Altered sex hormone concentrations and gonadal mRNA expression levels of activin signaling factors in hatchling alligators from a contaminated Florida lake

Brandon C. Moore, Satomi Kohno, Robert W. Cook, Ashley L. Alvers, Heather J. Hamlin, Teresa K Woodruff, Louis J. Guillette

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Activins and estrogens participate in regulating the breakdown of ovarian germ cell nests and follicle assembly in mammals. In 1994, our group reported elevated frequencies of abnormal, multioocytic ovarian follicles in 6 month old, environmental contaminant-exposed female alligators after gonadotropin challenge. Here, we investigated if maternal contribution of endocrine disrupting contaminants to the egg subsequently alters estrogen/inhibin/activin signaling in hatchling female offspring, putatively predisposing an increased frequency of multioocytic follicle formation. We quantified basal and exogenous gonadotropin-stimulated concentrations of circulating plasma steroid hormones and ovarian activin signaling factor mRNA abundance in hatchling alligators from the same contaminated (Lake Apopka) and reference (Lake Woodruff) Florida lakes, as examined in 1994. Basal circulating plasma estradiol and testosterone concentrations were greater in alligators from the contaminated environment, whereas activin/ inhibin bA subunit and follistatin mRNA abundances were lower than values measured in ovaries from reference lake animals. Challenged, contaminant-exposed animals showed a more robust increase in plasma estradiol concentration following an acute follicle stimulating hormone (FSH) challenge compared with reference site alligators. Aromatase and follistatin mRNA levels increased in response to an extended FSH challenge in the reference site animals, but not in the contaminant-exposed animals. In hatchling alligators, ovarian follicles have not yet formed; therefore, these endocrine differences are likely to affect subsequent ovarian development, including ovarian follicle assembly.

Original languageEnglish (US)
Pages (from-to)218-230
Number of pages13
JournalJournal of Experimental Zoology Part A: Ecological Genetics and Physiology
Volume313 A
Issue number4
DOIs
StatePublished - Apr 1 2010

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Animal Science and Zoology
  • Molecular Biology
  • Genetics

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