Lipophilic conjugates fenvalerate

Okuno, Y., T. Seki, S. Ito, H. Kenoko, T. Watanabe, T. Yamada, and J. Miyamoto. 1986. Differential metabolism of fenvalerate and granuloma formation. II. Toxicological significance of a lipophilic conjugate from fenvalerate. Toxicol. Appl. Pharmacol. 83 157-169. 

In addition, three types of lipophilic conjugates have been found in pyrethroid metabolism studies (Fig. 4). They are cholesterol ester (fenvalerate) [15], glyceride (3-PBacid, a common metabolite of several pyrethroids) [16], and bile acid conjugates (fluvalinate) [17]. It is noteworthy that one isomer out of the four chiral isomers of fenvalerate yields a cholesterol ester conjugate from its acid moiety [15]. This chiral-specific formation of the cholesterol ester has been demonstrated to be mediated by transesterification reactions of carboxylesterase(s) in microsomes, not by any of the three known biosynthetic pathways of endogenous cholesterol esters... 

Similarly, in other mouse tissues and also in rat tissues, the presence of CPIA-cholesterol ester was demonstrated following administration of the Ba isomer or fenvalerate. Thus, CPIA-cholesterol ester proves now to be a novel type of conjugate which is more lipophilic than the parent compound and CPIA. 

---