Effect of cortisone on intestinal uptake of lead in the suckling rat.

A previous study showed that there is extensive uptake of lead by the duodenum and the ileum of the suckling rat. At both sites, uptake declines with advancing age. This paper reports the effects of administration of cortisone acetate on in vivo lead uptake in 14- to 15-day-old rats. The results indicate that the duodenal uptake component is unaffected by hormone treatment whereas the ileal uptake component is markedly suppressed. There was no significant difference in blood lead concentrations in cortisone-treated pups as compared with vehicle-treated controls. We conclude that lead absorption in the suckling rat occurs primarily in duodenum and is not under glucocorticoid control. The ileal uptake of lead probably represents intestinal retention rather than absorption: its responsiveness to cortisone would be consistent with uptake via pinocytosis.