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Phospholipid requirement of progesterone 5α‐reductase from gastric mucosa microsomes of guinea pig
Author(s) -
Ichihara Kosuke,
Tanaka Chikage
Publication year - 1991
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02536599
Subject(s) - lysophosphatidylcholine , reductase , lysophosphatidic acid , phosphatidylethanolamine , phospholipid , biochemistry , lysophosphatidylethanolamine , chemistry , microsome , phosphatidylserine , phosphatidylcholine , guinea pig , clinical chemistry , biology , enzyme , endocrinology , receptor , membrane
Abstract Progesterone 5α‐reductase partially purified from gastric mucosa microsomes was stimulated by short‐chain synthetic phosphatidylcholines (PC), such as dilauroyl PC, but not by various PC from biological sources. Phosphatidylserine (PS) activated the gastric 5α‐reductase to a limited extent compared to the liver 5α‐reductase described previously [Ichihara, K., and Tanaka, C. (1987) Biochem. Biophys. Res. Commun. 149 , 482–487]. In search of more effective phospholipid activators, we tested the effects of various lysophospholipids on 5α‐reductase activity. Strongly stimulatory effects were observed when lysophosphatidylcholine (lysoPC) and lysophosphatidylethanolamine (lysoPE) were used instead of PC and phosphatidylethanolamine. Examination of synthetic lysoPC and lysoPE differing in acyl chain lengths showed that fatty chains of 12 to 16 carbons were effective in stimulating the 5α‐reductase. By contrast, other lysophospholipids such as lysophosphatidic acid, lysophosphatidylglycerol or lysophosphatidylserine (lysoPS) greatly inhibited 5α‐reductase activity. These findings suggest that gastric 5α‐reductase may be under dual regulation; lysoPC and lysoPE may play important roles as positive effectors, whereas lysophosphatidic acid, lysophosphatidylglycerol and lysoPS act as negative effectors in progesterone 5α‐reductase regulation.