Unknown

Dataset Information

0

Angiotensin receptors from rat liver, brain and pituitary gland. Expression of two subtypes in Xenopus oocytes.


ABSTRACT: Xenopus laevis oocytes were used to express angiotensin receptors encoded by mRNAs extracted from rat liver, adenohypophysis and brain. Groups of ten mRNA-injected oocytes were loaded with 45Ca2+ and the responsiveness to angiotensin II (A II) and related molecules tested by monitoring 45Ca2+ outflux. A II and angiotensin III (A III) induced a marked and transient increase in 45Ca2+ outflux from mRNA, but not from control, water-injected, oocytes. The increase over basal value of 45Ca2+ outflux during a 5 min application period of A II or A III was used as a response index. Observed responses were of high magnitude, reproducible and dose-dependent. For these reasons, mRNA-injected oocytes constitute a valuable system for investigating the pharmacological properties of angiotensin receptors from tissues of different origin under experimental conditions which eliminate tissue-specific interference which might be encountered in classical binding studies on acellular preparations. We demonstrate a fairly good parallelism between the relative potencies of A I, A II and A III in eliciting an increase in 45Ca2+ outflux from liver and adenohypophyseal mRNA-injected oocytes and the relative affinities of these peptides for binding to liver or adenohypophyseal membranes (A II greater than A III much greater than A I). The predominant receptor subtype expressed by brain mRNA discriminated very poorly between A II and A III, whereas angiotensin receptors expressed by liver or adenohypophyseal mRNA discriminated between AII and AIII very efficiently.

SUBMITTER: Cantau B 

PROVIDER: S-EPMC1151305 | biostudies-other | 1991 Aug

REPOSITORIES: biostudies-other

Similar Datasets

| S-EPMC547850 | biostudies-other
| S-EPMC7040196 | biostudies-literature
| S-EPMC549013 | biostudies-literature
| S-EPMC2860192 | biostudies-other
| S-EPMC3614054 | biostudies-literature
| S-EPMC2747220 | biostudies-literature
| S-EPMC1573006 | biostudies-literature
| S-EPMC1130694 | biostudies-other
| S-EPMC7732776 | biostudies-literature
| S-EPMC6481336 | biostudies-literature