Cryorenin in the newborn human and lamb.
Renin and big renin (cryorenin) were measured in the plasma of 78 babies at birth, and studied in six newborn lambs 2-3 weeks of age in response to angiotensin II (0.25 microgram/kg per min) infusion. There were (mean +/- S.E.M.) 15.9 +/- 2.0 ng/ml per h of renin and 11.1 +/- 2.3 of cryorenin, measured as plasma renin activity (PRA) in newborn cord blood. Cryorenin and renin decreased in parallel in the newborn lamb from 19 +/- 2.3 ng/ml per h and 28.6 +/- 2.7 to 6.5 +/- 1.8 (P less than 0.001) and 15.9 +/- 1.8 (P less than 0.01), respectively after 30 min of the angiotensin II infusion. Mean aortic blood pressure increased 30 mm Hg. These data suggest that cryorenin levels are high in the newborn lamb and human, and that both cryorenin and renin are under angiotensin II control in the newborn lamb.
D000804:Angiotensin II / Q000097:blood; D000818:Animals; D004792:Enzyme Precursors / Q000097:blood*; D005312:Fetal Blood / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007231:Infant, Newborn; D012083:Renin / Q000097:blood*; D012756:Sheep / Q000097:blood*
D004792:Enzyme Precursors; D000804:Angiotensin II; D012083:Renin