Estrogen binding proteins in rat pancreas.

Abstract Estrogen binding proteins (EBP) of pancreatic acinar cells of a number of species have been reported by us previously. This work examines the organ specificity of EBP. Microsomal fractions of pancreas. liver, parotid gland, kidney, lung, abdominal muscle and submaxillary gland were incubated with estra-diol (E 2 ). After the microsomal pellets of each tissue had adsorbed E 2 , the pellets were washed twice by resuspension and recentrifugation and the last supernatant obtained was tested for E 2 binding by sucrose density gradient. Over 80% of the E 2 was found in the bound form in the supernatant of the pancreatic microsomal pellet, whereas no bound E 2 was found in the supernatants of the microsomal pellets of any of the other tissues tested. Organ specificity became also apparent by immunodiffusion tests of extracts of different tissue against antibodies to EBP. One strong and some weaker precipitin lines are produced by pancreatic extracts. Weaker precipitin lines were observed by extracts of submaxillary gland and liver. Precipitin lines were also visible from extracts of epididymis, prostate, testis, muscle, parotid gland, lymph nodes, and. maybe, a weak reaction with thyroid. No precipitin lines were observed with hypothalamus, uterus or ovaries. Organ specificity was made noticeable by Ouchterlony immuno-diffusion plates which showed that the strong precipitin line of pancreatic extracts is not shared with those of extracts from other tissues.