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Renin-angiotensin system, kallikrein-kinin system and atrial natriuretic peptide in the rat's developing heart
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Renin-like activity, angiotensin I converting enzyme-like activity and osmoregulatory peptides in the dogfish rectal gland
No full textRenin-like activity, angiotensin I converting enzyme-like activity and osmoregulatory peptides in the dogfish rectal gland
No full textRenin-like activity (RLA) and angiotensin I-converting enzyme-like activity (ACELA), two key enzymes of the renin-angiotensin cascade (RAS), were sought in the dogfish rectal gland. RLA was 1.1 +/- 0.2 ng Ang I/mg protein/hr after incubation with porcine angiotensinogen and 0.8 +/- 0.1 ng Ang I/mg protein/hr after incubation with homologous plasma. ACELA was 7.22 +/- 1.08 and 8.87 +/- 1.9 nmol hippurate generated/min/mg protein respectively, at 0 and 37 degrees. The presence of these enzymes may indicate the presence of an endogenous RAS-like system in the rectal gland. Angiotensin II (Ang II) and atrial natriuretic peptide (ANP) binding sites were demonstrated autoradiographically in the subcapsular region of the gland, suggesting a possible interaction of the two hormones in the blind outer ends of the rectal gland tubules. Immunoreactivities toward Ang II, ANP, bombesin, vasoactive intestinal polypeptide (VIP), glucagon, and somatostatin were differentially localized in the rectal gland within three concentric zones with potentially different functional activities. In the capsule, there was a strong positive ir-glucagon reaction and a slightly weaker reaction for ir-somatostatin and VIP. In the blind outer ends of the tubules (in the subcapsular zone), strong immunoreactivity was present toward all the tested peptides except glucagon and somatostatin. In the inner zone and in the central canal, only a weak immunoreactivity toward Ang II and glucagon was observed
A local Renin Angiotensin System in the heart of an African lungfish, Protopterus annectens.
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Immunoreactive Atrial Natriuretic-like Peptide in Antarctic Teleosts
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1. The presence of an atrial natriuretic-like peptide (ANP) has been investigated in the Antarctic fish Chionodraco hamatus (Channichthydae) and Pagothenia bernacchii (Notothenidae).
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2. By radioimmunoassay an ANP-like peptide has been detected in plasma and heart homogenates of both white blooded (Chionodraco) and red blooded (Pagothenia) species.
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3. By immunohistochemistry atrial nutriuretic factor (ANF) immunoreactive cardiocytes have been demonstrated in the atria of Chionodraco and Pagothenia using Ab to rat 99–126 ANF. Ventricular immunoreactivity is absent in both species.
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4. ANP binding sites have been visualized by autoradiography in the kidney, gills and heart of both Pagothenia and Chionodraco.
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5. Our data indicate that ANP concentration is greater in the white blooded than in the red blooded fish
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