Decrease in Gs protein expression may impair adenylate cyclase activation in old kidneys

C. T. Liang, J. Barnes, H. Hanai, M. A. Levine

Research output: Contribution to journalArticlepeer-review

Abstract

The possibility that alteration in stimulatory guanine nucleotide-binding protein (Gs) expression may contribute to the blunting of renal parathyroid hormone (PTH)-stimulated adenylate cyclase in aged rats was examined. Using rat cDNA probe, we identified a Gs α-subunit (Gsα) of 1.9 kb. Age did not alter the size of Gsα mRNA. The level of Gsα mRNA [normalized to poly(A)+ RNA] was decreased 23%, which was consistent with our previous report that Gsα protein decreased in senescence. In contrast, mRNA level of Giα2 increased with age. Level of β-actin mRNA did not change with age. Nuclear runoff assay was performed to determine the transcription rate of Gs mRNA. Synthesis of poly(A)+ RNA and total RNA was reduced 39% and 37%, respectively, in nuclei prepared from old kidney, which suggested a general decline in RNA synthesis capacity in old rats. Our results also showed the transcription rate of Gsα mRNA in aged rats was reduced 89%, a decrease far exceeding that observed for total RNA or poly(A)+ RNA. We concluded that the decrease in steady-state level of Gsα mRNA was specific and probably was due to a reduction in the transcription activity. Thus alteration in Gs transcription may contribute, at least in part, to the impaired renal adenylate cyclase activation in aged rats.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Fluid and Electrolyte Physiology
Volume264
Issue number5 33-5
StatePublished - May 1993
Externally publishedYes

Keywords

  • Forskolin
  • G proteins
  • Messenger ribonucleic acid
  • Parathyroid hormone

ASJC Scopus subject areas

  • Physiology
  • Medicine(all)

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