The role of angiotensin II (AII) in human preadipocyte physiology has been
investigated in primary cultures from human adipose tissue. Receptor bindin
g studies indicated that human preadipocytes express a high affinity AII bi
nding site of the AT, subtype, as binding of I-125-labeled [Sar(1),Ile(8)]A
II was rapid, saturable, and specific. As All has previously been demonstra
ted to affect the cell cycle in adrenal and cardiac cells, the effect of AI
I on regulation of cycle progression was examined in human preadipocytes. S
timulation of preadipocytes with AII resulted in G(1) phase progression of
the cell cycle, as determined by now cytometric analysis. AII treatment was
associated with induction of expression of the messenger RNA for the cell
cycle regulatory protein cyclin D1 in a dose-dependent manner. Pretreatment
of cells with subtype-selective AT receptor ligands before AII stimulation
indicated that the cyclin response was mediated via the AT, receptor. The
identity of the cells as preadipocyte was verified by culture in a defined
differentiation medium, observing both leptin message expression and trigly
ceride accumulation by flow cytometry. These findings indicate that All has
early, receptor-mediated effects on cell cycle progression in human preadi
pocytes that may contribute to differentiation to the adipocyte phenotype.