TY - JOUR
T1 - Subcellular localization of steroid hormone metabolism in rat liver
AU - Glaumann, Hans
AU - Gustafsson, Jan Åke
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1977/10
Y1 - 1977/10
N2 - The metabolism of 4-[4-14C]androstene-3,17-dione was studied in smooth- and rough-surfaced microsomes, plasma membranes, mitochondria, Golgi apparatus, and lysosomes isolated from rat liver. 5α-Reductase, 17β-hydroxysteroid reductase, 16α-, 6β-, and 7α-hydroxylase activities were measurable in all isolated subcellular fractions except in lysosomes which did not metabolize 4-androstene-3,17-dione. Steroid metabolism patterns in smooth and rough microsomes were very similar. The extent of microsomal contamination in the plasma membrane, Golgi apparatus, and mitochondrial and lysosomal fractions was measured both by ultrastructural (morphometric) analysis and by distribution analysis of "marker enzymes" and was less than 15, 3, 16, and 3%, respectively. Whereas it could not be excluded that the metabolisms of steroids in the Golgi apparatus enriched fraction occurred due to microsomal contamination, the data indicate that the steroid metabolism in isolated plasma membranes and mitochondria occurred due to the presence of steroid reducing and hydroxylating enzyme systems in these cell organelles. Indirectly, such a similarity in enzymatic makeup between different cell organelles would tend to support "the membrane flow hypothesis.".
AB - The metabolism of 4-[4-14C]androstene-3,17-dione was studied in smooth- and rough-surfaced microsomes, plasma membranes, mitochondria, Golgi apparatus, and lysosomes isolated from rat liver. 5α-Reductase, 17β-hydroxysteroid reductase, 16α-, 6β-, and 7α-hydroxylase activities were measurable in all isolated subcellular fractions except in lysosomes which did not metabolize 4-androstene-3,17-dione. Steroid metabolism patterns in smooth and rough microsomes were very similar. The extent of microsomal contamination in the plasma membrane, Golgi apparatus, and mitochondrial and lysosomal fractions was measured both by ultrastructural (morphometric) analysis and by distribution analysis of "marker enzymes" and was less than 15, 3, 16, and 3%, respectively. Whereas it could not be excluded that the metabolisms of steroids in the Golgi apparatus enriched fraction occurred due to microsomal contamination, the data indicate that the steroid metabolism in isolated plasma membranes and mitochondria occurred due to the presence of steroid reducing and hydroxylating enzyme systems in these cell organelles. Indirectly, such a similarity in enzymatic makeup between different cell organelles would tend to support "the membrane flow hypothesis.".
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U2 - 10.1016/0014-4800(77)90032-6
DO - 10.1016/0014-4800(77)90032-6
M3 - Article
C2 - 198241
AN - SCOPUS:0017712378
VL - 27
SP - 221
EP - 234
JO - Experimental and Molecular Pathology
JF - Experimental and Molecular Pathology
SN - 0014-4800
IS - 2
ER -