Temporal-specific and spatial-specific patterns of neurotensin gene expression in the small bowel.
Expression of the neurotensin/neuromedin N (NT/N) gene is developmentally regulated in a temporal- and spatial-specific pattern in the small bowel. The purpose of our study was to determine 1) whether the temporal expression of NT/N could be altered by ectopic placement of small bowel and 2) whether the spatial-specific expression of NT/N could be altered by different diets. We found that the relative temporal pattern of NT/N expression was unchanged in rat jejunal and ileal xenografts implanted into the flanks of athymic nude mice. To determine whether the spatial-specific pattern of NT/N expression could be altered by different luminal nutrients, 28-day-old rats were randomized to receive chow or chemically defined liquid diets for 60 days at which time the jejunoileum was divided into eight equal segments, and NT/N expression was analyzed. The normal pattern of increasing levels of NT/N mRNA along the jejunum-to-ileum axis was not altered by any of the liquid diets. In contrast to NT/N, we found that expression of sucrase-isomaltase varied greatly depending on both location and type of luminal nutrients. We conclude that the strict temporal- and spatial-specific pattern of NT/N expression is not affected by either location or luminal contents, thus suggesting an intrinsic program of NT/N gene expression. Furthermore, we speculate that the NT/N gene may provide a useful endocrine paradigm to investigate the factors regulating the establishment and maintenance of certain cell lineage-specific patterns along the cephalocaudal axis of the gut.
Department of Surgery, University of Texas Medical Branch, Galveston 77555-0533.
B M
BM
Evers
J A
JA
Ehrenfried
X
X
Wang
C M
CM
Townsend
J C
JC
Thompson
D000375:Aging / Q000502:physiology*; D000818:Animals; D004702:Endocrine Glands / Q000166:cytology / Q000502:physiology; D004750:Enteral Nutrition; D015870:Gene Expression; D007082:Ileum / Q000502:physiology; D007421:Intestine, Small / Q000166:cytology / Q000502:physiology*; D007583:Jejunum / Q000502:physiology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009496:Neurotensin / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D014018:Tissue Distribution
D012333:RNA, Messenger; D009496:Neurotensin