Fasting-induced changes in thyroid hormone economy in normal and acromegalic subjects.
To study whether high growth hormone (GH) milieu may counteract fasting-induced changes in thyroid hormone economy, we measured basal and TRH-stimulated TSH concentrations as well as thyroxine (total, TT4 and free, FT4), total triiodothyronine (TT3) and total reverse T3 (TrT3) before and after a 6-day fast in 6 healthy men and in 8 patients with acromegaly. Baseline values for all parameters were similar in both groups. Fasting induced similar increases in TT4 and TrT3 concentrations and a similar decline in TT3 concentrations in both groups. The TT3/TT4 and TrT3/TT4 ratios changed identically in both groups. We conclude that high GH is incapable of altering fasting-induced changes in thyroid hormone economy.
Ho
P J
PJ
Division of Endocrinology and Metabolism, University of Michigan, Ann Arbor.
Friberg
R D
RD
Barkan
A
A
D000172:Acromegaly / Q000097:blood*; D005215:Fasting / Q000097:blood*; D013006:Growth Hormone / Q000502:physiology; D006801:Humans; D008297:Male; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000097:blood
D013963:Thyroid Hormones; D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D013006:Growth Hormone; D013974:Thyroxine