Download Plasma Levels of Adrenomedullin in Patients with

I35
Clinical Science (I998) 94, 135- I39 (Printed in Great Britain)
Plasma levels of adrenomedullin in patients with acute
myocardial infarction
Yuji YOSHITOMI, Toshio NISHIKIMP, Shunichi KOJIMA,Morio KURAMOCHI, Shuichi TAKISHITA*,
Hiroaki MATSUOKA*, Atsuro MIYATAt, Hisayuki MATSUOt and Kenji KANGAWAt
Department of Clinical Research, Tohsei National Hospital, Shizuoka. Japan, and *Division of Hypertension
and Nephrology, Notional Cardiovascular Center, 5-7-I Fujishirodai. Suita, Osaka 565. Japan, and
tResearch Institute, National Cardiovascular Center, 5-7-I Fujishirodai. Suita, Osaka 565, Japan
(Received 20 May/22 August 1997; accepted 10 September 1997)
1. Adrenomedullin, a newly identified vasorelaxant
peptide, participates in the regulation of the cardiovascular system. To investigate the pathophysiological significance of adrenomedullin in patients
with acute myocardial infarction, we measured
plasma levels of adrenomedullin.
2. Cardiac catheterization was performed on admission, after 1day, and after 4 weeks in 36 patients
with acute myocardial infarction. We measured
plasma levels of adrenomedullin, atrial natriuretic
peptide and brain natriuretic peptide in the right
atrium, pulmonary artery and aorta.
3. Plasma levels of adrenomedullin in the right
atrium (mean fSEM) were significantly increased
on admission (4.2f2.6 h) in patients with acute
myocardial infarction (10.6 f1.0 pmol/l) compared
with controls (5.2 0.3 pmol/l, P <0.01). In addition, plasma levels of adrenomedullin were further
elevated in patients with congestive heart failure
(123 +_ 1.4 pmol/l) compared with patients without
congestive heart failure (7.8 k0.6 pmol/l, P <0.01).
In patients with congestive heart failure, plasma
adrenomedullin on admission significantly correlated with atrial natriuretic peptide and brain
natriuretic peptide.
4. These results suggest that plasma adrenomedullin increases in the early phase of acute myocardial
infarction and that volume expansion may be one of
the additional stimuli for the release of adrenomedullin in patients with acute myocardial infarction
complicated by congestive heart failure.
INTRODUCTION
Adrenomedullin (ADM), recently identified from
extract of phaeochromocytoma tissue, has structural
homology to calcitonin gene-related peptide and
amylin [l]. Intravenous administration of ADM to
rats elicits a strong, long-lasting hypotensive effect
[2]. Considerable mRNA expression has been recog-
nized in large organs such as the heart, kidney and
lung [3]. Moreover, immunoreactive ADM has been
detected in human plasma [3]. Recent studies suggest that vascular smooth muscle cells possess
specific ADM receptors that are functionally
coupled to adenylate cyclase [4, 51. These findings
suggest the possibility that ADM is a peptide that
participates in the regulation of the cardiovascular
system. In fact, the plasma levels of ADM are
reported to be increased in patients with essential
hypertension, chronic renal failure and heart failure
[6-81. However, little is known about the pathophysiological significance of ADM in patients with
acute myocardial infarction (AMI).
Our objective was to determine the behaviour of
ADM in AMI. To that end, we measured plasma
levels of ADM in the right atrium, pulmonary artery
and aorta by specific radioimmunoassay in patients
with AMI. We examined ADM in relation to
haemodynamic and other parameters and humoral
factors in the acute and late phase of AMI.
METHODS
We studied 36 Japanese patients with AM1 (28
men, 8 women) aged 39 to 84 years (mean age & SD,
59 f13 years). The diagnosis of AM1 was based on
two of the three criteria: (i) typical ischaemic chest
pain lasting longer than 30 min, (ii) electrocardiographic ST-segment elevation of 0.1 mV in two contiguous leads, (iii) elevation of serum total creatine
kinase and its MB isoenzyme to at least twice the
upper limit of normal. We excluded from study
patients with a history of congestive heart failure,
chronic atrial tachyarrythmias, previous myocardial
infarction, chronic obstructive lung disease or
chronic renal failure. The average time from onset
of symptoms to admission was 4.2 f2.6 h (mean
+SD; 1.5-3 h, IZ = 17; 3-6 h, IZ = 7; 6-9 h, IZ = 12).
