Abstract
The expression of segmental functions during renal epithelial ontogeny depends on cell intrinsic mechanisms and on extracellular factors. Differential segmental changes of ion transport, osmotic permeability and enzyme activities have been studied in this laboratory by micropuncture in vivo, perfusion of isolated nephron segments in vitro and,recently,by primary cultures of renal epithelia from defined nephron segments.
The contributions of loop of Henle epithelia to renal osmoregulation during ontogeny are given as an example. In vivo, net fluid transport increases by a factor of 2.5 while proximal volume delivery to the loop changes from 4.3 to 7.1 nl/min,and luminal osmotic activity at the macula densa site decreases from 284 to181 mOsm.In vitro, the thick ascending segment is characterized by a low and constant osmotic permeability during ontogeny while the maximal transepithelial gradient for Na+ increases from 40 to 75 mM with differentiation.Segmental activities of glycolytic and Na+-transfer enzymes increase greatly. In culture, epithelial cell proliferation from the ascending loop is stimulated selectively by hormonal supplements. Appropriate techniques may thus provide insight into the mechanisms by which segmental functions are expressed during nephron ontogeny.
Log in or create a free account to read this content
Gain free access to this article, as well as selected content from this journal and more on nature.com
or
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Horster, M. ANALYSIS OF NEPHRON SEGMENTAL FUNCTIONS IN VIVO AND IN VITRO DURING EPITHELIAL ONTOGENY. Pediatr Res 14, 987 (1980). https://doi.org/10.1203/00006450-198008000-00083
Issue date:
DOI: https://doi.org/10.1203/00006450-198008000-00083
