Blood, 1972, Vol. 39, No. 1, pp. 13-22.
© 1972 American Society of Hematology, Inc.
-Aminolevulinic Acid Synthetase Activity in Human
Plasma: Relation to Erythropoiesis and Evidence of
Induction in Erythropoietic Porphyria
KEN MIYAGI 1 and
C. J. WATSON 1
1 University of Minnesota Medical Research Unit, Northwestern Hospital,
Minneapolis, Minn.
Measurement of 
-aminolevulinic acid
synthetase (ALA-S) activity in human
plasma has been carried out with samples from normal individuals, cases of
erythropoietic porphyria (EP) and erythropoietic protoporphyria (EPP), and of
the three principal forms of hepatic porphyria—acute intermittent porphyria,
variegate porphyria, and porphyria cutanea tarda. The method of measurement
depends on formation of 14C-ALA when
the plasma is incubated with 14C-succinic
acid, succinyl-Co A synthetase, glycine,
and other essential substances. The normal samples, as well as those from the
hepatic porphyria cases, had small but
significant activity of the same extent;
those from the erythropoietic group
showed consistently higher values, especially in the two cases of congenital type.
A remarkably high value in one of these
cases in which there was outspoken erythropoiesis was believed to be related to
the presence of many fluorescing normoblasts in the peripheral blood. Following
multiple transfusions these disappeared
concomitantly with striking reduction
of the porphyria. The plasma ALA-S
activity declined to 1.4% of the pretransfusion value. These results are considered
in respect to the question of induction of
ALA-S in the developing red cells of the
disease, special attention being given to
the minor increase of ALA-S activity in
the plasma of a nonporphyric individual
whose peripheral blood contained large
numbers of circulating normoblasts.
Submitted on May 11, 1971
Revised on July 19, 1971
Accepted on July 20, 1971
