DIRECT EFFECTS OF ANGIOTENSIN-I, ANGIOTENSIN-II, AN ACE-INHIBITOR ANDA SERINE PROTEINASE-INHIBITOR ON CULTURED HEART-CELLS FROM SPONTANEOUSLY HYPERTENSIVE RATS
H. Kuzuo et al., DIRECT EFFECTS OF ANGIOTENSIN-I, ANGIOTENSIN-II, AN ACE-INHIBITOR ANDA SERINE PROTEINASE-INHIBITOR ON CULTURED HEART-CELLS FROM SPONTANEOUSLY HYPERTENSIVE RATS, Clinical and experimental pharmacology and physiology, 22(2), 1995, pp. 82-86
1. The purpose of the present study was to investigate how angiotensin
I(AI), angiotensin II (An), an angiotensin converting enzyme inhibito
r (ACE inhibitor; ACE-I) and a serine proteinase inhibitor contribute
to the protein metabolism of cultured newborn spontaneously hypertensi
ve rats (SHR) heart cells. We examined the uptake of [H-3]-uridine and
[H-3]-proline into cultured cardiac myocytes and fibroblasts, respect
ively. 2. Both AI and AII increased the uptake of [H-3]-uridine into m
yocytes in a concentration-dependent manner. However, the effect of AI
was denied in the presence of the ACE-I with the concentration of 10(
-6) g/mL. Both AI and AII increased the uptake of [H-3]-proline into c
ardiac fibroblasts in a concentration-dependent manner. However, this
effect was only partially abolished in the presence of 10(-6) g/mL of
the ACE-I, which was the maximal concentration that did not exert any
effect on the [H-3]-proline uptake. In the presence of AII receptor an
tagonist, [Sar(1), Leu(8)]-AII, the uptake of [H-3]-proline into cardi
ac fibroblasts was completely inhibited. Moreover, the stimulatory eff
ects of AI on the uptake of [3H]proline into cardiac fibroblasts were
completely inhibited in the presence of a serine proteinase inhibitor
in addition to the ACE-I.3. These results suggest that an ACE-I has di
fferent effects on protein metabolism in the heart and also suggest th
e presence of serine proteinase in cultured cardiac fibroblasts from S
HR.