Circulating Levels of Orexin-A, Nesfatin-1, Agouti-Related Peptide, and Neuropeptide Y in Patients with Hyperthyroidism.
BACKGROUND
There is insufficient information about the appetite-related hormones orexin-A, nesfatin-1, agouti-related peptide (AgRP), and neuropeptide Y (NPY) in hyperthyroidism. The aim of the present study was to investigate the effects of hyperthyroidism on the basal metabolic rate (BMR) and energy intake, orexin-A, nesfatin-1, AgRP, NPY, and leptin levels in the circulation, and their relationship with each other and on appetite.


METHODS
In this prospective study, patients were evaluated in hyperthyroid and euthyroid states in comparison with healthy subjects. Twenty-one patients with overt hyperthyroidism and 33 healthy controls were included in the study.


RESULTS
Daily energy intake in the hyperthyroid state was found to be higher than that in the euthyroid state patient group (p=0.039). BMR was higher in hyperthyroid patients than the control group (p=0.018). Orexin-A was lower and nesfatin-1 was higher in hyperthyroid patients compared to the controls (p<0.001), whereas orexin-A increased and nesfatin-1 decreased after euthyroidism (p=0.003, p<0.001). No differences were found in the AgRP, NPY, and leptin levels between the hyperthyroid and euthyroid states and controls (p>0.05). Orexin-A correlated negatively with nesfatin-1 (p=0.042), BMR (p=0.013), free triiodothyronine (fT3; p<0.001), and free thyroxine (fT4; p<0.001) and positively with thyrotropin (TSH; p<0.001). Nesfatin-1 correlated negatively with orexin-A (p=0.042) and TSH (p<0.001) and positively with fT3 (p=0.005) and fT4 (p=0.001). In the regression analysis, "diagnosis of hyperthyroidism" was the main factor affecting orexin-A (p<0.001).


CONCLUSIONS
Although it seems that no relationship exists among orexin-A, nesfatin-1, and increased appetite in hyperthyroidism, the orexin-A and nesfatin-1 levels are markedly affected by hyperthyroidism.
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Yusuf
Y
Tohma
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Mujde
M
Akturk
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Alev
A
Altinova
2 Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey .
Emine
E
Yassibas
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Ethem Turgay
ET
Cerit
3 Department of Biochemistry, Faculty of Medicine, Gazi University , Ankara, Turkey .
Ozlem
O
Gulbahar
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Metin
M
Arslan
2 Department of Nutrition and Dietetics, Faculty of Health Sciences, Gazi University , Ankara, Turkey .
Nevin
N
Sanlier
1 Department of Endocrinology and Metabolism, Gazi University , Ankara, Turkey .
Fusun
F
Toruner
D000328:Adult; D054369:Agouti-Related Protein / Q000097:blood*; D001066:Appetite / Q000502:physiology; D001481:Basal Metabolism / Q000502:physiology; D002135:Calcium-Binding Proteins / Q000097:blood*; D016022:Case-Control Studies; D004268:DNA-Binding Proteins / Q000097:blood*; D002149:Energy Intake / Q000502:physiology; D005260:Female; D006111:Graves Disease / Q000097:blood* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000503:physiopathology / Q000628:therapy; D020738:Leptin / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000097:blood*; D009478:Neuropeptide Y / Q000097:blood*; D000080866:Nucleobindins; D000068797:Orexins / Q000097:blood*; D011446:Prospective Studies; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D055815:Young Adult
C515198:AGRP protein, human; D054369:Agouti-Related Protein; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D020738:Leptin; C000630650:NUCB2 protein, human; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D000080866:Nucleobindins; D000068797:Orexins; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine