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The use of exogenous δ-aminolaevulinic acid for the studies of the regulation of haem synthesis in rabbit reticulocytes

1973; Elsevier BV; Volume: 304; Issue: 1 Linguagem: Inglês

10.1016/0304-4165(73)90121-9

1872-8006

Přemysl Poňka, J Neuwirt, J Borová,

Neonatal Health and Biochemistry

δ-Amino [4-14C]laevulinate added to reticulocytes incubated in vitro is incorporated into haem. Exogenous δ-aminolaevulinate restores the incorporation of 59Fe into haem in reticulocytes which had been treated with isonicotinic acid hydrazide (INH) or penicillamine and were hence unable to synthesize δ-aminolaevulinate. On the other hand, the addition of δ-aminolaevulinate does not restore the incorporation of Fe into reticulocytes incubated with haemin. The inhibition of the incorporation of iron is neither restored by δ-aminolaevulinate in reticulocytes incubated with cycloheximide (which inhibits globin synthesis and thus elevates the free intracellular haem pool). These results suggest that in intact reticulocytes haemin does not inhibit δ-aminolaevulinate synthetase. This conclusion is further supported by the finding that the pattern of incorporation of [2-14C]glycine and δ-amino[4-14C]-laevulinate into haem differs in reticulocytes incubated with an inhibitor of δ-aminolaevulinate synthetase (INH) and in reticulocytes incubated with haemin and cycloheximide.