Journal ArticleDOI
Distribution of hormone-dependent adenylate cyclase in the nephron and its physiological significance.
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TLDR
There is good evidence that hormone-dependent adenylate cyclase is involved in the cell mechanisms through which many hormones regulate tubular functions, and the nature of the hormonal effect induced via cAMP is not yet established.Abstract:
In addition to the well established action of PTH in proximal tubules and of AVP in collecting tubules, polypeptide hormones were recently shown to regulate transport properties in other tubular portions. Although still scarce, such physiological studies using isolated perfused tubules demonstrated hormonal effects in those nephron segments observed to contain responsive adenylate cyclase and not in the others. Moreover, the same effects were elicited by applying exogenous cAMP or cAMP derivatives. There is, therefore, good evidence that hormone-dependent adenylate cyclase is involved in the cell mechanisms through which many hormones regulate tubular functions. The effects obtained varied depending on the segment of tubule used. It is not yet established whether the nature of the hormonal effect induced via cAMP is entirely specified by the responding cell types or is also specified by the hormone itself. Further studies are needed to clarify this important problem, as well as many other as yet unsolved questions. There is obviously much more to learn about the hormonal regulation of tubular cell functions by using appropriate biochemical and physiological micromethods.read more
Citations
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Cyclic-3',5'-nucleotide phosphodiesterase isozymes in cell biology and pathophysiology of the kidney.
TL;DR: Evidence indicates that PDE isozymes play a role in several pathobiologic processes in kidney cells, and are a target for action of numerous novel selective PDE inhibitors, which are key components in the design of novel "signal transduction" pharmacotherapies of kidney diseases.
Journal ArticleDOI
Receptors for PTH and pTHrP: their biological importance and functional properties
TL;DR: A detailed exploration of the receptor-ligand interaction process is currently being pursued through the use of site-directed mutagenesis and photoaffinity cross-linking methods, which could enable the development of novel PTH receptor ligands that have therapeutic value in treating diseases such as osteoporosis and certain forms of hypercalcemia.
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Pathophysiology of bone loss in patients receiving anticonvulsant therapy.
TL;DR: An understanding of bone biology and the pathophysiology of bone loss can aid in the identification and monitoring of patients at risk and in the planning of appropriate prophylactic and therapeutic measures, by which most of the morbidity associated with AED-inducedBone loss can be prevented.
References
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Journal ArticleDOI
Sodium chloride, urea, and water transport in the thin ascending limb of Henle. Generation of osmotic gradients by passive diffusion of solutes.
TL;DR: It is concluded that active transport of salt by the t ALH was not detected by the experimental protocol of the current studies, and that the unique membrane characteristics of tALH allows for generation of osmotic gradients on purely passive mechanisms when perfused with isosmolal salt solutions in a bath with appropriate salt and urea concentrations.
Journal ArticleDOI
Effect of vasopressin on electrical potential difference and chloride transport in mouse medullary thick ascending limb of Henle's loop.
Dennis A. Hall,Dawn M. Varney +1 more
TL;DR: AVP has a second site of action in the kidney to increase chloride transport by the medullary thick ascending limb in addition to its well-known effect on the water permeability of the collecting tubule, which would contribute to urinary concentrating ability by increasing the axial osmotic gradient in the renal medulla.
Journal ArticleDOI
Renal Nerves and Sodium Excretion
TL;DR: The prevailing view among renal physiologists has been that the renal nerves have no important role in the regulation of renal excretory function under normal conditions, but more recent experimental studies challenge this view.
Journal ArticleDOI
A functional comparison of the cortical collecting tubule and the distal convoluted tubule.
J B Gross,M Imai,J P Kokko +2 more
TL;DR: Both segments of rabbit tubules are similar in that each possesses an electrogenic transport process but that these segments differ in that the CCT requires either exogenous or endogenous mineralocorticoid to maintain a maximal negative PD, whereas the PD in the DCT appears to be independent of mineraloc Corticoid effect.
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