scholarly journals Effect of acute stimulation of renin secretion on renal renin content in vivo

1990 ◽  
Vol 38 (3) ◽  
pp. 440-446 ◽  
Author(s):  
John A. Opsahl ◽  
Paul A. Abraham ◽  
Stephen A. Katz
Keyword(s):  
Renin Secretion ◽  
Renin Content ◽  
Stimulation Of

Preserved macula densa-dependent renin secretion in A1 adenosine receptor knockout mice

2003 ◽  
Vol 284 (4) ◽  
pp. F770-F777 ◽  
Author(s):  
Frank Schweda ◽  
Charlotte Wagner ◽  
Bernhard K. Krämer ◽  
Jürgen Schnermann ◽  
Armin Kurtz
Keyword(s):  
Mrna Expression ◽  
Glomerular Filtration ◽  
Knockout Mice ◽  
Macula Densa ◽  
Salt Transport ◽  
Renin Secretion ◽  
Renin Mrna ◽  
Renin Content

Recent studies demonstrated that the influence of the macula densa on glomerular filtration is abolished in adenosine A1 receptor (A1AR) knockout mice. Inasmuch as the macula densa not only regulates glomerular filtration but also controls the activity of the renin system, the present study aimed to determine the role of the A1AR in macula densa control of renin synthesis and secretion. Although a high-salt diet over 1 wk suppressed renin mRNA expression and renal renin content to similar degrees in A1AR+/+, A1AR+/−, and A1AR−/−mice, stimulation of Ren-1 mRNA expression and renal renin content by salt restriction was markedly enhanced in A1AR−/− compared with wild-type mice. Pharmacological blockade of macula densa salt transport with loop diuretics stimulated renin expression in vivo (treatment with furosemide at 1.2 mg/day for 6 days) and renin secretion in isolated perfused mouse kidneys (treatment with 100 μM bumetanide) in all three genotypes to the same extent. Taken together, our data are consistent with the concept of a tonic inhibitory role of the A1AR in the renin system, whereas they indicate that the A1AR is not indispensable in macula densa control of the renin system.

Role of renin isoelectric heterogeneity in renal storage and secretion of renin.

1993 ◽  
Vol 4 (4) ◽  
pp. 1054-1063
Author(s):  
J A Opsahl ◽  
P A Abraham ◽  
J G Shake ◽  
S A Katz
Keyword(s):  
Renal Perfusion ◽  
Renin Secretion ◽  
Rabbit Kidney ◽  
Angiotensin Converting Enzyme Inhibition ◽  
Pool Model ◽  
Cellular Processing ◽  
Converting Enzyme Inhibition ◽  
Stimulation Of

Renin is a glycoprotein that is heterogeneous with respect to carbohydrate content and net charge. In an attempt to clarify the role of renin isoelectric heterogeneity in renal renin storage and secretion, the isoelectric profile of renal renin, secreted renin, and circulating renin were directly assessed and compared under basal and stimulated conditions by the use of an in vivo blood perfused rabbit kidney preparation. Under basal conditions, the kidney preferentially stored and secreted the relatively basic isoelectric forms of renin. Acute stimulation of renin secretion (reduced renal perfusion pressure and angiotensin-converting enzyme inhibition) significantly increased the secretion of the relatively basic isoelectric forms but had very little effect on the secretion of the relatively acidic renin forms. Circulating renin was composed primarily of relatively basic forms, which increased disproportionately after stimulation of renin secretion. These findings suggest that the isoelectric heterogeneity of renin is important in the cellular processing of renin and can be explained by a two-pool model in which the relatively acidic isoelectric forms of renin are constitutively secreted (and not stored) and the relatively basic isoelectric forms represent a regulated pathway in which they are stored and rapidly released in response to acute secretory stimuli. Preferential hepatic extraction of the more basic isoelectric forms has previously been described. Data from this study suggest that the disproportionate increase in circulating basic forms of renin observed after acute stimulation reflects the net effect of preferential renal the more basic renin isoelectric forms. The disproportionate increase in relatively basic circulating renin forms after acute secretory stimulation results in an overall circulating renin activity with a shorter half-life.

Renin secretion as a function of renal renin content in dogs

1978 ◽  
Vol 234 (6) ◽  
pp. F506-F509 ◽  
Author(s):  
C. S. Park ◽  
R. L. Malvin ◽  
R. D. Murray ◽  
K. W. Cho
Keyword(s):  
Total Content ◽  
Renal Perfusion ◽  
Secretion Rate ◽  
Renin Secretion ◽  
Fractional Rate ◽  
Rate Dependent ◽  
Secretion Rates ◽  
Renin Content

The in vivo and in vitro rates of renin secretion were measured in kidneys from five groups of dogs in which renal perfusion pressure, salt diet, and neural input were varied to cause large changes in renin secretion rates and renal renin content. It was found that both the in vivo and in vitro secretory rates were proportional to the renal renin content. However, in vitro secretion rates were dependent on content up to 100 ng angiotensin I/mg tissue per h. At higher renin contents no increment in in vitro secretion rate was seen. In vivo secretion rate did not appear to reach a maximum until renal renin content was above 250 ng AI/mg tissue per h. The data are interpreted to support the hypothesis that there exist at least two pools of renin. One releases renin at a fractional rate of about 1.5% of the total content per hour. The other releases renin at a rate dependent on the magnitude of the stimuli acting on the kidneys. It is also suggested that the rate of renin synthesis may be a determinant of the basla rate of renin secretion.

