Plasma soluble (pro)renin receptor is independent of plasma renin, prorenin, and aldosterone concentrations but is affected by ethnicity.

A soluble (pro)renin receptor (sPRR) circulates in plasma and is able to bind renin and prorenin. It is not known whether plasma sPRR concentrations vary with the activity of the renin-angiotensin system. We measured plasma sPRR, renin, prorenin, and aldosterone concentrations in 121 white and 9 black healthy subjects, 40 patients with diabetes mellitus, 41 hypertensive patients with or without renin-angiotensin system blockers, 9 patients with primary aldosteronism, and 10 patients with Gitelman syndrome. Median physiological plasma sPRR concentration was 23.5 ng/mL (interquartile range, 20.9-26.5) under usual uncontrolled sodium diet. sPRR concentration in healthy subjects, unlike renin and prorenin, did not display circadian variation or dependence on age, sex, posture, or hormonal status. sPRR concentrations were ≈25% lower in black than in white subjects, whereas renin concentrations were ≈40% lower. Patients with diabetes mellitus (average renin-high prorenin levels) and with hypertension only (average renin-average prorenin levels) had sPRR concentrations similar to healthy subjects. Renin-angiotensin system blockade was associated with increase of sPRR concentration by ≈12%. sPRR in patients with primary aldosteronism (low renin-low prorenin) and Gitelman syndrome (high renin-high prorenin) were similar and ≈10% higher than in healthy subjects. There was no correlation between sPRR and renin or prorenin. In conclusion, our results show that plasma sPRR concentrations are dependent on ethnicity and independent of renin, prorenin, and aldosterone concentrations in healthy subjects and in patients with contrasted degrees of renin-angiotensin system activity.

Morphological study of the spinal motoneurons controlling the urethral sphincter of female rats: role of androgens in a menopausal model.

PURPOSE: In this study in a menopausal rat model we describe the effect of androgen withdrawal on motoneurons innervating 2 muscles involved in female urinary continence, namely the intrinsic urethral sphincter and the pubococcygeus muscle. MATERIALS AND METHODS: The 5 groups studied were 2 ovariectomized groups and their sham operated controls plus 1 ovariectomized group with dihydrotestosterone supplementation. Blood testosterone assays were performed. Androgen receptor immunohistochemistry was performed on spinal cord sections, in which specific motoneuron subpopulations were identified. Maximal somal cross-sectional area was compared among the groups. RESULTS: Differences in somal cross-sectional area of motoneurons innervating the pubococcygeus muscle were observed after ovariectomy. Androgen receptor immunopositive nuclei staining disappeared, in line with undetectable blood testosterone levels. DISCUSSION: The modifications of androgen receptor expression and somal morphological appearance in the pudendal motoneurons controlling the external urethral sphincter of ovariectomized female rats suggests that testosterone probably influences neurotransmission and coordination of urinary continence at the spinal level.