| Abstrakt: |
Summary: The experiments reported here illustrate a few of the factors apart from genes which can influence hormone-responsive generation of cyclic adenosine 3':5'-monophosphate in human fibroblasts. For both normal and cystic fibrosis fibroblasts, the isoproterenol stimulation ratio was maximal 2 to 3 days after subculture and declined thereafter; prostaglandin E1stimulation ratio was maximal 7 to 10 days after subculture, Cells dislodged from the plate by either scraping or trypsinization had reduced isoproterenol or prostaglandin E1stimulation ratios compared to cells studied in situ. Fibroblasts from healthy controls and cystic fibrosis patients plated simultaneously and grown in three different culture conditions responded similarly to the change in growth conditions. Addition to the incubation medium of polyamines, calcium, magnesium, or guanosine triphosphate did not alter the stimulation ratios for isoproterenol or prostaglandin E1. Repeated measures analysis indicates that cellular content of cyclic adenosine 3':5'-monophosphate is not a reliable measure for comparing cell lines; isoproterenol stimulation ratio is a reliable measure, but there is large variation from cell line to cell line. Isoproterenol stimulation ratio was the same for normal and cystic fibrosis fibroblasts in each of the three culture conditions tested at both three and ten days after subculture.Speculation: Because of the unexplained day-to-day variability in cellular cyclic adenosine 3':5'-monophosphate content, the multiple exogenous influences on hormone-responsive cyclic adenosine 3':5'-monophosphate, and the potential limitations of studying fibroblasts only on their support so as not to perturb the membrane-associated receptor adenylate cyclase system, the cultured skin fibroblast may not be the optimal system for population studies of adrenergic-responsive adenylate cyclase in human disease. |
