Slc10a6, also known as the sodium-dependent organic anion transporter (SOAT), is a plasma membrane transporter that specifically transports 3'- and 17'-monosulfated steroid hormones, such as estrone sulfate and dehydroepiandrosterone sulfate, into target cells. These sulfo-conjugated steroids are precursors for the intracrine formation of active estrogens and androgens, contributing to the regulation of steroids in peripheral tissues [1].

In Slc10a6-/-knockout mice, adipocytes increased in size in certain adipose tissues of female and male mice, suggesting adipocyte hypertrophy, while serum levels of adiponectin, resistin, and leptin were comparable to wild-type mice. The knockout mice were fertile with normal spermatogenesis and sperm vitality, but male knockout mice had significantly higher serum levels of cholesterol sulfate [2,3]. Inflammation-associated upregulation of Slc10a6 mRNA was observed in mouse liver and macrophage cell lines, and its substrate dehydroepiandrosterone sulfate enhanced LPS induction of a pro-inflammatory chemokine in macrophages, suggesting its contribution to the hepatic inflammatory response [4].

In conclusion, Slc10a6 plays a role in the supply of steroids in peripheral target tissues, including adipose tissue and the testis. Gene knockout mouse models have revealed its functions in adipocyte development, spermatogenesis, and the hepatic inflammatory response. Understanding Slc10a6 could potentially provide insights for endocrine-based therapy of steroid-responsive diseases [1,2,3,4].