Androgen regulation of the expression of OCTN2, a high affinity carnitine transporter, in the epididymis and other tissues

Abstract

OCTNZ is a transport protein and a member of a superfamily of organic cation transporters and has been shown to transport a variety of substrates, including camitine. The transport of the substrate is unique among this family of transport proteins as it is sodium-dependant, and it has been shown that this transporter is a physiologically relevant camitine transporter, as naturally occurring mutations in the gene encoding this transporter result in the clinical manifestation of the syndrome known as primary camitine deficiency. With the acceptance of OCTNZ's physiological role in camitine homeostasis, further scientific inquiries need to be made to definitively show that OCTN2 is a molecular mechanism that underlies many of the observations made in the field of camitine research in past century. Multiple investigators have reported the effect and relationship between androgen levels and carnitine transport, but until the discovery of OCTN2 and its role in camitine homeostasis, the effect of androgens on the molecular mechanism responsible for these observations could not be proven. The results of the research described here should provide conclusive evidence that androgen levels regulate levels of OCTNZ expr!lSsion in both tissues of the male rat and in a human cell line, through either a direct or indirect mechanism, and that the effect on the regulation of expression is consistent with transport data :from previous researchers.