OBJECTIVE Sex steroids exert a significant influence on the health and well-being of the ocular surface and adnexa. These hormones affect multiple aspects of the lacrimal and meibomian glands, conjunctiva, and cornea, and have been linked to the development of many ocular surface pathologies. We hypothesize that these hormone actions, as in other tissues, occur predominantly after the local synthesis of androgens and estrogens from adrenal precursors. To begin to test this hypothesis, we analyzed whether human ocular surface and adnexal tissues and cells contain the steroidogenic enzyme mRNAs necessary for the intracrine synthesis and metabolism of sex steroids. METHODS Total RNA was isolated from human lacrimal and meibomian glands and immortalized corneal and conjunctival epithelial cells. Samples were reverse transcribed to cDNA and analyzed for the presence of enzyme mRNAs by real-time PCR. Positive and negative controls included human placental cDNA and the absence of template, respectively. RESULTS Our results show that human lacrimal and meibomian glands and corneal and conjunctival epithelial cells contain the mRNAs for steroid sulfatase, 3beta-hydroxysteroid dehydrogenase (HSD)-Delta-Delta-isomerase type 1, 17beta-HSD types 1 and 3, aromatase, and glucuronosyltransferase. In contrast, only lacrimal and meibomian tissues appeared to contain detectable mRNA for sulfotransferase. CONCLUSIONS If the corresponding mRNAs are translated, our results indicate that human ocular surface and adnexal tissues contain the enzymatic machinery necessary for the intracrine synthesis and metabolism of sex steroids.