Bar, A., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel
Hurwitz, S., Institute of Animal Science, The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel

1. 1. Intestinal and uterine calcium-binding protein (CaBP) in the fowl (Gallus domesticus) were compared by the Chelex assay and gel electrophoresis; their response to physiological and nutritional stimuli was studied. 2. 2. Molecular weight of uterine CaBP was found to be slightly higher than that of intestinal CaBP. 3. 3. Uterine and intestinal CaBP increased within 24 hr of the onset of egg production; both decreased as egg production ceased. 4. 4. Uterine CaBP level was slightly higher during periods of uterine inactivity than during periods of egg shell formation. There was no difference in uterine CaBP between laying hens which secreted heavy or light shells. 5. 5. A long-term calcium restriction did not influence uterine CaBP level. 6. 6. The similarities and differences between uterine and intestinal CaBP, and the possible role of CaBP in uterine calcium transport are discussed. © 1973.