title: Acute effect of whey peptides upon blood pressure of hypertensive rats, and relationship with their angiotensin-converting enzyme inhibitory activity.
abstract: METHODS
  The aim of this study was to investigate the antihypertensive effect of a peptide fraction (PepC) obtained from a whey protein concentrate following hydrolysis by Cynara cardunculus, as well as of its fraction with MW below 3 kDa (PepCF). Both these concentrates encompassed peptides that exhibited potent in vitro inhibition of angiotensin-converting enzyme (ACE): two were released from α-lactalbumin--KGYGGVSLPEW and DKVGINYW, and one from β-lactoglobulin--DAQSAPLRVY.
  
  
  RESULTS
  Upon oral administration, by gastric intubation, of 400 mg/kg body weight (bw) of those peptide concentrates, or 5 mg/kg bw of the corresponding synthetic peptides, to 12 wk-old spontaneously hypertensive rats (SHR), the systolic and diastolic blood pressures were monitored by the tail-cuff method--before, and 2, 4, 6, 8 and 24 h afterwards. Water and zofenopril (5 mg/kg bw)--a known ACE-inhibitor, were used as negative and positive controls, respectively. Acute administration of PepC, PepCF, KGYGGVSLPEW, DKVGINYW and DAQSAPLRVY caused antihypertensive effects in SHR; the maximum effect occurred by 4 h and 6 h after administration of the peptide concentrates and the synthetic peptides, respectively. PepC and KGYGGVSLPEW also showed ACE-inhibitory activity in vivo: the pressor effect of angiotensin I was significantly lower, and the response to bradykinin increased when the rats were pre-treated with either product.
  
  
  CONCLUSIONS
  Our results strongly suggest that PepC will be effective as nutraceutical ingredient for the formulation of functional foods aimed at hypertension control.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Tânia
authors.initials: T
authors.lastname: Tavares
authors.forename: María-Ángeles
authors.initials: MÁ
authors.lastname: Sevilla
authors.forename: María-José
authors.initials: MJ
authors.lastname: Montero
authors.forename: Rosalía
authors.initials: R
authors.lastname: Carrón
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Malcata
mesh_terms: D000284:Administration, Oral; D000803:Angiotensin I / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D001920:Bradykinin / Q000494:pharmacology; D007768:Lactalbumin / Q000737:chemistry; D007782:Lactoglobulins / Q000737:chemistry; D008297:Male; D008894:Milk Proteins / Q000737:chemistry*; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D000067816:Whey Proteins
chemical_list: D000959:Antihypertensive Agents; D007782:Lactoglobulins; D008894:Milk Proteins; D010446:Peptide Fragments; D010455:Peptides; D000067816:Whey Proteins; D007768:Lactalbumin; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; D001920:Bradykinin