[Gastrointestinal hormones during pregnancy--immunoreactive secretin and gastrin in serum and fetal tissue (author's transl)].

The concentrations of immunoreactive secretin (S) and gastrin (G) in maternal peripheral vein (MV) during pregnancy and MV, umbilical artery (UA) and umbilical vein (UV) at delivery and fetal tissue of 19, 23 weeks of gestation obtained after therapeutic abortion were measured by specific radioimmunoassay. S-specific antisera was generated in rabbits against highly purified synthetic S. Newly synthesized S analog (Tyr1)-S was indicated by enzymic method. The radioimmunoassay of S was performed by double antibody method using synthetic S as standard. G was measured by RIA kit (Dainabot radioisotope Lab.). The sensitivity of the assays for S and G was 50 pg/ml. The fetal tissue were extracted by water-boiling method and purified by gel filtration on Sephadex G-25 column. The S levels in MV increase as gestational age advances and reach to the maximum levels of 248 +/- 150 pg/ml, while no increase tendency was noticed in G levels. The S levels in MV, UA and UV at delivery (n = 18) were 307 +/- 158 pg/ml, 460 +/- 166 pg/ml and 424 +/- 126 pg/ml, respectively. The S levels in cord blood is statistically higher than that in MV (p less than 0.05). The G levels in MV, UA and UV were 67 +/- 22 pg/ml, 101 +/- 63 pg/ml and 91 +/- 38 pg/ml. The differences of the values between MV and cord blood are significant (p less than 0.05). S like material in fetal upper gastrointestinal tracts was found high in concentration. The extract of fetal duodenum showed a displacement curve paralleled to that of the standard S. In addition, relatively high concentration of immunoreactive S was found in cerebral cortex obtained from fetus of 23 weeks of gestation. G concentration in fetal tissue was also demonstrated. The evidence of immunoreactive S and G in fetal blood and fetal gastrointestinal tracts was reported. These results may be of importance to provide the information in understanding the physiology of the fetus.