New data from University of Michigan, Department of Human Genetics illuminate research in hormones
2007 NOV 20 -- New research, 'Dietary thyroid hormone replacement ameliorates hearing deficits in hypothyroid mice,' is the subject of a report. "Thyroid hormone (TH) insufficiency causes variable hearing impairment and mental deficiency in humans. Rodents lacking TH have congenital hearing deficiency that has been attributed to physiologic, morphologic, and developmental abnormalities of the auditory system," scientists in the United States report. "We examined four genetically defined strains of hypothyroid mice for development of hearing and response to TH replacement initiated during late gestation and continued through six weeks of age. Auditory brain stem response studies showed variable hearing impairment in homozygous mutants of each strain at three weeks of age relative to normal littermates. Mutants from three of the strains still had hearing deficiencies at six weeks of age. TH-enriched diet significantly improved hearing in three-week-old mutants of each strain relative to untreated mutants. Differences in the level of hearing impairment between the Prop1df and Pit1dw mutants, which have defects in the same developmental pathway, were determined to be due to genetic background modifier genes. Further physiologic and morphologic studies in the Cgatm1Sac strain indicated that poor hearing was due to cochlear defects," wrote I.J. Karolyi and colleagues, University of Michigan, Department of Human Genetics. The researchers concluded: "We conclude that TH supplement administered during the critical period of hearing development in mice can prevent deafness associated with congenital hypothyroidism of heterogeneous genetic etiology." Karolyi and colleagues published their study in Mammalian Genome (Dietary thyroid hormone replacement ameliorates hearing deficits in hypothyroid mice. Mammalian Genome, 2007;18(8):596-608). For more information, contact I.J. Karolyi, University of Michigan Medical School, Dept. of Human Genetics, Ann Arbor, Michigan 48109-0618 USA.. Publisher contact information for the journal Mammalian Genome is: Springer, 233 Spring Street, New York, NY 10013, USA. Keywords: United States, Ann Arbor, Hormones. This article was prepared by Life Science Weekly editors from staff and other reports. Copyright 2007, Life Science Weekly via NewsRx.com.
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