DETECTION AND LOCALIZATION OF AUTOFLUORESCENT SUBSTANCES IN THYMUS TISSUE OF SHEEP

An oxygenated sterol was detected by chemical analysis of sheep thymus lipid extracts. It was characterized as 7 beta-hydroxycholesterol, wh ich is well known:for its biological activity. Using fluorescence micr oscopy, attempts were made to correlate this substance to particular h istological structures of the thymus tissue. Microscopy revealed an in tense yellow-green primary fluorescence distributed throughout the ent ire thymic parenchyma, which was predominant in the cortico-medullary junction, the vicinity of the Hassall's bodies and the subcapsular spa ce. This indicated an accumulation of the fluorogenic substance in spe cial tissue structures of sheep thymus. This result can be assumed as specific for the thymus, since such primary fluorescence was absent fr om other simultaneously investigated organs, such as the adrenal.