The purpose of this study was to assess the possibility of isolating biologically active peptides from human blood using large volumes of blood filtrate, which are available from patients undergoing extracorporeal ultrafiltration because of renal insufficiency. This filtrate was submitted to six chromatographic separation steps, yielding one purified peptide which was completely analysed in its primary structure. It was found to be strikingly similar to proteins, described initially as rabbit uteroglobin (or blastokinin) and, more recently, from human bronchial lavage as the '10 kDa Clare cell protein', as well as from human urine as 'protein-1'. The natural molecule contains two chains of identical amino acid sequences of 70 residues which are arranged as an antiparallel dimer due to the disulphide bonds between two cysteines at positions 3 and 69. Mass analysis of the molecular forms yielded molecular weights from 15827 Da (non-oxidized form) to 15859 Da (bi-oxidized form). We conclude that this peptide isolated from the filtrate represents the human uteroglobin, and we demonstrate for the first time that this peptide may be involved as a humoral factor in reproductive or other physiological functions.

The purpose of this study was to assess the possibility of isolating biologically active peptides from human blood using large volumes of blood filtrate, which are available from patients undergoing extracorporeal ultrafiltration because of renal insufficiency. This filtrate was submitted to six chromatographic separation steps, yielding one purified peptide which was completely analysed in its primary structure. It was found to be strikingly similar to proteins, described initially as rabbit uteroglobin (or blastokinin) and, more recently, from human bronchial lavage as the ‘10 kDa Clara cell protein’, as well as from human urine as ‘protein-1’. The natural molecule contains two chains of identical amino acid sequences of 70 residues which are arranged as an antiparallel dimer due to the disulphide bonds between two cysteines at positions 3 and 69. Mass analysis of the molecular forms yielded molecular weights from 15 827 Da (non-oxidized form) to 15 859 Da (bi-oxidized form). We conclude that this peptide isolated from the filtrate represents the human uteroglobin, and we demonstrate for the first time that this peptide may be involved as a humoral factor in reproductive or other physiological functions.

4To whom correspondence should be addressed The purpose of this study was to assess the possibility of isolating biologically active peptides from human blood using large volumes of blood filtrate, which are available from patients undergoing extracorporeal urtrafirtration because of renal insufficiency. This filtrate was submitted to six chromatographic separation steps, yielding one purified peptide which was completely analysed in its primary structure. It was found to be strikingly similar to proteins, described initially as rabbit uteroglobin (or blastokinin) and, more recently, from human bronchial lavage as the '10 kDa Clara cell protein', as well as from human urine as 'protein-1'. The natural molecule contains two chains of identical amino acid sequences of 70 residues which are arranged as an antiparallel dimer due to the disulphide bonds between two cysteines at positions 3 and 69. Mass analysis of the molecular forms yielded molecular weights from 15 827 Da (non-oxidized form) to 15 859 Da (bi-oxidized form). We conclude that this peptide isolated from the filtrate represents the human uteroglobin, and we demonstrate for the first time that this peptide may be involved as a humoral factor in reproductive or other physiological functions.

The contractile action of bradykinin on isolated smooth muscles is known to be potentiated by special peptides isolated from snake venoms and other animal sources. A fraction F (AppF) has been derived from Agkistrodon piscivorus piscivorus venom. This fraction does not increase the depressor effect of bradykinin on blood pressure, potentiates the action of bradykinin on isolated guinea-pig ileum and prolongs the duration of relaxation in isolated rat duodenum. This fraction was able to inhibit the conversion of angiotensin I to angiotensin II in vitro. The primary structure of this decapeptide is given.