Variable response of male human articular chondrocytes to 17β-estradiol. Chondrocytes were isolated from three male donors (<30 years) with no evidence of OA. Confluent cultures of second-passage cultures were treated with 10-8 to 10-10 M 17β-estradiol for 24 hours and proteoglycan production was measured as a function of 35S-sulfate incorporation into sulfated glycosaminoglycans, a hallmark of cartilage extracellular matrix. Data are means ± SEM, N = 6 independent cultures per variable. *p < 0.05, treatment v. control. Cells from two of the donors exhibited no response to the hormone in two different sets of experiments, whereas cells from one of the donors were responsive to the hormone. Data are provided courtesy of Ramsey Kinney, MD, PhD, Department of Orthopaedics, Emory University School of Medicine, Atlanta, GA.