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Hair Loss Study Abstract: Novel steroid 5 alpha-reductase inhibitor FK143: its dual inhibition against the
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Title
Novel steroid 5 alpha-reductase inhibitor FK143: its dual inhibition against the two
isozymes and its effect on transcription of the isozyme genes.
Author
Kojo H; Nakayama O; Hirosumi J; Chida N; Notsu Y; Okuhara M
Address
Exploratory Research Laboratory, Fujisawa Pharmaceutical Co., Ltd, Tsukuba, Japan.
Source
Mol Pharmacol, 1995 Sep, 48:3, 401-6
Abstract
Recent cloning of the cDNAs for the two isozymes of steroid 5 alpha-reductase (EC
1.3.99.5) allowed individual expression of the isozymes and permitted us to investigate
the action of steroid 5 alpha-reductase inhibitors against the individual isozymes without
any ambiguity that may be caused by coexistence of the isozymes in tissue preparations. We
examined the kinetic characteristics of FK143
(4-[3-[3-[bis(4-isobutylphenyl)methylamino]benzoyl]-1H -indol-1- yl]butyric acid), a novel
nonsteroidal steroid 5 alpha-reductase inhibitor against cloned human and rat steroid 5
alpha-reductase isozymes. FK143 was shown to inhibit both isozymes equally. The mode of
the inhibition of FK143 against both isozymes was noncompetitive. The inhibition constants
Kie and Kies of FK143 for human types 1 and 2 were 27.0 and 19.6 nM and 19.9 and 14.5 nM,
respectively. Species selectivity between human and rat of the inhibitory activity of
FK143 against both isozymes was not found. We also examined the effect of FK143 on the in
vivo expression of the genes encoding for the rat steroid 5 alpha-reductase isozymes.
FK143 reduced the testosterone-induced increase in the amount of the type 1 mRNA in
castrated rat, whereas it did not substantially affect the amount of the type 2 mRNA.
Language of Publication
LA=ENG
Unique Identifier
96018831
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