Prolactin, growth hormone, and IGF-1 in ankles and plasma of adjuvant arthritic rats

In this study we have investigated the levels of prolactin, growth hormone, and insulin-like growth factor-1 in plasma and in tissue extracts of ankle joints of rats with acute or chronic adjuvant arthritis using enzyme immun oassay (EIA) and radioimmunoassay (RIA). We found a stable content of prola ctin in plasma of the different groups but a significantly increased concen tration of growth hormone was observed in the plasma of the group with chro nic arthritis. Moreover, an increased concentration of insulin-like growth factor-1 was noted in the plasma of the acute group. This evidently had ret urned to normal levels in the chronic group. In contrast, decreased concent rations of prolactin, growth hormone, and insulin-like growth factor-1 were found in tissue extracts of ankle joints of the group with chronic arthrit is. The changes in the levels of these hormones in adjuvant arthritis might suggest that they play a role in the pathogenesis of the disease. Understa nding the mechanism(s) of hormonal participation in adjuvant arthritis may open new treatment strategies for rheumatoid arthritis and other inflammato ry disorders.