Renin immunohistochemistry in the mesonephros and metanephros of the pig embryo

Abstract

The occurrence and distribution of renin was investigated in meso- and metanephric kidneys of pig embryos in various gestational stages. The immunohistochemical peroxidase-antiperoxidase-method (PAP) was used on paraffin sections after application of an antiserum against mouse renin which cross reacts with pig renin. Renin immunoreactivity was already found in the mesonephros of 21 day pig embryos (crown-rump(CR)-length 12 mm) with the strongest reaction in the media of the juxtaglomerular afferent arteriole. Efferent vessels, mesonephric arteries, and the aortic wall also contained scattered renin-positive cells. In the definitive kidney, renin was not detected prior to the 25 mm CR-length-stage. In 45 mm embryos, immunocytochemical staining was observed not only in the media of kidney arteries and arterioles, but also in proximal tubules after pinocytic absorption of filtered renin. TEM-studies revealed that the media of both the mesonephric and the developing metanephric arteries and arterioles contains epithelioid cells whose ultrastructure is very similar to that of renin-producing cells in the adult organ. The observed distribution of renin-producing cells along the entire renal arterial tree points to the possibility that the major function of the renin-angiotensin system in the fetal animal is to participate in the stabilization of renal perfusion pressure.

Renin release and gene expression in intact rat kidney microvessels and single cells.

“…Similar developmental changes in immunoreactive renin distribution have been demonstrated in the mouse (2), pig (3), and human embryo (4). Using in situ hybridization histochemistry and renin immunocytochemistry, we have demonstrated that renin is synthesized and stored in widespread renal vascular segments during maturation (5).…”

Role of blood pressure in mediating the influence of salt intake on renin expression in the kidney

“…The best documented among these is the perfusion pressure of the preglomerular arteriolar tree (12,20,36), which falls from the renal arterial pressure down to the glomerular pressure mainly along the interlobular arteries and afferent arterioles. It has been hypothesized that the increasing blood pressure in the developing kidney is a major factor causing the characteristic developmental shift of renin expression from larger vessels to the end of afferent arterioles (6,10). The unique position of renin-producing cells in the adult kidney may be due to the fact that the intraluminal pressure at the juxtaglomerular pole of afferent arterioles is lowest within the preglomerular vasculature.…”

The Intrarenal Renin-Angiotensin System: From Physiology to the Pathobiology of Hypertension and Kidney Disease

“…Expression of angiotensinogen, renin, ACE, and AT1/ AT2 receptors has been demonstrated in mesonephrons (Egerer et al, 1984;Celio et al, 1985;Wintour et al, 1996). Additionally, developing metanephrons express all components of the RAS (Gomez et al, 1989;Yosipiv et al, 1994;Yosipiv and El-Dahr, 1996;Norwood et al, 1997;Prieto et al, 2001).…”