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Pharmacologic actions of synthetic atrial natriuretic peptide in turkeys
j Mol Cell Cardiol 19 (Supplement IV) (1987)
139 PHARMACOLOGIC ACTIONS OF SYNTHETIC ATRIAL NATRIURETIC PEPTIDE IN TURKEYS. J.C. Lee, V.A. Roweand C.J. McGrath. Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061. In contrast to mammals, there are very few a t r i a l natriuretic peptide (ANP) granules found in avian hearts. The purpose of this investigation was to assess the possible pharmacologic effect of synthetic ANP in turkeys. Intravenous injection of rat ANP (3-28) (rANP) in 5 conscious turkeys over the range 0.I ~g/kg to lO~g/kg produced a dose-related depressor response. Results are as follows (mean • SEM): Dose (~g/kg) max Decrease MABP (mmHg) This response was not affected by the pretreatment of birds with either 0.1 17.5 • 2.8 alpha or beta adrenergic blockade. 0.5 33.8 • 1.1 Intravenous infusion of rANP 1.0 55.0 • 1.8 (0.5 ~g/kg/min) for 5 min resulted 5.0 76.3 • 2.1 persistent hypotension. The urine (U) 10.0 87.5 • 3.8 output, U~=, UCI and Uu were increased about 60%, 20%, 10% and 10% from the control, respectively. These ~esults suggest that ANP receptors are present in the avian species. However, the physiologic actions of endogenous ANP in the avian remain to be c l a r i f i e d .
1 4 0 L O C A L I Z A T I O N AND REGULATION OF AN INTRARENAL RENIN-ANGIOTENSIN SYSTEM (RAS). Julie R. Ingelfinger, Kristin E. Elllson, Richard E. Pratt, Gary H. Gibbons, Victor J. Dzau. Brigham and Women's Hospital and The Children's Hospital, Boston, MA. We have performed studies on localization and regulation of an endogenous "intrarenal RAS which is independent from the circulating system. Using a rat liver angiotensinogen eDNA (pRang3) and renin eDNA (pDD-ID2) we demonstrated that angiotensinogen and r e n i n m R N A s are expressed in the WKY rat kidney. In situ hybridization studies performed using J S cRNA probes from the same eDNAs revealed angiotensinogen mRNA to be present primarily in renal tubules and arterioles, while renln mRNA was present in the juxtaglomerular apparatus. Renal angiotensinogenmRNA was stimulated 2*3-fold by low (0.02%) cf. high (3%) NaCI diet (p<.05). R e n i n m R N A was present almost exclusively in kidney cortex and increased 7-fold on low cf. high NaCl diet (p<.05). Hepatic angiotensinogen mRNA, on the other hand, was not NaCI regulated, demonstrating tissue specific regulation. This phenomenon is further supported by the observation that renal angiotensinogen mRNA increased dramatically with puberty but not liver angiotensinogenmRNA. This effect is mediated by androgen. Taken together these studies show the presence on a complete endogenous, regulatable RAS which appears to function independently from the circulating RAS and the RAS in other tissues.
141
EVIDENCE FOR SPECIES SPECIFIC RENIN PROCESSING AND SECRETION IN TRANSFECTED CELLS. Martin Paul, Norifumi Nakamura, Richard E. Pratt, David W. Burr, Julie Flynn, Victor J.Dzau, Brigham and Women's Hospital, Boston, MA. The secretory pattern of kidney renin, the initiating enzyme of angiotensin formation, is different in various species. In the mouse, intracellular processing is very rapid and renin is secreted mostly in the mature active form; in the human, the processing is considerably slower and both mature renin and prorenin are secreted. To determine if these differences are due to different gene structures, we transformed two fibroblast cell lines (CHO, L929) and a mouse endocrine cell line (AtT 20) with identical expression vectors containing a RSV-LTR and either the mouse (RSV-ID2) or human renin gene (pm HR A). Transfected L929 and CHO cells secreted almost exclusively mouse or human prorenin as was verified by trypsin activation and pulse labelling studies. AtT 20 cells exhibited a different pattern of renin secretion. Cells transfeeted with the mouse gene secreted equal levels of prorenin and renin, whereas cells transfeeted with the human gene secreted five times more prorenin than active renin. These results show that renin gene stuctures influence renin biosynthesis and secretion in a species dependent fashion when introduced into a secretory cell line. We conclude that regulation of renin processing is both cell- and species-specific.
