| The estrogenic and antiandrogenic pesticide methoxychlor alters the reproductive tract and behavior without affecting pituitary size or LH and prolactin secretion in male rats. | |
| | |
MedLine Citation:
|
PMID: 10188190 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
This study was designed to determine if long-term exposure to high doses of methoxychlor (M) would alter pituitary or testicular endocrine functions in either an estrogenic or antiandrogenic manner. Weanling male Long-Evans hooded rats were dosed daily with M (po) at 0, 200, 300, or 400 mg kg-1 day-1 for 10 months. Methoxychlor treatment delayed puberty by as much as 10 weeks and reduced fertility and copulatory plug formation in a dose-related manner at the initial mating. During mating, M-treated males exhibited shorter latencies to mount and ejaculate versus control males, but the number of intromissions prior to ejaculation was unaffected, indicating that M enhanced the arousal level in the males in an estrogen-dependent manner. Most treated males eventually mated but time-to-pregnancy was lengthened. Very low sperm counts were associated with infertility, while prolonged delays in puberty reduced fecundity. Methoxychlor treatment with 200 to 400 mg kg-1 day-1 failed to mimic the chronic effects of a sustained (8 months) low dose of estradiol-17 beta (3-mm silastic implants) on pituitary or testicular hormone levels. Estradiol administration increased pituitary weight 4-fold, serum levels of luteinizing hormone (LH) were reduced by almost 50%, and serum prolactin was increased 40-fold, while M did not affect any of these measures. These data demonstrate that M affects the CNS, epididymal sperm numbers, and the accessory sex glands and delays mating without significantly affecting the secretion of LH, prolactin, or testosterone. These data indicate that M did not alter pituitary endocrine function in either an estrogenic or antiandrogenic manner. To our knowledge, these data provide the first in vivo example of such a pronounced degree of target tissue selectivity to an environmental endocrine-disrupting chemical. |
| | |
Authors:
|
L E Gray; J Ostby; R L Cooper; W R Kelce |
Publication Detail:
|
Type: Journal Article |
Journal Detail:
|
Title: Toxicology and industrial health Volume: 15 ISSN: 0748-2337 ISO Abbreviation: Toxicol Ind Health Publication Date: 1999 Jan-Mar |
Date Detail:
|
Created Date: 1999-05-25 Completed Date: 1999-05-25 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 8602702 Medline TA: Toxicol Ind Health Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 37-47 Citation Subset: IM |
Affiliation:
|
Endocrinology Branch, United States Environmental Protection Agency, Research Triangle Park, NC 27111, USA. gray.earl@epamail.epa.gov |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Dose-Response Relationship, Drug Insecticides / pharmacology, toxicity* Luteinizing Hormone / drug effects, secretion* Male Methoxychlor / pharmacology, toxicity* Pituitary Gland / anatomy & histology, drug effects, physiology Prolactin / drug effects, secretion* Rats Rats, Inbred Strains Sexual Behavior, Animal / drug effects* Sperm Count / drug effects Testis / drug effects*, physiology Xenobiotics / pharmacology, toxicity |
| Chemical | |
Reg. No./Substance:
|
0/Insecticides; 0/Xenobiotics; 72-43-5/Methoxychlor; 9002-62-4/Prolactin; 9002-67-9/Luteinizing Hormone |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Neuroendocrine and reproductive effects of contemporary-use pesticides.
Next Document: Environmental antiandrogens: low doses of the fungicide vinclozolin alter sexual differentiation of ...