Cyclic nucleotides and haemoglobin concentration in rabbit bone marrow cell suspensions stimulated by purified erythropoietin.

Abstract

This study was conducted to determine the possible correlations between cyclic nucleotides cyclic adenosine monophosphate (cAMP) and cyclic guanine monophosphate (cGMP), and haemoglobin (Hb) concentration in nucleated cell suspensions of rabbit bone marrow incubated with erythropoietin (Ep). The levels of cAMP and cGMP were measured following the addition of different Ep concentrations to the suspensions. The Hb concentration was also measured in suspensions treated with Ep, dibutyryl cAMP (db-cAMP) or dibutyryl cGMP (db-cGMP), respectively. The following results were obtained: (1) upon the addition of 1 IU ml-1 Ep, an increase of cAMP levels was related to an increase in Hb concentration; while a decrease of Hb concentration was related to an increase of cGMP levels obtained when 0.1 IU ml-1 Ep was present in the incubation mixture. (2) A mimetic effect on Hb concentration was obtained upon the addition of db-cAMP or db-cGMP to the suspensions. (3) A quantitative correlation was found between the cAMP/cGMP ratio and Hb levels in cellular suspensions. This rapport was reviewed with respect to the controls as a decrease in Hb concentration when the ratio is less than one and an increase in Hb concentration when the ratio is greater than one.