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Purpose: Endocrine-disrupting chemicals interfere with the endocrine system and therefore afect growth and pubertal progression. The study aim was to compare the growth and pubertal progression in wild-type female rats with different bedding types. Methods: Twenty 5-week-old female wild-type Sprague Dawley rats were randomly assigned to two groups with different bedding types: one group received wood shaving bedding, while a second group received corncob bedding. We determined crown-rump length and body weight as anthropometric measurements and assessed the serum growth hormone (GH) and estradiol levels. The gh1 mRNA expression levels were compared using quantitative real time transcription polymerase chain reaction. The estrous cycle was evaluated by vaginal smear. Results: The anthropometric measurements were not significantly different between the two groups. The mean relative expression of the gh1 gene was lower in the corncob bedding group than that in the wood shaving group (P=0.768). Meanwhile serum GH and estradiol were increased in the wood shaving bedding group; however this difference was not statistically significant. The time to first estrus and the length of the estrous cycle were increased in the corncob bedding group; the proportion of normal estrous cycles was also decreased. These indings indicate irregularities in the estrous cycle. Conclusion: Endocrine-disrupting chemicals in corncob bedding might be associated with time to irst estrus and length of the estrous cycle. Therefore, the type of bedding should be considered as a factor afecting pubertal progression in rodents. [ABSTRACT FROM AUTHOR]

PurposeThere were a lot of reports regarding associations of polymorphisms in the estrogen receptor α (ESR1). with many disorders. But, those with constitutional delay of growth and puberty (CDGP) are not known. Our aim is to find out any association between CDGP and ESR1.MethodsIn a total of 27 subjects, we compared 7 CDGP patients with 20 healthy controls with their heights and sexual maturity rates were within normal range. We selected three single nucleotide polymorphisms from intron 1 of ESR1 (rs3778609, rs12665044, and rs827421) as candidates, respectively.ResultsIn genotype analyses, the frequency of G/G genotype at rs827421 in intron 1 of ESR1 was increased in CDGP boys (P=0.03).ConclusionThe genetic variation of ESR1 can be a contributing factor of tempo of growth and puberty.