Since Arimura et al (1975) reported the radioimmunoassay for somatostatin (GIF), the concentration of GIF in various organ and brain regions were determined by radioimmunoassay. Dubois et al (1975) reported that immunohistochemically somatostatin was located in the discrete cells of the pancreas as well as the hypothalamus, and from this result, they presented the concept of local hormone instead of systemic hormone which was up to that time accepted in endocrinology.
In this study, we developed the high specific anti-GIF serum using rabbits, and with the micro immunodiffusion method, we demonstrated that the precipitin band formed a circular fusion between the GIF and anti-GIF serum. This pattern of reaction was also seen in decidual immunodiffusion.
In addition, we developed the radioimmunoassay for GIF using this anti-serum and. measured immunoreactive GIF-like substances in villi and decidua of early pregnancy. The concentration of GIF-like substance with 2 N acetic acid extracted of villi and decidua were 0 to 30 pg/0.1 g dry weight.
At the same time, we demonstrated the presence of GIF-like substance-containing cells in the villi and decidua by indirect immunofluorescent method. The intensity of immunofluorescence was in cytotrophoblast rather than syncytiotrophoblast, and decidual stromal cell also reacted to the immunofluorescence.
