Synthesis and Release of Steroids in Intestines from Cynomolgus Monkeys (Macaca fascicularis)

Abstract To examine the synthesis and release of steroids in intestinal tissues from cynomolgus monkeys (Macaca fascicularis), we performed the following experiments: 1) incubated prepared intestinal tissues with [3H]testosterone to study the conversion to other steroids; 2) used a radioimmunoassay to determine steroid levels in six segments of intestinal tissues and contents (duodenum, jejunum, ileum, cecum, colon, and rectum); 3) localized testosterone in the six intestinal segments by immunofluorescence histochemistry; and 4) determined steroid levels in feces from males and females of various ages by radio-immunoassay to examine a correlation between steroid levels and age or sex. In prepared intestinal tissues, testosterone was converted into androstenedione, 5α-dihydrotestosterone, and an unidentified substance; all of these steroids were detected in all segments of the intestinal tissues and contents by radioimmunoassay. Immunofluorescence showed that testosterone was located in all segments of int...