title: Thyroxine replacement in an animal model of congenital hypothyroidism.
abstract: This study examined the effects of thyroxine (T(4)) treatment on spatial learning and memory in congenitally hypothyroid (CH) rats. Forty CH male offspring of methimazole-treated dams were randomly divided into three groups: no T(4) (vehicle) treatment (n=12), T(4) treatment commencing on postnatal day (P-) 7 (n=14), and T(4) treatment commencing on P-21 (n=14). Normal male rats were used as a control group (n=14). T(4) was administered daily (sc, 0.02 microg/g) to the treatment groups for 30 days. A water-maze was used to assess behaviour at 42, 70 and 98 days of age. T(4) treatment beginning at P-7 improved learning and memory associated with CH at 70 and 98 days of age but T(4) treatment beginning at P-21 did not improve CH-impaired learning and memory.
authors: School of Psychology, University of Ulster at Jordanstown, Newtownabbey, Northern Ireland.
authors: Rosemary E
authors: RE
authors: Reid
authors: Eun-Mee
authors: EM
authors: Kim
authors: Deaglan
authors: D
authors: Page
authors: Shane M
authors: SM
authors: O'Mara
authors: Eugene
authors: E
authors: O'Hare
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D003409:Congenital Hypothyroidism / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D003423:Critical Period, Psychological; D004193:Discrimination Learning / Q000502:physiology; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D005260:Female; D020249:Hormone Replacement Therapy; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008713:Methimazole; D011247:Pregnancy; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013028:Space Perception / Q000502:physiology; D013963:Thyroid Hormones / Q000008:administration & dosage / Q000502:physiology; D013974:Thyroxine / Q000502:physiology / Q000627:therapeutic use*
chemical_list: D013963:Thyroid Hormones; D008713:Methimazole; D013974:Thyroxine