Characteristics of dendroaspis natriuretic peptide and its receptor in streptozotocin-induced diabetic rats.
Dendroaspis natriuretic peptide (DNP) shares a functionally important sequence homology with other natriuretic peptides. However, the characteristics of DNP and its receptor in the context of diabetes remafin to be fully elucidated. In the present study, alterations in the plasma levels and tissue contents of DNP and the properties of its receptor in diabetic rats, induced by streptozotocin (STZ) injection, were investigated. The plasma levels of DNP were 90.01 ± 4.12 and 196.68 ± 5.60 pg/ml in the control and STZ-induced diabetic rats, respectively. The tissue contents of DNP in the cardiac atrium, ventricle, renal cortex and inner medulla of the STZ-induced diabetic rats were also significantly increased compared with the control rats. Specific (125)I-DNP-binding sites were located predominantly in the glomeruli and inner medulla of the rat kidney. In the glomeruli of the kidney, the apparent dissociation constants (Kd) of (125)I-DNP in the control and STZ-induced diabetic rats were 0.41 ± 0.03 and 0.56 ± 0.06 nM, respectively. The maximum binding capacities (Bmax) of (125)I-DNP in control and STZ-induced diabetic rats were 2.98 ± 0.21 and 6.22 ± 1.06 fmol/mg protein, respectively. However, no differences were observed in the apparent Kd and Bmax of (125)I-DNP in the inner medulla of the kidney between the control and STZ-induced diabetic rats. In the glomerular and inner medullary kidney membranes, DNP stimulated the production of cyclic guanosine monophosphate (cGMP) in a dose-dependent manner. The magnitude of cGMP production in glomerular membranes was greater in the STZ-induced diabetic rats, whereas the magnitude of cGMP production in the inner medullary membranes was lower in the STZ-induced diabetic rats compared with the control rats. These results indicated that STZ-induced diabetes modulate DNP and its receptor, and also suggested that modulation of the DNP system is involved in the renal function of diabetic animals via the intracellular domain of the kidney NP receptor.
Department of Internal Medicine, Medical School, Wonkwang University, Iksan, Jeonbuk 570‑749, Republic of Korea.
Byoung Hyun
BH
Park
Department of Physiology, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561‑180, Republic of Korea.
Sun Young
SY
Kim
Department of Physiology, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561‑180, Republic of Korea.
Soo Mi
SM
Kim
Department of Internal Medicine, Medical School, Wonkwang University, Iksan, Jeonbuk 570‑749, Republic of Korea.
Hye Jung
HJ
Noh
Department of Internal Medicine, Medical School, Wonkwang University, Iksan, Jeonbuk 570‑749, Republic of Korea.
Chong Gu
CG
Cho
Department of Physiology, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561‑180, Republic of Korea.
Sung Zoo
SZ
Kim
D000818:Animals; D001665:Binding Sites; D006152:Cyclic GMP / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D004546:Elapid Venoms / Q000097:blood* / Q000378:metabolism; D006325:Heart Atria / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007457:Iodine Radioisotopes / Q000737:chemistry; D007678:Kidney Glomerulus / Q000378:metabolism; D007679:Kidney Medulla / Q000378:metabolism; D008297:Male; D010455:Peptides / Q000097:blood* / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin / Q000633:toxicity
C075597:Dendroaspis natriuretic peptide; D004546:Elapid Venoms; D036341:Intercellular Signaling Peptides and Proteins; D007457:Iodine Radioisotopes; D010455:Peptides; D013311:Streptozocin; D006152:Cyclic GMP