title: Neonatal thyroid function and anaesthesia.
abstract: Thyroid function in the neonate and its response to hexobarbitone anaesthesia were studied in newborn Wistar rats between 24 h and 42 days old. 14C-labelled mixed with unlabelled hexobarbitone was injected i.p. in anaesthetic concentrations. Serum T3, reverse T3 (rT3) and T4 and serum and whole brain hexobarbitone concentrations were measured on wakening. A decrease in serum T3 and rT3 and an increase in T4 concentrations were observed after hexobarbitone at 21 and 30 days. This appears to be a critical period in the neonatal rat. A significant negative correlation was found between the changes in serum thyroid hormone concentrations and whole-brain concentrations of hexobarbitone in 30-day-old male rats. It is suggested that similar effects may occur in the human fetus or neonate subjected to anaesthesia.
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D005260:Female; D006591:Hexobarbital / Q000378:metabolism; D008297:Male; D051381:Rats; D013961:Thyroid Gland / Q000502:physiology*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000097:blood
chemical_list: D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D006591:Hexobarbital; D013974:Thyroxine