title: Concentration and molecular forms of active and inactive renin in human fetal kidney, amniotic fluid and adrenal gland: evidence for renin-angiotensin system hyperactivity in 2nd trimester of pregnancy.
abstract: In a study of 38 fetuses total kidney renin was significantly correlated with gestational age (r = 0.63). Although whole fetal kidney renin specific activity was found to decrease with gestational age (r = -0.65), the mean value of the specific activity was about 20 times greater than in normal adult cortex and double that in tissue from patients with renal artery stenosis, suggesting renin-angiotensin system hyperactivity. In approximately 40% of fetal kidneys examined, evidence for an inactive (trypsin-activatable) renin precursor was found. The molecular weight of this form was indistinguishable from active renin (45 000 daltons) by Sephadex chromatography. Amniotic fluid from nine cases (100%) contained angiotensin (ANG) 1, angiotensin converting enzyme (ACE), renin substrate, active and inactive renin (both 45 000 daltons). Five of the 38 (13%) fetal adrenal glands contained renin, but no evidence for trypsin-activatable forms. Aldosterone was present in low concentration in the earliest adrenals examined, and a positive correlation existed between total tissue aldosterone and gestational age (r = 0.73). These findings suggest that the fetal renin-angiotensin system has an important role to play in the maintenance of extracellular fluid volume and blood pressure in the developing fetus.
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism; D000450:Aldosterone / Q000378:metabolism; D000653:Amniotic Fluid / Q000378:metabolism; D000803:Angiotensin I / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005333:Fetus / Q000378:metabolism* / Q000648:ultrastructure; D005865:Gestational Age; D006801:Humans; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism; D011247:Pregnancy; D012083:Renin / Q000378:metabolism*; D012084:Renin-Angiotensin System; D014357:Trypsin / Q000494:pharmacology
chemical_list: D000450:Aldosterone; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; D014357:Trypsin; D012083:Renin