Distributional Uptake of γ-Globulin in Small Intestine of Neonatal Calves

Abstract

Newborn calves deprived of colostrum were used to determine distribution of uptake of γ-globulin labeled with iodine-125 in small intestine. Ten calves less than 12.5h of age (average 7h) were anesthetized, and intestines were exteriorized through an abdominal incision. Intestine was ligated into 10-cm segments, 70cm apart, beginning at the ileocecal junction and progressing anteriorally, then each segment injected with 100mg (∿ 1 µCi) labeled γ-globulin in 5ml electrolyte solution, and incubated for 1.5h. One additional segment was formed adjacent to segments 1,5, and 10 to assess uptake after .5h incubation with [iodine-125] γ-globulin. After prescribed γ-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 γ-globulin per gram of segment tissue. Distribution of γ-globulin uptake after 1.5h 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 γ-globulin, regression of uptake on segment position was a quadratic function with greatest uptake at 30% of cecumabomasum distance. Uptake was greater in segments exposed to γ-globulin for 1.5h than .5h.