title: PDE7B is involved in nandrolone decanoate hydrolysis in liver cytosol and its transcription is up-regulated by androgens in HepG2.
abstract: Most androgenic drugs are available as esters for a prolonged depot action. However, the enzymes involved in the hydrolysis of the esters have not been identified. There is one study indicating that PDE7B may be involved in the activation of testosterone enanthate. The aims are to identify the cellular compartments where the hydrolysis of testosterone enanthate and nandrolone decanoate occurs, and to investigate the involvement of PDE7B in the activation. We also determined if testosterone and nandrolone affect the expression of the PDE7B gene. The hydrolysis studies were performed in isolated human liver cytosolic and microsomal preparations with and without specific PDE7B inhibitor. The gene expression was studied in human hepatoma cells (HepG2) exposed to testosterone and nandrolone. We show that PDE7B serves as a catalyst of the hydrolysis of testosterone enanthate and nandrolone decanoate in liver cytosol. The gene expression of PDE7B was significantly induced 3- and 5- fold after 2 h exposure to 1 μM testosterone enanthate and nandrolone decanoate, respectively. These results show that PDE7B is involved in the activation of esterified nandrolone and testosterone and that the gene expression of PDE7B is induced by supra-physiological concentrations of androgenic drugs.
authors.affiliation: Division of Clinical Pharmaclogy, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Stockholm, Sweden.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Strahm
authors.affiliation: Division of Clinical Pharmaclogy, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Stockholm, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Rane
authors.affiliation: Division of Clinical Pharmaclogy, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Stockholm, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Ekström
keywords: androgens; doping; nandrolone decanoate; phosphodiesterase 7B; testosterone