Site of Action of Antidiuretic Hormone on Mammalian Nephrons.
Abstract
This report deals with the development of a study to determine the effect of antidiuretic hormone (ADH) on kidney salt and water absorption utilizing the stop-flow technique to localize which areas of the nephron were affected by ADH and also how unidirectional Na and H2O fluxes across the nephron were altered in order to study the mechanisms of ADH action. Following the conclusion of these experiments and based on the results, the research was broadened to include the mechanisms of action of other hormones or drugs or neurotransmitters on kidney and gut salt and water absorption and in particular whether these agents act through direct cellular effects or through physical forces exerted through the cardiovascular system. There are two basic mechanisms by which salt, water and small organic solutes cross epithelial tissues, such as the gut and kidney, from the lumen into the blood. One mechanism is by transcellular transport across the luminal mucosal or apical cell membrane and then through the basolateral or serosal cell membrane. Solutes are transported by membrane carrier molecule pumps which transport the solutes by facilitated or active transport. A second mechanism by which many of the same solutes cross the membrane is through passive, paracellular movement through the tight junctions and the lateral intercellular spaces between the epithelial cells. Peptide hormones can directly affect transcellular movement by binding to the cell membranes at receptor sites and modulating intracellular events which increase or decrease pump activity. These same hormones could have cardiovascular effects which modify transcellular pumping by altering the delivery of O2 to the cells for support of transport energy requirements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1979
- Accession Number
- ADA102037
Entities
People
- David Mailman
Organizations
- University of Houston