Adipocytes play an important role in energy storage and metabolism. Adipocyte differentiation is a developmental process that is critical for metabolic homeostasis and nutrient signaling. It is controlled by complex actions involving gene expression and signal transduction. Preadipocytes are present throughout adult life in adipose tissue and can proliferate and differentiate into mature adipocytes, contributing to increased adipose tissue mass. In vitro studies indicate that various tissue-derived preadipocytes exhibit different lipid accumulations, adipogenic transcription factor expression, and TNFα-induced apoptosis. There is also a close relationship between adipocyte differentiation and many physiological and pathological processes including fat metabolism, obesity, diabetes, hyperlipidemia, and breast cancer. HPA-s from ScienCell Research Laboratories are isolated from human subcutaneous fat tissue. HPA-s are cryopreserved at passage one and delivered frozen. Each vial contains >1 x 106 cells in 1 ml volume. HPA-s are characterized by immunofluorescence with antibodies specific to CD44 or CD90, and lipid staining after differentiation. HPA-s are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HPA-s are guaranteed to further expand for 5 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Preadipocyte Medium (PAM, Cat. #7211) for culturing HPA-s in vitro. Preadipocyte Differentiation Medium (PADM, Cat. #7221) can be used for in vitro differentiation of preadipocytes into mature adipocytes, and then followed by Adipocyte Medium (AdM, Cat. #7201), which maintains mature adipocytes after differentiation.