LS14: a novel human adipocyte cell line that produces prolactin.

Adipose tissue is an integral component within the endocrine system. Adipocytes produce numerous bioactive substances, and their dysregulation has serious pathophysiological consequences. We previously reported that human adipose tissue from several depots produces significant amounts of prolactin (PRL). To study locally produced PRL, we sought an acceptable in vitro model. Consequently, we developed an adipocyte cell line derived from a metastatic liposarcoma. The cell line, designated LS14, has been in continuous culture for 2 yr. These cells exhibit many properties of primary preadipocytes, including the ability to undergo terminal differentiation, as judged by morphological alterations, lipid accumulation, and increase in glycerol-3-phosphate dehydrogenase. LS14 cells express many adipose-associated genes, such as adipocyte fatty acid-binding protein (aP(2)), hormone-sensitive lipase, lipoprotein lipase, preadipocyte factor 1, adiponectin, leptin, and IL-6. Similar to primary adipocytes, LS14 cells also produce and respond to PRL, thus making them an attractive model to study adipose PRL production and function. The expression of PRL was confirmed at the transcriptional level by RT-PCR, and PRL secretion was determined by the Nb2 bioassay. Addition of exogenous PRL to LS14 cells resulted in a dose-dependent inhibition of IL-6 release. In summary, we have established a novel human adipocyte cell line with many characteristics of primary adipocytes. The LS14 cells open up new avenues for research on human adipocyte biology and add to the repertoire of nonpituitary, PRL-producing cell lines.