Detection of aromatase in human articular cartilage tissue, in primary human articular chondrocytes and in chondrocyte cell lines C-28/I2 and T/C-28a2. (A) Aromatase mRNA (177 bp) was detected in articular cartilage tissue (lane 1), in cultured articular chondrocytes (lane 2) and in immortalized chondrocytes of cell lines C-28/I2 (lane 3) and T/C-28a2 (lane 4). Diethylpyrocarbonate water served as a negative control (lane 5). (B) Western blot analysis of aromatase using the antibody SM2222P in articular cartilage tissue from patients of both sexes and different ages. Aromatase protein is detected at 55 kDa in articular cartilage from females ages 3, 7, 38, 52, 62 and 83 years and from men at ages 22, 24, 28, 33, 41, 48, 59, 66 and 73 years. (C) Western blot analysis of aromatase in various control tissues. Aromatase protein is found in both primary sex hormone–dependent organs, such as placenta (lane 1), testicle (lane 2), ovary (lane 3), uterus (lane 7) and prostate (lane 8), and in primary non-sex-hormone–dependent organs, such as lung (lane 4), lacrimal gland (lane 5), heart (lane 6) and nasal turbinate epithelium (lane 9).