Effects of hypo- and hyperthyroidism on noradrenergic activity and glycerol concentrations in human subcutaneous abdominal adipose tissue assessed with microdialysis.
Thyroid hormones play a major role in lipid metabolism. However, whether they directly affect lipolysis locally in the adipose tissue remains unknown. Therefore, we measured abdominal sc adipose tissue norepinephrine (NE), basal, and isoprenaline-stimulated lipolysis in 12 hypothyroid patients (HYPO), six hyperthyroid patients (HYPER), and 12 healthy controls by in vivo microdialysis. Adipose tissue NE was decreased in HYPO and increased in HYPER compared with controls (90.4 +/- 2.9 and 458.0 +/- 69.1 vs. 294.9 +/- 19.5 pmol/liter, P < 0.01). Similarly, basal lipolysis, assessed by glycerol assay, was lower in HYPO and higher in HYPER than in controls (88.2 +/- 9.9 and 566.0 +/- 42.0 vs. 214.3 +/- 5.1 micromol/liter P < 0.01). The relative magnitude of isoprenaline-induced glycerol increase was smaller in HYPO (39 +/- 19.4%, P < 0.05 vs. basal) and higher in HYPER (277 +/- 30.4%, P < 0.01) than in controls (117 +/- 5.6%, P < 0.01). The corresponding changes in NE after isoprenaline stimulation were as follows: 120 +/- 9.2% (P < 0.05), 503 +/- 113% (P < 0.01), and 267 +/- 17.2 (P < 0.01). In summary, by affecting local NE levels and adrenergic postreceptor signaling, thyroid hormones may influence the lipolysis rate in the abdominal sc adipose tissue.
Haluzik
Martin
M
Third Department of Medicine, First Faculty of Medicine, Prague, Czech Republic.
Nedvidkova
Jara
J
Bartak
Vladimir
V
Dostalova
Ivana
I
Vlcek
Petr
P
Racek
Pavel
P
Taus
Michal
M
Svacina
Stepan
S
Alesci
Salvatore
S
Pacak
Karel
K
D000005:Abdomen; D000273:Adipose Tissue / Q000378:metabolism*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005990:Glycerol / Q000378:metabolism*; D006801:Humans; D006980:Hyperthyroidism / Q000378:metabolism*; D007037:Hypothyroidism / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008066:Lipolysis; D017551:Microdialysis; D008875:Middle Aged; D009638:Norepinephrine / Q000378:metabolism*; D009994:Osmolar Concentration; D040521:Subcutaneous Tissue / Q000378:metabolism
D000318:Adrenergic beta-Agonists; D007545:Isoproterenol; D005990:Glycerol; D009638:Norepinephrine