Our previous study demonstrates that matrix metalloproteinase 2 (MMP-2) is differentially regulated by the interplay between glucose and insulin. In this context, it was intriguing to examine the regulation of the other well-studied MMPs, MMP-9, in 3T3-L1 pre-adipocytes. Our results revealed that, as the scenario in MMP-2 regulation, glucose was a pre-requisite for determining pre-adipocytes’ responses to external stimuli. Short-term and long-term insulin exposure exhibited opposite regulation to MMP-9 under high glucose-containing environment. The dominant MMP-9 regulatory role of long-term insulin under euglycemia was diminished when culture environment contained high glucose concentration. Our results suggest pre-adipocytes may participate in the process of increasing adiposity through mediating extracellular matrix alterations resulted from the changes of MMP-9 expression/activity.
Key words: insulin, glucose, obesity, pre-adipocytes, adipocytes, matrix metalloproteinase-9