This proposal concerns the nature of hormones and hormonal changes occurring in nematodes during the process of aging. Five key hormone types will be sought: cyclic AMP, prostaglandins, steroidal hormones, juvenile hormone, and serotonin. Experiments are described for the detection of each of the hormonal types and for demonstration of their formation by the nematodes. Changes in hormone levels prior to, during, and after ecdysis will be examined in an effort to learn more of the hormones and hormonal changes important to this process in nematodes. Changes in hormone levels and of key enzymes in hormone production will be studied in L2, L3, L4 larvae and in young and old adults. This may shed some light on the nature of the hormonal systems of importance in aging in these organisms.