Summary
The role of arachidonic acid oxygenated products in human platelet aggregation induced
by the ionophore A23187 was investigated. The ionophore produced an increased release
of both saturated and unsaturated fatty acids and a concomitant increased formation
of TxA2 and other arachidonate products. TxA2 (and possibly other cyclo oxygenase products) appears to have a significant role
in ionophore-induced aggregation only when low concentrations (<1 μM) of the ionophore
are employed.
Testosterone added to rat or human platelet-rich plasma (PRP) was shown previously
to potentiate platelet aggregation induced by ADP, adrenaline, collagen and arachidonic
acid (1, 2). We show that testosterone also potentiates ionophore induced aggregation
in washed platelets and in PRP. This potentiation was dose and time dependent and
resulted from increased lipolysis and concomitant generation of TxA2 and other prostaglandin products. The testosterone potentiating effect was abolished
by preincubation of the platelets with indomethacin.
Keywords
Arachidonic acid - Platelets - Ionophore A23187 - Testosterone
