Ontogeny of angiotensin II type 2 (AT2) receptor mRNA in the rat.

To study the distribution of the recently cloned angiotensin II type 2 (AT2) receptor in the rat fetus, a double stranded cDNA was generated by a new and recently described methodology requiring no cloning procedure. The cDNA obtained after reverse transcription (RT) and polymerase chain reaction (PCR) amplification corresponded to 500 base pairs of the gene coding sequence, and included the SP6 and T7 promoters at the 5' and 3' end, respectively. 35S-labeled cRNA sense and antisense probes were synthesized by in vitro transcription and used for in situ hybridization.

Ontogeny of the two angiotensin II type 1 receptor subtypes in rats.

The two subtypes (AT1A and AT1B) of the type 1 (AT1) angiotensin II receptor mRNA were localized by in situ hybridization in rat fetal tissues from day 11 to 19 of gestation and in the young rat from day 0 to 10 postpartum, by use of 35S-labeled cRNA probes. Both subtype mRNAs were present in the kidney and in the adrenal gland. Organs such as liver, lung, heart, and undifferentiated mesenchymes expressed only AT1A mRNA.

Tissue-specific expression of type 1 angiotensin II receptor subtypes. An in situ hybridization study.

The angiotensin II type 1 (AT1) receptor in murine species exists as two isoforms (AT1A and AT1B) encoded by two different genes. Both subtypes have a 9/10 homology in the coding sequence of their mRNA. We examined organs of adult rats (liver, pituitary gland, adrenal gland, kidney, heart, and lung) to study the differential expression of these two genes in target tissues for angiotensin II.

Distribution of type 1 angiotensin II receptor subtype messenger RNAs in the rat fetus.

The localization of the two type 1 angiotensin II receptor subtype (AT1A and AT1B) messenger RNAs in the 19-day-old rat fetus was studied by in situ hybridization. AT1 receptor mRNAs were detected in target organs of the renin-angiotensin system such as the kidney, adrenal gland, liver, heart, large arteries, and pituitary gland. In addition, angiotensin II receptors were present in specialized mesenchymal cells surrounding the cartilage, in the pericardium, in the lung, and in the undifferentiated mesenchymal tissue.