Patients with AM1 were classified into two sub-
Key words: acute myocardial infarction, adrenomedullin, atrial natriuretic peptide, brain natriuretic peptide, congestive heart failure.
Abbrcvirtionr: ADM, adrenomedullin:MI. acute myocardial infarction: ANP. atrial natriuretic peptide; BNP, brain natriuretic peptide.
Comspondenee Dr Toshio Nishikimi.
I36
Y.Yoshitomi et al.
groups: those with no signs and symptoms of cardiac
failure (Killip class I) (Group I) and those with
developing signs of dysfunction or cardiac decompensation (Killip class 11, 111 and IV) (Group 11) [9].
Before admission, 12 of the patients with AM1 had
been taking calcium antagonists. Three of the
patients with AM1 had been on angiotensin-converting enzyme inhibitors alone. All patients were
treated with calcium antagonists and nitrates after
admission. Diuretics were used in 13 patients with
congestive heart failure. None of them was treated
with B-blocker.
We also studied 12 age- and sex-matched control
subjects who were electively admitted to our hospital with a chief complaint of chest pain. The 10 men
and 2 women were aged 46 to 76years (mean
age & SD, 61 9 years). All subjects electively underwent cardiac catheterization and their findings were
normal. None of them had myocardial infarction,
hypertension, cardiac hypertrophy or other cardiovascular diseases. None of them was receiving
therapy at the time of the study.
Informed consent was obtained from each patient
and/or family in the early phase of AM1 and again
later from each patient. This study protocol was in
agreement with the guidelines of the committee on
ethics of Tohsei National Hospital and National
Cardiovascular Center.
Right-sided cardiac catheterization, coronary
arteriography and left ventriculography were performed in all patients as soon as patients were
admitted. Right atrial, pulmonary arterial and pulmonary capillary wedge pressures were measured by
a Swan-Ganz thermodilution catheter (Model
93A-431H-7.5Fr, Baxter Healthcare Co., CA,
U.S.A.). Cardiac output was calculated by the thermodilution method [lo]. Twenty-eight of the 36
patients underwent direct percutaneous transluminal
coronary angioplasty, while four patients underwent
percutaneous transluminal coronary recanalization
via the intracoronary infusion of prourokinase. The
remaining four patients were treated conservatively
because the infarct-related coronary arteries were
patent at the time of coronary arteriography. A
second cardiac catheterization was performed on
1 day after admission to see whether or not infarctrelated coronary artery was patent. Infarct-related
coronary arteries were patent in 33 of 36 patients.
Four weeks after admission, 33 patients underwent
another cardiac catheterization. At that time, the
infarct-related coronary artery was patent in 30
patients. Left ventricular ejection fraction was calculated using the area-length method.
Blood samples were obtained from the right
atrium, pulmonary main trunk and ascending aorta
before the pressure recording was made. After
blood sampling, arteriography and left ventriculography were routinely performed. Blood samples
were collected on admission, 1 day after admission
and 4 weeks after the treatment of AMI. The 7 ml
blood samples were added to chilled tubes contain-
ing disodium EDTA (1 mg/ml) and aprotinin (500
kallikrein-inhibiting units/ml) and were centrifuged
immediately at 4°C. The plasma samples were stored
at -80°C until they were extracted before radioimmunoassay. For radioimmunoassay, Sep-Pak C18
cartridges (Waters of Millipore, Milford, U.S.A.)
