Renin-Substrat-(Angiotensinogen-)Konzentration im maternen und fetalen Blut

Zusammenfassung Bei 18 Schwangeren wurden unter der Geburt Vergleichsbestimmungen der Angiotensinogen-Konzentration und der Renin-Aktivität (modifiz. Methode nach Kaneko) im mütterlichen peripher-venösen und Nabelschnurblut durchgeführt.Im fetalen Serum ist die Angiotensinogen-Konzentration auf durchschnittlich 1440 ± 543 ng/ml gegenüber 3622 ± 1312 ng/ml im mütterlichen Serum (p<0,001) herabgesetzt. Dagegen liegt der fetale Angiotensinogengehalt, bezogen auf die Erwachsenen-Werte Nichtgravider (1115 ± 178 ng/ml) um 39% (p<0,05) erhöht.Die Renin-Aktivität ist im mütterlichen Serum mit 15,7 ± 8,7 ng/ml/4 Std signifikant (p<0,05) gegenüber dem fetalen Blut (31,4 ± 28,2 ng/ml/4 Std) herabgesetzt.Es wird geschlossen, daß die fetale Leber in hohem Maße Angiotensinogen synthetisieren kann. Der mögliche stimulierende Einfluß mütterlicher oder placentarer Oestrogene auf die hepatische Biosynthese wird erörtert. Unter Berücksichtigung des Konzentrationsgradienten ist mit einem placentaren Übertritt von Angiotensinogen zur fetalen Seite nur in geringem Maße zu rechnen.     

Effects of n-butylparaben on steroidogenesis and spermatogenesis through changed E2 levels in male rat offspring

Parabens are widely used as antibacterial agents, which are concerned recently in the relationship between the use of parabens and reproductive toxicity. So that reassessment of the risk of parabens is needed. In this study, one of parabens, n-butylparaben (n-BP) was orally administered to pregnant Wistar rats (0, 64, 160, 400 and 1000 mg/kg/day) from gestation day (GD) 7 through postnatal day (PND) 21. Reduced anogenital distance (AGD) and delayed preputial separation (PPS) were observed in the male offspring. The weights of the testes were significantly reduced at PND 21–90. The weights of the epididymides were significantly reduced at all monitoring points, except PND 35. Seminal vesicle weights were significantly reduced on PND 21. Serum testosterone (T) was significantly decreased, especially on PND 49. The levels of 17β-estradiol (E₂) showed an increase at each of the tested points except on PND 180. Serum luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels in the n-BP treated groups were lower on PND 21, 35 and 49 but elevated on PND 90 compared to control levels. n-BP reduced epididymal cauda sperm counts and daily sperm production in a dose-dependent manner; this difference was statistically significant at exposure groups of 400 and 1000 mg/kg/day. The present study strongly suggests that exposure to n-BP in utero and during lactation has adverse effects on the reproductive system in male offspring, with a no observed adverse effect level (NOAEL) of 160 mg/kg/day. To our knowledge, this is the first study that reports increased E₂ levels of male rats following n-BP exposure; we suggest that E₂ levels may be considered as biomarkers for some endocrine disrupting chemicals (EDCs).