The atrial natriuretic peptide- and catecholamine-induced lipolysis and expression of related genes in adipose tissue in hypothyroid and hyperthyroid patients
Abstract
Thyroid dysfunction is associated with several abnormalities in intermediary metabolism including impairment of lipolytic response to catecholamines in subcutaneous abdominal adipose tissue (SCAAT). Atrial natriuretic peptide (ANP) is a powerful lipolytic peptide, however, the role of ANP-mediated lipolysis in thyroid disease has not been elucidated.
The aim of this study was to investigate the role of thyroid hormones in the regulation of ANPinduced lipolysis as well as in the gene expression of HSL (hormone sensitive lipase), PDE3B (phosphodiesterase 3B), UCP2 (uncoupling protein 2), NPR-A (natriuretic peptide receptor type A) and _2AR (_2-adrenergic receptor) in SCAAT of hyperthyroid and hypothyroid patients. Gene expression in SCAAT was studied in 13 hypothyroid and 11 hyperthyroid age matched women before and 2-4 months after the normalisation of their thyroid status.
A microdialysis study was performed on a subset of 9 hyperthyroid and 10 hypothyroid subjects. ANP- and isoprenalineinduced lipolyses were higher in hyperthyroid subjects, with no differences between the groups following treatment.
HSL gene expression was higher in hyperthyroid compared to hypothyroid subjects before treatment, while no difference was observed following treatment. No differences in gene expression of other genes were observed between the two groups.
Following treatment, the gene expression of UCP2 decreased in hyperthyroid while the expression of PDE3B decreased in hypothyroid subjects. Conclusion: Thyroid hormones regulate ANP- and isoprenaline-mediated lipolysis in human SCAAT in vivo at a post-receptor level