Hamster flank organ hydrolase and lipase activity.

The hydrolase and lipase activities of homogenates of the golden Syrian hamster flank organ (sebaceous complex) and skin were studied using synthetic fluorogenic substrates, 4-methylumbelliferone butyrate (4 MUB) or 4-methylumbelliferone palmitate (4 MUP). Homogenates of both flank organ and skin demonstrate a higher level of hydrolase activity (MUB substrate) than lipase activity. Flank organ however is enriched in lipase activity (4 MUP substrate) demonstrating 8 times as much activity as the skin. Systemic androgen treatment of female hamsters significantly stimulates the flank lipase activity while topical estradiol or the antiandrogen flutamide significantly decrease lipase. Testosterone and estradiol have a converse and weaker influence on hydrolase activity suggesting that this activity may be associated with different cell types. These effects do not appear to be direct since these compounds do not inhibit either enzyme in vitro. This data suggests a role for endogenous tissue lipases in the maturation of sebaceous tissue. Tetracycline and retinoic acid inhibit the activity of both enzymes in vitro. Retinoic acid also inhibited both in vivo while tetracycline inhibited only the lipase.