Distributional uptake of gamma-globulin in small intestine of neonatal calves.

Newborn calves deprived of colostrum were used to determine distribution of uptake of gamma-globulin labeled with iodine-125 in small intestine. Ten calves less than 12.5 h of age (average 7 h) were anesthetized, and intestines were exteriorized through an abdominal incision. Intestine was ligated into 10-cm segments, 70 cm apart, beginning at the ileocecal junction and progressing anteriorally, then each segment injected with 100 mg (appoximately 1 microCi) labeled gamma-globulin in 5 ml electrolyte solution, and incubated for 1.5 h. One additional segment was formed adjacent to segments 1, 5, and 10 to assess uptake after .5 h incubation with [iodine-125] gamma-globulin. After prescribed gamma-globulin exposure, segments were excised; then volume of lumen contents, segment weight, and tissue activity were measured. The location of each segment was the percentage of distance from cecum to abomasum. Uptake was milligrams gamma-globulin per gram of segment tissue. Distribution of gamma-globulin uptake after 1.5 h incubation was a cubic function of segment position. Uptake was greatest in a region 15% of the cecum-abomasum distance and declined progressively toward the abomasum. After .5-h incubation with gamma-globulin, regression of uptake on segment position was a quadratic function with greatest uptake at 30% of cecum-abomasum distance. Uptake was greater in segments exposed to gamma-globulin for 1.5 h than .5 h.