AJP - Gastrointestinal and Liver Physiology, Vol 268, Issue 1 41-G46, Copyright © 1995 by American Physiological Society

ARTICLES

Do pancreatic proteases play a role in processing prolactase and/or in the postweaning decline of lactase?

P. Keller, J. C. Poiree, J. Giudicelli and G. Semenza
Department of Biochemistry, Swiss Federal Institute of Technology, Zurich.

To assess the role of pancreatic proteases in the proteolytic processing and in the postweaning decline of lactase-phlorizin hydrolase (LPH), we have determined lactase activity and the different LPH forms in postweaned rats in which a jejunal loop was excluded from contact with pancreatic secretions by a jejunal bypass procedure. As a control for the absence of pancreatic proteases, pro-sucrase-isomaltase (proSI), which is known to be split by pancreatic proteases into heterodimeric SI, was used. Nearly all proLPH was processed to mature LPH, indistinguishable from LPH isolated from control animals. SI was found only in the unsplit pro form, whereas it was normally processed to the heterodimeric SI in the control tissues. There were no significant differences in lactase and sucrase activities in operated and in sham-operated control animals. We conclude that pancreatic secretions are not essential for the processing of proLPH to LPH or in the postweaning decline of LPH.

This article has been cited by other articles:

				J. E. Mesonero, S. M. Gloor, and G. Semenza Processing of Human Intestinal Prolactase to an Intermediate Form by Furin or by a Furin-like Proprotein Convertase J. Biol. Chem., November 6, 1998; 273(45): 29430 - 29436. [Abstract] [Full Text] [PDF]