Regulation of metallothionein gene expression and secretion in rat adipocytes differentiated from preadipocytes in primary culture

Citation
P. Trayhurn et al., Regulation of metallothionein gene expression and secretion in rat adipocytes differentiated from preadipocytes in primary culture, HORMONE MET, 32(11-12), 2000, pp. 542-547
Citations number
30
Categorie Soggetti
Endocrinology, Nutrition & Metabolism
Journal title
HORMONE AND METABOLIC RESEARCH
ISSN journal
00185043 → ACNP
Volume
32
Issue
11-12
Year of publication
2000
Pages
542 - 547
Database
ISI
SICI code
0018-5043(200011/12)32:11-12<542:ROMGEA>2.0.ZU;2-U
Abstract
The gene encoding metallothionein, a low mel. wt. metal binding and stress response protein, is expressed in white adipose tissue. In the present stud y, metallothionein (MT-1) gene expression and factors regulating metallothi onein production have been examined in adipocytes induced to differentiate from fibroblastic preadipocytes in primary cell culture. On the induction o f differentiation, the metallothionein-1 gene was strongly expressed in the cells and metallothionein released into the medium. A peak in metallothion ein-1 mRNA level and metallothionein secretion occurred at 2 and 10 days po st-differentiation, respectively, with a decrease in protein release after this time. The metallothionein-1 gene was expressed in the adipocytes prior to the adipsin and lipoprotein lipase genes, suggesting that it is an earl y marker of adipocyte differentiation. The addition of the glucocorticoid. dexamethasone, led to a substantial increase in metallothionein-1 mRNA in t he cells and metallothionein secretion. Insulin and leptin also stimulated metallothionein production, although the effect was small. Neither noradren aline nor the beta3-adrenoceptor agonist, BRL 37 344, altered metallothione in release but forskolin and bromo-cAMP were stimulatory, markedly increasi ng both metallothionein-1 level and metallothionein secretion. It is sugges ted that metallothionein is a novel secretory product of the differentiated white adipocyte and that its production is regulated particularly by gluco corticoids and through a cAMP-dependent pathway.