were prewashed sequentially with 5 ml each of
chloroform, methanol, 50% acetonitrile containing
0.1% trifluoroacetic acid, 0.1% trifluoroacetic acid
and saline solution. A 2ml sample of plasma was
acidified with 24 p1 of 1mol/l hydrochloric acid and
diluted with 2ml of saline solution, then loaded
onto a Sep-Pak C18 cartridge. After being washed
with 5 ml each of saline solution, and 0.1% trifluoroacetic acid, the absorbed materials were eluted with
4 ml of 50% acetonitrile containing 0.1% trifluoroacetic acid. The eluate was then lyophilized. The
lyophilized material was dissolved in radioimmunoassay buffer, and the clear solution was submitted to
radioimmunoassay. The radioimmunoassay for
ADM was described previously [6]. Delta ADM was
calculated as plasma levels of ADM in the pulmonary artery minus plasma levels of ADM in the
aorta. Plasma levels of atrial natriuretic peptide
(ANP) and brain natriuretic peptide (BNP) were
measured by Shiono RIA ANP and Shiono RIA
BNP assay kit (Shionogi Co., Osaka, Japan) as
reported previously [ 111.
Comparisons between two groups were evaluated
with the x2 test, the paired Student’s t-test, or the
unpaired Student’s t-test if appropriate. Comparisons among multiple groups were performed with
the one-way analysis of variance followed by
Scheffe’s test, the one-way analysis of variance for
repeated measures or the two-way analysis of variance for repeated measures, as appropriate. Correlation coefficients were calculated by linear
regression analysis. A level of P < 0.05 was accepted
as statistically significant.
RESULTS
Baseline characteristics of the two groups are
shown in Table 1. There were no differences in age,
sex, time between onset and admission, site of myocardial infarction and treatment in the acute phase.
Of the 36 patients, 3 patients died during the study
protocol. Two patients in group 11 died on the
second or third day because of cardiogenic shock,
and one patient in group I died in the third week
due to the complication of pneumonia.
Haemodynamic parameters and plasma levels of
ANP and BNP in the right atrium among the three
groups are shown in Table 2. Plasma levels of ANP
and BNP were significantly higher in group I1 than
in the control group. In addition, there was a significant difference in plasma levels of BNP between
group I and group 11. In group 11, mean pulmonary
capillary wedge pressure and mean pulmonary
arterial pressure significantly decreased on 1 day
Adrenomedullin in myocardial infarction
I37
Table I. Clinical chamtea'rtier of patients with acute m y d i
infvaion without (gmup I) or with (grwp 11) congestive heart
hilun?.Valws are expressed as meansf SD. ACE, angiotensintomerting
enzyme; NS, not signifm: PTCA, percutaneous tranduminal coronary
a
n
g
o
ip
m
l PTCR percutaneous tranduminal coronary recanalition.
charaaeristic
Age (vean)
Sex (MIF)
Time between onset and admission (h)
Group I
(n = 14)
Group II
(n = 22)
P
56f11
l2R
4.8 4.2
63+13
I616
4.5k3.1
NS
NS
NS
14
6
2
NS
NS
NS
+
Site of myocardial infarction
Anterior
lnfwior
Lateal
6
6
2
onpdmissloa
lstday
4w e b
Treatment in acute phase (n)
PTCR
Direct PTCA
COnrervatiw
0
12
2
4
16
2
NS
NS
NS
Maximal creatine kinase (i.u.il)
2262+ I I73
3966k2512
NS
Medicationbefore admission (n)
Calcium antagonist
ACE inhibitor
5
I
7
2
NS
NS
Medicationafter admission (n)
Calcium antagonist
ACE inhibitor
Diuretics
Nmte
14
I
I
14
22
3
13
22
N5
NS
0.01
NS
after admission (20 f2 to 11 f2 mmHg, 29 f 2 to
20 f1 mmHg, respectively, P <0.05).
Patients with AM1 were divided into three groups
according to the time from onset to admission.
