Received June 23, 2006
Revised July 19, 2006
Accepted after revision August 30, 2006

¹ Tottori University
² NRL Pharma Inc.
³ Rakuno-Gakuen University

^* To whom correspondence should be addressed. E-mail: takeuchi{at}muses.tottori-u.ac.jp.

	Abstract

We have previously demonstrated that intestinally infused bovine lactoferrin (bLF) was transported into the blood circulation via the lymphatic pathway, not via portal circulation. Thus, in the present study, we further investigated whether intra-gastrically infused enteric-formulated bLF (EF-bLF) was more efficiently absorbed from the intestine in adult rats. The rats were randomly divided into three groups: 30 and 300 mg/kg non-enteric-formulated bLF (non-EF-bLF) groups and a 30 mg/kg EF-bLF group. Thoracic lymph was collected from a thoracic lymph duct under anesthesia. bLF was infused into the stomach or duodenal lumen by a needle for a period of over 1 min at a dose of 1 ml/kg. The bLF transported into the lymph was assayed quantitatively using by double-antibody enzyme-linked immunosorbent assay (ELISA). Following the intra-gastric administration of bLF, the three groups showed almost the same lymph flow, but the bLF concentration in the lymph fluid in the EF-bLF group increased significantly and peaked 3 h after administration. In intra-duodenal administration, the bLF concentration in the lymph fluid of the higher non-EF-bLF group was significantly high as compared with those of the other groups. The amount of absorbed bLF in the EF-bLF group was, however, about ten times higher than that in the lower non-EF-bLF group, when it was administered intra-gastrically. These data show that enteric-formulated bLF is less susceptible to gastric pepsin and is more efficiently absorbed from the intestine than is non-enteric-formulated bLF in oral administration.

Key Words: Absorption, Intestine, Lymph