PGE2및 PGF2α가 삼투성 용혈 및 적혈구막Ca++ 결합에 미치는 영향

Abstract

[영문]

[한글]

PGE^^2와 PGF^^2α는 체내 여러 조직에서 유사한 작용을 나타내기도 한다. 예를 들면

이들 두 물질은 모두 황체 퇴화를 촉진하며(Poiser, 1972: Fuchs 등, 1974: Coudert 등,

1974) 자궁근수축을 항진시킨다 (Laudanski 등, 1977: Porter 등, 1979; Hollingsworth

등, 1980).

PGE^^2는 적혈구막의 취약성을 증가시키는데 (Rasmussen 등, 1975)사람의 적혈구에는 a

denylate cyclase 활성도가 아주 낮거나(Rodan 등, 1976) 없는것(Sutherland 등, 1962)으

로 알려져 있으므로 PGE^^2에 의한 적혈구 취약성의 변화는 c-AMP와는 무관할 것이다. 또

PGE^^2에 의해서는 적혈구막 단백질의 2차 구조가 변화하므로(Meyers 및 Swislocki, 197

4) PGE^^2 및 PGF^^2α에 의하여 세포막 성상이 변화될 가능성이 있다. 본 실험에서는 PG

E^^2 및 PGF^^2α 투여시 적혈구막의 삼투성 취약성의 변화와 적혈구막절편의 Ca++결합에

미치는 영향을 상호비교하여 적결구막에 대한 이들 물질의 작용 기전의 일부를 규명하고

자 본 실험을 시행하여 다음과 같은 결과를 얻었다.

1. PGF^^2α는 PGE^^2와 같이 적혈구막 삼투성 취약성을 증가시키는데 대조군에서는 Na

Cl 농도 1/18 M 용액에서 완전히 용혈되었으나 PGE^^2 및 PGF^^2α가 10**-11 M이상 포함

될 경우 NaCl농도 1/16∼1/17 M에서 100% 용혈이 일어났다.

2. 동일한 적혈구 부유액을 사용할 때 NaCl농도 1/15 M 용액에서 대조군은 44.2±4.3%

가 용혈되나 PGE^^2 및 PGF^^2α가 10**-11 M 농도로 포함되었을 때 용혈은 각기 73.6±8

.4% 및 68.7±6.4%로 급격히 증가하였으며 그 이상의 농도에서는 더 이상 증가를 보이지

않았다.

3. PGE^^2 및 PGF^^2α에 의해 증가된 용혈은 어느 Ca++농도에서도 대조군 보다 항상

일정한 정도로 증가되어 있다.

4. 적혈구악 절편에 결합하는 45**ca은 incubation용액내 cold Ca++이 증가함에 따라

지수함수적으로 감소하였다. 이것은 적혈구막 절편에서의 Ca++결합이 specific receptor

와의 결합임을 암시한다.

5. 적헐구막 절편에서의 Ca++결합은 대조군이나 PGE^^2 및 PGF^^2α 처치군 모두 incub

ation용액내 Ca++농도가 증가함에 따라 곡선적으로, 증가하여 Ca++농도 5mM에서 포화된다

. 그러나 같은 농도의 Ca++에서 비교할 때 적혈구막의 Ca++결합은 PGE^^2 및 PGF^^2α 존

재시 대조군에 비하여 증가되었다.

이상의 결과로 보아 PGE^^2 및 PGF^^2α가 적혈구악의 삼투성 취약성을 증가시키는 기

전은 Ca++과는 독립적으로 작용함을 알 수 있다.

Effects of PGE^^2 and PGF^^2α on the osmotic fragility and membrane Ca++ binding

in human erythrocytes

Dong Soo Yeoun

Department of Medical Science The Graduate School Yonsei University

(Directed by Prof. Doo Hee Kang, M.D., Ph.D.)

PGE^^2 and PGF^^2α are known to act similarly in a number of animal tissues.

They both facilitate regression of corpus luteum (Poyser, 1972; Fuch et al, 1974;

Coudert et al, 1974) and stimulate contraction of uterine muscle (Laudanski et al,

1977; Porter et al, 1979: Hollingsworth et al, 1980). It is, however, not known

whether these two prostaglandins exert similar actions in osmotic fragility of

erythrocytes (Rasmussen et al, 1975) and PGF^^2α alters conformation of membrane

proteins (Meyers and Swislocki, 1974). The former effect may not be mediated

through changes in c-AMP concentration in the cell, since the adenylate cyclase

activity in human erythrocyte is extremely low (Rodan et al, 1976: Sutherland et

al, 1962) and the later effect implies that physical state(or fluidity) of the

membrane is altered by PGF^^2α.

The present stuffy was undertaken to elucidate mechanisms of action of PGE^^2 and

PGF^^2α on the human erythrocyte membrane by examining their effects on osmotic

fragility and Ca++ binding to the membrane fragments. The results are summarized as

follows :

L. PGE^^2 and PGF^^2α increased osmotic fragility at concentrations above

10**-11 M, the effect being similar for both hormones. The concentration of NaCl

for 100% hemolysis was 1/16 - 1/17 M in the presence of 10**-11 M PGE^^2 or

PGF^^2α and 1/18 M in the absence of the hormone(control).

2. When erythrocytes were suspended in 1/15 M NaCl solution, 44.2±4.3% of cells

were hemolyzed. Addition of 10**-11 M PGE^^2 or PGF^^2α dud not increase

hemolysis. When the concentration of the hormones was increased to 10**-11 M,

however the degree of hemolysis Increased markedly to about 80%. No further

increase in hemolysis was observed at concentration of the hormone above 10**-11 M.

3. The additional hemolysis due to 10**-11 M PGE^^2 and PGF^^2α appeared to be

identical regardless of absence or presence of Ca++ (0.5-10mM) in the suspending

medium.

4. The amount of 45**Ca binding to the erythrocyte membrane fragment, declined

exponentially as the cold Ca++ concentration in the medium increased, indicating

that Ca++ ions bind to specific receptor(s) in the membrane.

5. In the absence of prostaglandin, the binding of Ca++ to the erythrocyte

membrane increased curvilinearly as the Ca++ concentration increased upto 5mM above

which it leveled off. A similar dependence of Ca++ binding on the Ca++

concentration was observed in the presence of 10**-11 M PGE^^2 or PGF^^2α,

however, the amount of Ca++ bound at a given Ca++ concentration was significantly

higher than in the absence of the hormones.

6. As in the hemolysis, PGE^^2 and PGF^^2α did not affect the Ca++ binding at a

concentration of 10**-12 M, but increased it by about 100% at concentration above

10**-11 M. these result indicate that both the osmotic fragility of erythrocyte and

the Ca++ binding to the erythrocyte membrane are similarly enhanced by PGE^^2 and

PGF^^2α, but theme two effects are not causally related.

It is, therefore, concluded that the prostaglandin-induced hemolysis is not

directly associated with alterations of the Ca++ content in the membrane.