Early increase of cyclic adenosine monophosphate level induced by erythropoietin on rabbit bone marrow cell suspensions.

The effects of an erythropoietin (Ep)-rich plasma fraction and of a commercial preparation of purified Ep (Step I) on the cyclic adenosine monophosphate (cAMP) levels of suspended rabbit bone marrow cells at different incubation times (up to 10 min) were investigated. Both Ep preparations caused an early increase in cAMP concentration: using the plasma fraction a significant increase was found at the 6th, 7th, 9th and 10th min of incubation, whereas the purified Ep produces a significant increase at all incubation times, starting from 1 min. No effect was observed following incubation with fluorescein isothiocyanate (FITC)-inactivated Ep. These findings are discussed and possible role of cAMP as the intracellular messenger for Ep action is suggested.