Plasma levels of ADM in the right atrium increased
within 3 h after the onset of symptoms and
remained elevated at least 9 h after the onset of
AM1 (AMI; 1.5-3 h: 10.7f 1.7 pmol/l; 3-6 h:
10.9k0.9 pmol/l; 6-9 h: 11.8 f 1.5 pmol/l; control;
5.2f0.3 pmolfl, P<O.Ol). As seen in Fig. 1, plasma
in patients with AM1 without (Group I) and with (Group ll) congesthe control group. Statistical signifiie:
*P<O.OI cornpared with control p u p ; tP<O.OI compared with at
4 weeks; $P<O.OI comparedwith group 1.
tive heart failure, and in
levels of A D M were significantly higher on admission in the patients with AM1 (10.6 f1.0 pmolfl,
P<O.Ol) than in the control group. Furthermore,
plasma levels of A D M were higher in group I1 than
in group I on admission. Plasma levels of ADM
remained elevated the next day and decreased at
4 weeks in patients with AMI. There were no significant differences in the plasma levels of ADM
between admission and the day after admission in
the patients with or without successful reperfusion
(10.8f 1.2 to 11.Of 1.3 pmolfl with reperfusion,
8.4 f0.8 to 8.7 f 0.7 pmolfl without reperfusion; not
significant). Plasma levels of A D M in the aorta tended to be lower than those in the right atrium or
pulmonary artery in patients with AM1 and the control group, but the differences were not statistically
significant (Fig. 2). However, the delta ADM in the
AM1 groups during protocol was higher than that in
the control group.
Table 2. Natriuretic peptides and haemodynarnic findings on
admission. R% right atrial pressure; m P W , mean pulmonary capillary
wedge pressure; mPA. mean pulmonary arterial pressure; mRA, mea,n right
atrial pressure; mA0, mean aortic pressure; LVEDP, left ventricular enddiastolic pressure; LVEF, left ventricular ejection fraction; CI, cardiac index.
Values are expressed as means+SEM. Statistical significance: *P<0.05
compared with control, tP<0.05 comparedwith group I.
Group I
(n = 14)
ANP in the RA (pg/ml)
BNP in the RA (pglml)
mPCWP (mmHg)
mPA (mmHg)
mRA (mmHg)
mA0 (mmHg)
LVEDP (mmHg)
LVEF (%)
CI (Imin-' m - 3
COnhd
Fig. I. Changer in plasma k v d s of adrenotdullin in the right atrium
30+7
40+ I I+
12k2
18+2
7+ I
104+6
15+2
52*4*
3.3 k 0 . 2
Group II
(n = 22)
PA
A0
ddt.PAtoA0
(n = 12)
7k I
9+ I
IS+ I
Il+l*t
105+4
26 2*t
43 3*
2.9 0.2'
4+ I
98+3
Ilk2
66+2
3.8k0.2
+
*+
W
Control
50+ 12'
I77 & 6 l * t
20 2*t
29 & 2*t
*
O M
5&1
On admission
1st day
4 w&
Control
Fig. 2. Changer in p-l
levels of adrenomedullin in the right atrium
(RA), pulmonary artery (PA) and aorta (AO) in patienk with AM1
and the control group. Delta adrenomedullin= plasma levels of adrenomedullin in the pulmonary artery minus plasma levels of adrenomedullin in
the aorta Statistical significance: *P<0.05 compared with the control group.
I38
Y. Yoshtorni et al.
Plasma levels of ADM on admission were significantly correlated with plasma levels of ANP
(r = 0.442; P <0.05) and BNP (r = 0.470; P < 0.05) in
group 11. On the other hand, plasma levels of ADM
did not correlate with plasma levels of ANP
(r=0.379; not significant) or BNP ( r = 0.089; not
significant) in group I. There were no significant
correlations between plasma levels of ADM and
haemodynamic parameters on admission in either
group of patients with AMI. There were no significant correlations between plasma levels of ADM
and other humoral factors or haemodynamic parameters on the day after admission and at 4 weeks in
either group of patients with AMI.
DISCUSSION
In the present study, we demonstrated that
plasma levels of ADM were increased rapidly in the
very early phase of AMI. Furthermore, plasma
levels of ADM in patients with congestive heart
failure were significantly higher than those in
patients without that complication and correlated
positively with plasma levels of ANP and BNP.
