

confidence: 99%

Vitellogenin, a Biomarker for Environmental Estrogenic Pollution, of Reeves' Pond Turtles: Analysis of Similarity for its Amino Acid Sequence and Cognate mRNA Expression after Exposure to Estrogen

Tada

Nakao

Hoshi

et al. 2008

The Journal of Veterinary Medical Science

View full text Add to dashboard Cite

ABSTRACT. Vitellogenin (VTG), a biomarker for environmental estrogenic pollution, can be detected in the bloodstream of oviparous animals before morphological and functional abnormalities appear due to exposure to environmental estrogens. Reports observing VTG in turtles have been limited. We therefore cloned and sequenced a partial cDNA of VTG in Reeves' pond turtle, Chinemys reevesii. The cloned cDNA fragment possessed the start codon and 2,229 bp, encoding 743 amino acid residues. A sequence of deduced amino acid from the cDNA did not contain a high serine content, such as that which exists in phosvitin. Two N-glycosylation sites were found in the sequence. The sequence was compared to those of two birds (chicken and herring gull), one amphibian (Xenopus), and five fishes (carp, zebrafish, eel, haddock, and red seabream). The C. reevesii VTG was similar to that of herring gull (78%, value of positives), chicken (76%), Xenopus (69%), eel (63%), red seabream (62%), haddock (62%), carp (62%), and zebrafish (61%). The phylogenetic tree showed that C. reevesii VTG existed between the amphibian and birds, and it was present far from fish VTGs. A reverse transcription-polymerase chain reaction method was employed to detect the mRNA expression of the C. reevesii VTG through the use of primers designed from our sequence. The VTG mRNA expression (292 bp) was proven in the total RNA extraction from the liver of the juvenile turtles which were treated with estradiol-17β. The information herein would be useful for ecotoxicological studies using freshwater turtles and these findings are expected to contribute positively towards wildlife conservation.

show abstract

Reproductive Endocrine Disruption in a Sentinel Species (Chrysemys picta) on Cape Cod, Massachusetts

Rie

Kitana

Lendas

et al. 2005

Arch Environ Contam Toxicol

View full text Add to dashboard Cite

Freshwater turtles (Chrysemys picta) were collected from two sites on Cape Cod, MA. One site (Moody Pond), adjacent to the Massachusetts Military Reservation (MMR), was considered potentially impacted by toxic agents deriving from contaminant point sources on the MMR. The second (reference) site (Washburn Pond), to the east of the MMR, was considered not impacted by these pollutants and was chosen as a control site. Plasma estradiol 17 beta and vitellogenin were significantly lower in female turtles from Moody Pond. Ovarian follicular analysis indicated a significant decrease in the >16.00-mm follicular cohort in Moody Pond female turtles compared with Washburn Pond animals. Although testicular weight was lower at the Moody Pond site, histology, plasma testosterone, and sperm number were similar to these parameters in Washburn Pond animals. The data suggest that in Moody Pond, the reproductive capacity of turtles may be negatively affected by contaminants from the MMR.

show abstract

Seasonal changes in hepatic progesterone receptor mRNA, estrogen receptor mRNA, and vitellogenin mRNA in the painted turtle, Chrysemys picta

Cited by 17 publications

References 54 publications

Effect of gonadal steroids on progesterone receptor, estrogen receptor, and vitellogenin expression in male turtles (Chrysemys picta)

Effect of gonadal steroids on progesterone receptor, estrogen receptor, and vitellogenin expression in male turtles (Chrysemys picta)

Vitellogenin, a Biomarker for Environmental Estrogenic Pollution, of Reeves' Pond Turtles: Analysis of Similarity for its Amino Acid Sequence and Cognate mRNA Expression after Exposure to Estrogen

Reproductive Endocrine Disruption in a Sentinel Species (Chrysemys picta) on Cape Cod, Massachusetts

Contact Info

Product

Resources

About