Prorenin Secretion From Human Testis: No Evidence for Secretion of Active Renin or Angiotensinogen*

Abstract

To determine if the testis secretes active renin and prorenin, we collected internal spermatic venous blood from 29 young men undergoing varicocelectomy and measured plasma prorenin and active renin together with angiotensinogen and testosterone. Prorenin was higher in internal spermatic venous plasma than in peripheral plasma (+5.3 +/- 1.2 (+/- SE) ng/mL.h [+1.21 ng/(L.s)]; P less than 0.001) as was testosterone [+344 +/- 32 ng/mL [(+1193 nmol/L; P less than 0.001], but there was no significant difference in either active renin (-0.74 +/- 0.45 ng/mL.h [-0.17 ng/(L.s)] or angiotensinogen [+12 +/- 24 ng/mL (+0.01 mumol/L)]. These results demonstrate that the testis secretes prorenin, but not active renin or angiotensinogen, into the general circulation. They support the hypothesis that extrarenal renin systems cannot process prorenin to renin.

High-affinity prorenin binding to cardiac man-6-P/IGF-II receptors precedes proteolytic activation to renin

“…Finally, our results are not limited to recombinant human prorenin but also apply to native human plasma prorenin. Plasma prorenin is predominantly of renal origin (11), although extrarenal prorenin sources such as the eye (12), ovary (20), placenta (33), and testis (54) are also known to contribute to circulating levels of prorenin. When incubated at 37°C for 4 h with plasma containing prorenin (and low levels of renin), myocytes were found to contain predominantly renin.…”

Renin, Prorenin and the Putative (Pro)renin Receptor

“…50 Local prorenin synthesis does appear to occur in adrenal, eye, ovaries, and testis. 7,33,51,52 This explains why prorenin is still present in plasma of nephrectomized subjects (Figure 1). 53 An attractive concept is that in tissues not synthesizing renin locally, circulating prorenin, after its local activation, contributes to angiotensin generation.…”

Biochemical, Structural and Pathophysiological Aspects of Prorenin and (Pro)renin Receptor

“…Prorenin (45-47 kDa containing 406 amino acid residues), the pre-active form of renin, is predominantly synthesized by granular cells of the juxtaglomerular apparatus (JGA) in the terminal afferent arteriole (Schnermann & Briggs, 2008;Schweda et al, 2007) and principle cells of the collecting ducts (Prieto-Carrasquero et al, 2004;Rohrwasser et al, 1999;Kang et al, 2008). Prorenin is also synthesized in many other tissues like adrenal glands (Ganten et al, 1974(Ganten et al, , 1976Ho and Vinson, 1998), zona glomerulosa (Doi et al, 1984;Brecher et al, 1989), eye, Müller cells, mast cells (Krop et al, 2008), ovarian follicular fluid (Glorioso et al, 1986), and theca cells (Do et al, 1988), uterus (Derkx et al, 1987;Itskovitz et al, 1987), myometrium/decidual cells (Shaw et al, 1989), placenta (Lenz et al, 1991), chorionic cells, testis and leydig cells (Sealey et al, 1988). The submandibular gland in some mice strains produces a large amount of renin, which is a product of the Ren-2 renin gene distinct from the renal renin gene, Ren-1 (Cohen et al, 1972;Wilson et al, 1981;Holm et al, 1984) and this action is mediated by prorenin converting enzyme present in submandibular gland of the same mice strains (Kim et al, 1991).…”