In AMI, plasma adrenaline and noradrenaline
levels increase within 2 h after onset of symptoms
[ 121. Previous studies reported a correlation
between plasma levels of ADM and plasma levels of
noradrenaline in patients with essential hypertension, chronic renal failure and congestive heart
failure [7, 81. According to the report of the genomic structure of human ADM gene, the 5’4anking
region contains binding sites for activator protein-2
and CAMP-regulated enhance elements, suggesting
that expression of the ADM gene may be subject to
the activity of protein kinase C and cAMP levels
[ 131. Because noradrenaline activates protein kinase
C and phospholipase C through the al-receptor,
increased plasma noradrenaline levels may affect the
gene expression of ADM through the al-receptor.
Furthermore, plasma noradrenaline levels were significantly greater in AM1 with congestive heart
failure than in uncomplicated AM1 [14]. This finding
suggested that an activated sympathetic nervous
system may also be related to increased plasma
levels of ADM in AM1 complicated by congestive
heart failure.
Activation of the renin-angiotensin system occurs
early in patients with AM1 [15]. Angiotensin I1 was
a potent stimulant of ADM gene expression among
vasoactive peptides [16]. Thus, activation of the
renin-angiotensin system in AM1 may be involved
in increased plasma levels of ADM. On the other
hand, immediate local responses include the accumulation and activation of monocytes and macrophages. These cells then release the acute-phase
cytokines, including interleukin la, interleukin-6 and
tumour necrosis factor [171. Interleukin-6 and
tumour necrosis factor are increased within 3 h in
AM1 [18, 191. Sugo et al. [20] reported that cyto-
kines such as tumour necrosis factor and interleukin-la markedly stimulated ADM production in
cultured rat vascular smooth muscle cells. Thus,
several cytokines and vasoactive substances may be
involved in the increased plasma levels of ADM in
the acute phase of AMI.
In addition, ANP and BNP correlated with ADM
only in patients with AM1 complicated by congestive
heart failure. These natriuretic peptides are known
to be an indicator of volume expansion [21, 221.
Therefore, volume expansion may also have the
additive stimulatory effect on ADM production in
the early phase of AMI.
Kobayashi et al. [23] have reported positive correlations between ADM and haemodynamic parameters in the early stage of AM1 in a small number of
patients. Our data differ somewhat from their study.
The absence of these correlations in our study group
indicated that in these haemodynamically wellrecovered patients, other factors may influence
ADM production and thereby obscure the relationship with haemodynamic parameters.
Nishikimi et al. [24] previously reported that the
lung was the partial clearance site of circulating
ADM in humans. There are many ADM binding
sites in the lungs and hearts in rats, found by using a
receptor binding assay technique [25]. In addition,
ADM receptor mRNA was highly expressed in the
lungs [26]. In the present study, uptake of circulating
ADM in the lungs, expressed by the delta ADM,
was larger in patients with AM1 than in the control
subjects. ADM reduced the lobar arterial pressure
of the feline in a dose-dependent manner in vivo
[27]. Therefore, ADM may reduce the pulmonary
resistance in patients with AM1 as a compensatory
mechanism.
Regardless of the reperfusion, there was no significant difference between plasma levels of ADM on
admission and those on the following day in our
patients with AMI. A previous study found no
increase in the plasma levels of ADM in the
coronary sinus relative to the aorta in patients with
ischaemic heart disease [24]. Therefore, the
coronary circulation may not largely affect the circulating ADM levels in the early phase of AMI.
The source of circulating ADM remains unknown.
Sugo et al. [28] reported that vascular endothelial
cells and vascular smooth muscle cells prominently
synthesize and secrete ADM in vitro. Other studies
showed that specific receptors for ADM are present
in cultured vascular smooth muscle cells and ADM
increases intracellular cAMP levels [ 1, 51. Although
the exact source of circulating ADM in humans is
unknown, these results suggest that the vascular wall
may be one of the important production sites of circulating ADM and may participate in the control of
vascular tone. The exact source of circulating ADM
needs to be studied further.
In the present study, plasma levels of ADM on
admission in patients with congestive heart failure
were lower than those reported by Cheung et al.
