title: Hypothalamo-pituitary-thyroid axis function during cardiopulmonary bypass.
abstract: Marked alterations in levels of circulating thyroid hormone were found in patients undergoing cardiopulmonary bypass with a rise in the free thyroxine and a fall in the free triiodothyronine levels. Studies using thyrotropin-releasing hormone during bypass demonstrated a blunted response to this stimulus. This reduced response is related to changes in thyroid hormone levels and it is suggested that bypass surgery may have a direct inhibitory action on thyroid-stimulating hormone release at the hypothalamo-pituitary level. The potential significance of these hormonal changes is discussed.
mesh_terms: D000328:Adult; D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000502:physiology*; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D013974:Thyroxine