Abstract
The responses of human fetal catecholamine storing tissues, the paraganglia and adrenal medulla to severe oxygen deficiency were tested by using perfusion techniques. The changes in catecholamine content of the target organs were registered by demonstrating the formaldehyde induced fluorescence exhibited by catecholamines. A definite decrease in the intensity of the catecholamine specific fluorescence was observed regularly in the paraganglia after 10–15 min hypoxia. Only very slight changes occurred occasionally in the corresponding adrenal medullae. The role of the target organs and the catecholamine release during oxygen deficiency are discussed.