Adrenomedullin in myocardialinfarction
[29] (17.5 pmol/l). Blood samples were obtained at a
single time-point in the acute phase. The peak value
of plasma levels of ADM occurred 27 h after the
onset of AM1 [23]. It is possible that the timing of
blood sampling is an important point that may have
affected the difference between our study and the
study of Cheung et al. [29]. In addition, our radioimmunoassay system is different from theirs. Our
specific anti-ADM antibody recognizes the whole
ADM[1-521 structure and does not cross-react with
smaller fragments of ADM. Indeed, their normal
value of ADM is 7.8pmol/l, 1.5 times higher than
our normal value of 5.2pmol/l. Thus, higher ADM
levels in heart failure in their study may be due to
differences in specificity of the anti-ADM antibody
used.
Many physiological actions of ADM have been
reported. ADM decreases blood pressure, by
decreasing total peripheral resistance, and increases
urine flow and urinary sodium excretion [2, 30, 311.
Moreover, ADM dilates pulmonary artery and
decreases pulmonary vascular resistance [27]. The
observed increase of ADM in AM1 may compensate
heart failure by decreasing peripheral and pulmonary resistance or increasing urinary sodium and
water excretion.
In conclusion, plasma levels of ADM were
increased in the early phase of AM1 with or without
congestive heart failure and normalized after
1 month. Plasma levels of ADM were especially high
in patients with congestive heart failure and correlated with plasma levels of ANP and BNP. Our
results suggest that ADM is increased in AM1 and
that volume expansion may have the additive effect
on ADM production.
I39
5. Kato J,Kitamura K, Kangawa K, Eto T. Receptors for adrendullin in human
vascular endothdial cells. Eur J Pharmacol 1995; 289 383-5.
6. Kitamura K. lchiki Y, Tanaka M, et al. Immunweactk a d d u l l i n in human
plasma FEBS Lea 1994; 341: 286-90.
7. lshimim T. Nishikimi T, Saito Y, et al. Plasma levels of adrenomedullin,a newly
identified hypotensivepeptide. in patients with hypertension and renal failure.
J Clin lnwst 1994; 9 4 2 156-6 I.
6. Nishikimi T, Saito Y, Kitamura K, et al. Increased plasma levels of adrenomedullin
in patients with heart failure. J Am Coll Cardiol 1995; 2 6 1424-3 I.
9. Killip T, Kimbalj l . Treatment of a myocardial infarction in a coronary care unit:
a two year experience with 250 patients. Am J M i d 1967; 2 0 457-64.
10. kvett JM, Replogle RL. Thennodilution cardiac output A critical analys~sand
review of the literature. J Surg Res 1979 2 7 392-404.
I I. Yasw H, Yoshimura M, Sumida H. et al. Localizationand mechanism of secretion
of 6-type ~ t t i ~ r e tpeptide
ic
in comparim with those of A-type ~triuretic
and patients with heart failure. Circulation 1994; 90:
peptide in normal sub-
195-203.
12. Karlsberg RP, Ctyer PE. Roberts R Serial plasma catecholamine response early in
the cwrse d clinical acute myocardial infaraim relatiomhip to idarct extent
andmortali.AmHeartJ 1981; 10224-9.
13. lshimitsu T, Kojima M, Kangawa K, et al. G e m i c structure of human
adrenomedullingene. Biochem Biophys Res Commun 1994; 203 63 1-9.
14. Lubbecke F. kchatrxh S, Mtrovic V, et al. Catecholaminesand thrombocyte
a2-adrenoreceptors in patients with acute myocardialinfarction. Eur Heart
J 1991; 1288-91.
IS. M i c h o r d 6, CeremuzynskiL. The renin-angiotensin-aldosterme system and
the clinical course of acute myocardial infarction. Eur Heart J 1983; 4 259-64.
16. Suga S, Minamino N, Shoji H, Kangawa K, Matsuo H. Effects of vasoactive
substances and CAMP related compounds on adrenomedullinproduction in
cultured vascular smooth muscle cells. FEBS Lett 1995; 369 3 I I - 14.
17. Kushner I, Ganapathi M, Schultz D. The acute phase response is mediated by
heterogeneous mechanisms. Ann M' Acad Sci 1989 557 19-30.
