Effect of graded periods of congenital hypothyroidism on the peripheral auditory evoked activity of rats.
Rats were treated with a goitrogen, propylthiouracil (PTU), from 3 days before delivery up to different ages postnatally. Peripheral auditory function was evaluated with the auditory brain-stem response (ABR) technique performed at 200 days of age. All groups of rats exposed consecutively pre- and postnatally to PTU displayed permanent auditory impairment for each stimulus modality used, as revealed by significantly prolonged wave I latencies and elevated thresholds, and the severity of these abnormalities was directly related to the duration of PTU treatment. The only congenitally hypothyroid animals not affected were those treated from 3 days before parturition up to birth and those treated for 10 days beginning at 35 days of age. These data underline the susceptibility of the developing auditory system since, while very brief perinatal PTU exposure resulted in permanent evoked response abnormalities, longer exposure in later life had no effect.
Hebert
R
R
Langlois
J M
JM
Dussault
J H
JH
D000818:Animals; D003409:Congenital Hypothyroidism; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D007037:Hypothyroidism / Q000503:physiopathology*; D011247:Pregnancy; D011441:Propylthiouracil / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D011441:Propylthiouracil