YC-1-like potentiation of nitric oxide-dependent activation of soluble guanylate cyclase by adrenochrome

The influence of adrenochrome and YC-1 activation of human platelet soluble guanylate cyclase was investigated. Adrenochrome (0.1-10.0 μM) had no effect on the basal activity, but it potentiated in a concentration-dependent manner the spermine NONO-induced activation of this enzyme. Adrenochrome also sensitized guanylate towards nitric oxide (NO) and produced the leftward shift of the spermine NONO concentration response curve. Addition of adrenochrome decreased the YC-1-induced leftward shift of the spermine NONO concentration response curve. Adrenochrome also inhibited enzyme activation byYC-1. Thus, synergistic activation of NO-stimulated guanylate cyclase activity by adrenochrome represents a new biochemical effect of this compound and indicates that adrenochrome may act as an endogenous regulator of the NO-dependent stimulation of soluble guanylate cyclase. This new property of adrenochrome, similar to YC-1 but more effective, should be taken into consideration especially under conditions of adrenochrome overproduction in the body. © Pleiades Publishing, Ltd. 2009.