18. MiyaoY, Yasue H, Ogawa H, et al. Elevated plasma interleukindlevels in
patients with acute myocardial infarction. Am Heart J 1993; 126 1229-304.
19. Latini R Bianchi M. Correale E, et al. Cytokines in acute myocardial infarction:
20.
2 I.
22.
ACKNOWLEDGMENTS
23.
We thank Ms Yoko Saito for technical assistance
and Ms Hiromi Hosaka for secretarial assistance.
24.
selective increase in circulating tumor necrosis factor, its sduMe receptor, and
interleukin-I receptor antagonist. J Cardiovasc Phamacd 1994; U: 1-6.
Sugo S, Minamino N, Shoji H, et al. Interleukin-I,tumor necrosis factor and
lipopdysacdwide additively stimulate production of adrenomedullinin vascular
smooth muscle cells. Biochem B i h y s Res Commun 1995; 207: 25-32.
Stevens TL, BurnettJC, Kinoshita M, M a d Y, Redfdd MM. A functional role
for endogenous atrial natriuretic peptide in a canine model of early left
ventricular dysfunction.J Clin Invest 1995; 95: I I01-8.
Mukoyama M, Nakao K, Horoda K, et al. Brain natriuretic peptide as a novel
cardiac hormone in humans. J Clin lnwst I99 I; 8 7 1402- 12.
Kobayashi K, Kitamura K, Hirayama N. et al. Increased plasma adrenomedullinin
acute myocardial infarction. Am Heart J I996 I 3 I :676-80.
Nishikimi T, Kitamura K, Saito Y, et al. Clinical studies on the sites of production
and clearance of circulating adrenomedullinin human sub@. Hypertension
1994; 2 4 600-4.
25. Owji 4Smith DM, Coppock HA, et al. An abundant and speck binding site
for the novel vasodilator adrenomedullinin the rat. Endocrindogy (Baltimore)
REFERENCES
I. Kitamura K, Kangawa K, Kawamoto M. et al. Adrenomedullin: a novd
hypotensivepeptide isdated from human pheochromocytcma Biochem Biophys
Res Commun 1993; 192 553-60.
2. lshyamaY, Kitamura K, lchiki Y. et al. Hemodynamic effects of a novel
hypotenrive peptide, human adrenomedullin, in rats. Eur J Pharmacd 1993; 241:
271-3.
3. Kitamura K, Sakata J, Kangawa K, Kojima M, Matsuo H, Eto T. Cloning and
&ammimion of cDNA encoding a precursor for human adrenomedullin.
B h m B i m Res Commun 1993; 194: 720-5.
4. E@i S, Hirata Y, KMO H, et al. Specik receptm for adrenomedullinin
cultured rat vascular m t h muscle cdls. FEBS Lett 1994;340: 226-230.
1995; 136 2127-34.
26. Kapas S. Catt KJ. Clark AJL. Cloning and expression of cDNA encodinga rat
adrenomedullinreceptor. J Bid Chem 1995; 270 25344-7.
27. Lippton H, Chang JK, Hao Q.Summer W. Hymn AL. A d d u l l i n dilates
the pulmonaryvascular bed in vivo. J Appl F'hysid 1994; 7 6 2 154-6.
28. Sugo S, Minamino N, Kangawa K, et al. Endothdialcells xtdy synthesize and
secrete adrenomedullin. Biochem Biophys Res Commun 1994;201: 1160-6.
29. Cheung 6. Leung R Elevated plasma levels of human sdrwKwduUin in
cardiovascular, rerpiatq, hepabc and renal disorders. Clin Sci 1997; 9 2 59-62.
30. H i m Y, Hayakawa H, Suzuki Y, et al. Mechanisms of adrenomedullin-induced
d i l a t i o n in the rat kidney. H.ypertension 1995; 2 5 790-5.
3 I. Eban T, Miura K, Okumura M, et al. Effect of adrenomedullinon renal
hernodynamicsand functions in dogs. Eur J pharmscd 1994; 263: 69-73.