Circulating epinephrine stimulates renin secretion in anesthetized dogs by activation of extrarenal adrenoceptors

1984 ◽  
Vol 246 (5) ◽  
pp. F676-F684
Author(s):  
M. D. Johnson
Keyword(s):  
Renal Artery ◽  
Intravenous Infusion ◽  
Secretion Rate ◽  
Renin Secretion ◽  
Epinephrine Infusion ◽  
Clearance Studies ◽  
Anesthetized Dogs ◽  
Secretion Rates ◽  
Stimulation Of

The present experiments were designed to determine the location of the adrenoceptors responsible for initiating epinephrine-induced stimulation of renin secretion in vivo. Three hypotheses were tested: 1) the receptors are located intrarenally, 2) the receptors are located extrarenally , and 3) an interaction exists between intrarenal receptors and some event initiated by extrarenal receptors. All experiments were conducted in anesthetized dogs surgically prepared for renal clearance studies. Intravenous infusion of epinephrine at 250 ng X kg-1 X min-1 increased one-kidney renin secretion rate more than fivefold. In contrast, direct intrarenal infusion of epinephrine at 25 ng X kg-1 X min-1 only doubled renin secretion rate from the infused kidney. In six animals in which renin secretion rates were measured bilaterally during intrarenal epinephrine infusion, no differences in renin secretion rates were detected between the two kidneys. To examine the hypothesis that an interaction exists between intrarenal and extrarenal adrenoceptors, epinephrine was infused intravenously at 25 ng X kg-1 X min-1 and simultaneously into one renal artery at 10 ng X kg-1 X min-1. Renin secretion rates rose significantly (P less than 0.01) but equally from both kidneys. At lower epinephrine infusion rates (10 ng X kg-1 X min-1 intravenously plus 3 ng X kg-1 X min-1 intrarenally), renin secretion rates increased submaximally but still equally from both kidneys. It is concluded that epinephrine-induced stimulation of renin secretion in vivo is initiated by adrenoceptors located only extrarenally .

Stimulation of ovarian progesterone secretion by oxytocin in vivo

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S199-S200
Author(s):  
E. DIETRICH ◽  
K. RENTELMANN ◽  
W. WUTTKE
Keyword(s):  
Progesterone Secretion ◽  
Stimulation Of

scholarly journals GPR40 Is Necessary but Not Sufficient for Fatty Acid Stimulation of Insulin Secretion In Vivo

Diabetes ◽  
2007 ◽  
Vol 56 (4) ◽  
pp. 1087-1094 ◽  
Author(s):  
M. G. Latour ◽  
T. Alquier ◽  
E. Oseid ◽  
C. Tremblay ◽  
T. L. Jetton ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Fatty Acid ◽  
Insulin Secretion In Vivo ◽  
Stimulation Of

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Contamination of erythropoietin by endotoxin: in vivo and in vitro effects on murine erythropoiesis

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 146-158 ◽  
Author(s):  
KS Zuckerman ◽  
PJ Quesenberry ◽  
J Levin ◽  
R Sullivan
Keyword(s):  
Significant Inhibition ◽  
Erythropoietic Activity ◽  
Limulus Amebocyte Lysate ◽  
Endogenous Erythropoietin ◽  
Significant Change ◽  
In Vitro Effects ◽  
Stimulation Of

Abstract Endotoxin was detected in all erythropoietin preparations tested and was removed from four lots, without loss of erythropoietic activity, by adsorption with limulus amebocyte lysate. Comparison of adsorbed (endotoxin-depleted) and nonadsorbed (endotoxin-containing) erythropoietin preparations demonstrated significant inhibition of CFU- e and BFU-e in vitro by nonadsorbed erythropoietin at concentrations higher than 0.25 U/ml and 2.0 U/ml, respectively. CFU-e and BFU-e were inhibited significantly by readdition in vitro of 10(-5)-10(-3) mug of endotoxin per unit of limulus-adsorbed erythropoietin. Administration of saline or 6 U of nonadsorbed or adsorbed erythropoietin twice a day for 4 days of CF1 mice resulted in reticulocyte counts of 2.1%, 9.9%, and 15.9%, respectively. Nonadsorbed erythropoietin resulted in a 29% decrease in erythropoiesis, a 42% decrease in CFU-e, and a 16% increase in granulopoiesis in the marrow, whereas adsorbed erythropoietin caused a 28% increase in erythropoiesis, no significant change in CFU-e and a 19% decrease in granulopoiesis in the marrow. Both preparations resulted in marked increases in splenic erythropoiesis and granulopoiesis. The effects of adsorbed erythropoietin are similar to those produced following stimulation of hematopoiesis by endogenous erythropoietin. Hemopoietic changes induced by nonadsorbed erythropoietin in vivo and in vitro are affected substantially by contamination of the erythropoietin preparations with endotoxin.

Sign in / Sign up

Export Citation Format

Share Document