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139 PHARMACOLOGIC ACTIONS OF SYNTHETIC ATRIAL NATRIURETIC PEPTIDE IN TURKEYS. J.C. Lee, V.A. Roweand C.J. McGrath. Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061. In contrast to mammals, there are very few a t r i a l natriuretic peptide (ANP) granules found in avian hearts. The purpose of this investigation was to assess the possible pharmacologic effect of synthetic ANP in turkeys. Intravenous injection of rat ANP (3-28) (rANP) in 5 conscious turkeys over the range 0.I ~g/kg to lO~g/kg produced a dose-related depressor response. Results are as follows (mean • SEM): Dose (~g/kg) max Decrease MABP (mmHg) This response was not affected by the pretreatment of birds with either 0.1 17.5 • 2.8 alpha or beta adrenergic blockade. 0.5 33.8 • 1.1 Intravenous infusion of rANP 1.0 55.0 • 1.8 (0.5 ~g/kg/min) for 5 min resulted 5.0 76.3 • 2.1 persistent hypotension. The urine (U) 10.0 87.5 • 3.8 output, U~=, UCI and Uu were increased about 60%, 20%, 10% and 10% from the control, respectively. These ~esults suggest that ANP receptors are present in the avian species. However, the physiologic actions of endogenous ANP in the avian remain to be c l a r i f i e d .
1 4 0 L O C A L I Z A T I O N AND REGULATION OF AN INTRARENAL RENIN-ANGIOTENSIN SYSTEM (RAS). Julie R. Ingelfinger, Kristin E. Elllson, Richard E. Pratt, Gary H. Gibbons, Victor J. Dzau. Brigham and Women's Hospital and The Children's Hospital, Boston, MA. We have performed studies on localization and regulation of an endogenous "intrarenal RAS which is independent from the circulating system. Using a rat liver angiotensinogen eDNA (pRang3) and renin eDNA (pDD-ID2) we demonstrated that angiotensinogen and r e n i n m R N A s are expressed in the WKY rat kidney. In situ hybridization studies performed using J S cRNA probes from the same eDNAs revealed angiotensinogen mRNA to be present primarily in renal tubules and arterioles, while renln mRNA was present in the juxtaglomerular apparatus. Renal angiotensinogenmRNA was stimulated 2*3-fold by low (0.02%) cf. high (3%) NaCI diet (p<.05). R e n i n m R N A was present almost exclusively in kidney cortex and increased 7-fold on low cf. high NaCl diet (p<.05). Hepatic angiotensinogen mRNA, on the other hand, was not NaCI regulated, demonstrating tissue specific regulation. This phenomenon is further supported by the observation that renal angiotensinogen mRNA increased dramatically with puberty but not liver angiotensinogenmRNA. This effect is mediated by androgen. Taken together these studies show the presence on a complete endogenous, regulatable RAS which appears to function independently from the circulating RAS and the RAS in other tissues.
141
EVIDENCE FOR SPECIES SPECIFIC RENIN PROCESSING AND SECRETION IN TRANSFECTED CELLS. Martin Paul, Norifumi Nakamura, Richard E. Pratt, David W. Burr, Julie Flynn, Victor J.Dzau, Brigham and Women's Hospital, Boston, MA. The secretory pattern of kidney renin, the initiating enzyme of angiotensin formation, is different in various species. In the mouse, intracellular processing is very rapid and renin is secreted mostly in the mature active form; in the human, the processing is considerably slower and both mature renin and prorenin are secreted. To determine if these differences are due to different gene structures, we transformed two fibroblast cell lines (CHO, L929) and a mouse endocrine cell line (AtT 20) with identical expression vectors containing a RSV-LTR and either the mouse (RSV-ID2) or human renin gene (pm HR A). Transfected L929 and CHO cells secreted almost exclusively mouse or human prorenin as was verified by trypsin activation and pulse labelling studies. AtT 20 cells exhibited a different pattern of renin secretion. Cells transfeeted with the mouse gene secreted equal levels of prorenin and renin, whereas cells transfeeted with the human gene secreted five times more prorenin than active renin. These results show that renin gene stuctures influence renin biosynthesis and secretion in a species dependent fashion when introduced into a secretory cell line. We conclude that regulation of renin processing is both cell- and species-specific.
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