EXPRESSION OF THE 2 ISOFORMS OF PROSTAGLANDIN ENDOPEROXIDE SYNTHASE (PGHS-1 AND PGHS-2) DURING ADIPOSE CELL-DIFFERENTIATION

Expression of mRNAs encoding the two prostaglandin endoperoxide syntha se (PGHS) isoenzymes (PGHS-1 and -2) was investigated in differentiati ng clonal Ob1771 mouse preadipocytes and in mouse adipose tissues. Nor thern analysis revealed that the expression level of PGHS-1 mRNA was r educed by 98 +/- 0.2% (P< 0.01) during differentiation of Ob1771 cells , whereas PGHS-2 mRNA was not detected. By reverse transcriptase-polym erase chain reaction analysis, however, both PGHS-1 and -2 mRNA was de tected in Ob1771 preadipose cells. In addition, mRNAs encoding both is oforms were markedly expressed in primary adipose precursor cells with considerably lower expression levels in mature adipocytes (56-75% red uction, P < 0.01). Furthermore, exposure to dexamethasone (10 nM) for both 24 h (explants of adipose tissue) and 48 h (Ob1771 adipose cells) resulted in enhanced expression of PGHS-1 mRNA, whereas expression of PGHS-2 mRNA in explants of adipose tissue (24 h incubation) was reduc ed by 83 +/- 9%, (P < 0.05). In contrast, exposure to angiotensin II ( 100 nM) enhanced expression of PGHS-1 mRNA both in mature adipocytes ( 4 h incubation) and explants of adipose tissue (24 h incubation), and elevated PGHS-2 mRNA expression in mature adipocytes (4 h incubation). In conclusion, this report suggests a differential expression of PGHS mRNAs during adipose cell differentiation, and further suggests that the machinery for prostaglandin synthesis in mature adipocytes may be induced by various hormones. (C) 1997 Elsevier Science Ireland Ltd.