Identification of the site of glucocorticoid action on neutral amino acid transport in superficial nephrons of rat kidney (original) (raw)

Summary.

Glucocorticoid hormones enhance the reabsorptive capacity of filtered amino acids in rat kidney, as it was shown in previous in vivo clearance experiments. In the present study, the site of glucocorticoid action on neutral amino acid transport in superficial nephrons of rat kidney was investigated using in vivo micropuncture technique. Adult female Wistar rats were treated with dexamethasone (DEX), and fractional excretion of L-glutamine (L-Gln) and L-leucine (L-Leu) were determined and related to inulin after microinfusion into different nephron segments. DEX reduced fractional excretion of both neutral amino acids as a sign of enhanced reabsorptive capacity. The site of main DEX action on L-Leu reabsorption has been localized in the proximal straight tubule. However, in the case of L-Gln, the inhibition of _γ_-glutamyltranspeptidase (_γ_-GT) by administration of acivicin indicated the importance of this brush border enzyme in reduced L-Gln excretion. DEX enhanced _γ_-GT activity by tubular acidification. It can be presumed a DEX-inducible transport system for neutral amino acids mainly localized in proximal straight tubules of rat kidney.

Access this article

Log in via an institution

Subscribe and save

• Starting from 10 chapters or articles per month
• Access and download chapters and articles from more than 300k books and 2,500 journals
• Cancel anytime View plans

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Author information

Authors and Affiliations

1. Institute of Pharmacology and Toxicology, Friedrich Schiller University of Jena, Federal Republic of Germany, , , , , , DE
   M. Schwertfeger & C. Fleck
2. Institute of Clinical Chemistry, Friedrich Schiller University of Jena, Federal Republic of Germany, , , , , , DE
   M. Roskos

Authors

1. M. Schwertfeger
2. M. Roskos
3. C. Fleck

Additional information

Received July 8, 1999

Rights and permissions

About this article

Cite this article

Schwertfeger, M., Roskos, M. & Fleck, C. Identification of the site of glucocorticoid action on neutral amino acid transport in superficial nephrons of rat kidney.Amino Acids 18, 279–288 (2000). https://doi.org/10.1007/s007260050024

Download citation

• Issue date: May 2000
• DOI: https://doi.org/10.1007/s007260050024