Abstract
The arachidonic acid metabolite 12-hydroxyeicosatetraenoic acid (12-HETE)
is assumed to play an important role in skin physiology and pathophysiology.
Specifically, it has recently been discussed as a growth promoting
agent in keratinocytes. Our aim was to find out whether epidermal
cells possess specific receptors for 12-HETE which would mediate
the effects of this eicosanoid in skin, including the putative growth
stimulating activity. We could identify specific binding sites for
12(S)-HETE on the human epidermal cell line SCL-II. The analysis
of binding data revealed a single class of binding sites with a Kd
of 2,6 nM and a Bmax of 216,000 sites per cell. The binding was saturable,
readily reversible, and specific for 12(S)-HETE with lower affinities
for other monoHETE. We failed to detect any significant proliferative
activity of 12(S)-HETE in the same epidermal cell line, although
we applied three independent methods for evaluation of cell growth
and used a concentration of 12(S)-HETE which should enable an optimal
receptor occupancy. Thus, epidermal cells possess high-affinity 12(S)-HETE
binding sites which are likely to be involved in the effects of this
eicosanoid in epidermis. However, biologic effects other than direct
growth stimulation seem to be transduced by 12(S)-HETE receptors
in epidermal cells which need further investigation.
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