Organ-specific overexpression of renal LAT2 and enhanced tubular L-DOPA uptake precede the onset of hypertension

• Type: Article in International Scientific Journal
• Date: 2003

Authors

Maria João Pinho (Author) FMUP; Pedro Gomes (Author) FMUP; Maria Paula Serrão (Author) FMUP; Maria João Bonifácio (Author) Other; Patrício Soares da Silva (Author) FMUP

Journal

Title: Hypertension

Vol. 42

Pages: 613-618

ISSN: 0194-911X

Publisher: Wolters Kluwer Health

Indexing

ISI Web of Knowledge - 22 Citations

Scopus - 21 Citations

Pubmed / Medline

Scientific classification

FOS: Medical and Health sciences > Basic medicine

CORDIS: Health sciences > Medical sciences > Medicine > Physiology

Other information

Authenticus ID: P-000-EZ9

DOI: 10.1161/01.hyp.0000091822.00166.b1

Abstract (EN): Spontaneously hypertensive rats (SHR) might have increased renal production of dopamine. L-3,4-Dihydroxyphenylalanine (L-DOPA) uptake in renal epithelial cells is promoted through the type 2 L-type amino acid transporter (LAT2), and this might rate-limit the synthesis of renal dopamine. The present study evaluated L-DOPA uptake in isolated renal proximal tubules of SHR and normotensive controls (Wistar-Kyoto rats [WKY]). Expression of LAT1 and LAT2 in the renal cortex and intestinal mucosa was also evaluated. Tubular uptake of L-DOPA in WKY and SHR was a saturable process, being greater in the latter than the former at both 4 and 12 weeks of age. cDNA fragments (LAT1, 688 bp; LAT2, 729 bp) labeled with P-32 were used as probes for Northern blot analysis. Expression of LAT2 in SHR kidneys was higher than in WKY kidneys. This increase was more marked at 4 than at 12 weeks of age. Intestinal LAT2 expression, however, was identical in SHR and WKY at both 4 and 12 week of age. By Northern blot analysis, the LAT1 transcript was not identified in either the kidney or intestine. Kidney total RNA was then reverse-transcribed and amplified by polymerase chain reaction with specific primers for LAT1. The presence of a fragment of the expected size for LAT1 led to the conclusion that LAT1 mRNA is a rare message in kidney. We conclude that overexpression of LAT2 in the SHR kidney might contribute to the enhanced L-DOPA uptake, which is organ specific and precedes the onset of hypertension.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6