216
M.A. Masini et al.
ANP-like materials in the cardiocytes of several species of fish, and the
immunohistochemical controls used support the specificity of the
immunostaining. It would thus appear that the fish heart produces
substances quite similar to mammalian ANP.
An eel atrial peptide with 27 amino acid residues has been purified and
sequenced; this ANP, when injected into rats, was natriuretic, diuretic and
vasorelaxant [21]. The eel peptide is structurally similar to the mammalian
ANPs; it has an intramolecular ring structure with 17 amino acid residues
formed by a disulfide bond. The identical sequences conserved in all ANPs
so far identified are also conserved in this peptide except for four amino
acid substitutions (Fig. 1).
141
142
143
(117) (118) (119)
SerGly- Leu142
143
144
132
133
(108) (109)
144
145
(120) (121)
GlyCys
145
146
a
b
c
135
(111 )
Fig. 1. Amino acid sequences of: rat a-ANP (a), human ANP (b) and eel ANP (c).
The immunodetection of ir-ANP-like substances with mammalian ANP
antibodies may be therefore performed in teleostean fish, but obviously the
physiological responses, after administration of a heterologous ANP, are
open to questions. The molecular structure of Antarctic teleost ANP
probably differs from that of mammals and perhaps is more closely related
to eel ANP. Antarctic fish ANP has not yet been sequenced, but if it is
presumed similar to the eel ANP there is a strong homology with the amammalian ANP.
ANP in Heart Extracts and Plasma of Antarctic Teleosts
ANP radioimmunoassay of heart homogenates and plasma were performed
in Chionodraco hamatus and Trematomus bernacchii, using standard
protocols (RIA, Peninsula Lab. Belmomt, CA) and antibodies to a-rANP
(99-126) [22]. The levels of ANP-like peptides in plasma and heart of
Chionodraco were twice the corresponding values in Trematomus (Fig. 2).
M.A. Masini et al.
ANP-like materials in the cardiocytes of several species of fish, and the
immunohistochemical controls used support the specificity of the
immunostaining. It would thus appear that the fish heart produces
substances quite similar to mammalian ANP.
An eel atrial peptide with 27 amino acid residues has been purified and
sequenced; this ANP, when injected into rats, was natriuretic, diuretic and
vasorelaxant [21]. The eel peptide is structurally similar to the mammalian
ANPs; it has an intramolecular ring structure with 17 amino acid residues
formed by a disulfide bond. The identical sequences conserved in all ANPs
so far identified are also conserved in this peptide except for four amino
acid substitutions (Fig. 1).
141
142
143
(117) (118) (119)
SerGly- Leu142
143
144
132
133
(108) (109)
144
145
(120) (121)
GlyCys
145
146
a
b
c
135
(111 )
Fig. 1. Amino acid sequences of: rat a-ANP (a), human ANP (b) and eel ANP (c).
The immunodetection of ir-ANP-like substances with mammalian ANP
antibodies may be therefore performed in teleostean fish, but obviously the
physiological responses, after administration of a heterologous ANP, are
open to questions. The molecular structure of Antarctic teleost ANP
probably differs from that of mammals and perhaps is more closely related
to eel ANP. Antarctic fish ANP has not yet been sequenced, but if it is
presumed similar to the eel ANP there is a strong homology with the amammalian ANP.
ANP in Heart Extracts and Plasma of Antarctic Teleosts
ANP radioimmunoassay of heart homogenates and plasma were performed
in Chionodraco hamatus and Trematomus bernacchii, using standard
protocols (RIA, Peninsula Lab. Belmomt, CA) and antibodies to a-rANP
(99-126) [22]. The levels of ANP-like peptides in plasma and heart of
Chionodraco were twice the corresponding values in Trematomus (Fig. 2).