Succinic Dehydrogerlase Activity

10.0 mxIcIn IMPACT ON SUCCINIC - ACTIVITY 10.1 TNTROWCTION

Organic and inorganic toxicante have deleterious effect

on the physiology of aquatic organisms. Many investigators have

atudied the effects of pesticides on cellular enzymes in both

vertebrate and invertebrate tissues (Johnston, 1950; Sacktar.1950;

Jackim & d., 1970; Mc Corkle and Yarbrough 1974). Other

workers have also studied the influence of pollutants on various

enzymes in fishes (Christensen. 197:; Christensen & d., 1972;

Mukharjee and Bhattacharya, 1974. 1975).

Low doses of many chemicals have toxic effects on the

metabolism by altering normal enzyme activity. The succinic

dehydrogenase sy~tem of rat heart was found to be inhibited by in

vitro effects of DIQ and related compounds t Johnston, 1950) Nath

et a. (19'78) reported a marked increase in succinic dehydrogenase, activity levels of liver and kidney of rats when treated with

endo~ulf an and metapa .

Studie~ on the toxic effects 3f heavy met.als on succinic

dehydrogenase activity are very scanty in amphihis, particularly

in the green frog Bans -. Variatio~~s in total free

aminoacids and amino transferase act.ivity as a function of

dcnervation atrophy and ammonia stress in selected tissue of frog

hesadactvla ( Lesson ) were a l s o i7hserved c Chandramchan Naidu

a al.. 1980).

Reddanna at al. (1978) studied the .effect of jn viyp

muscular electric etirnulation on euccinate and glutamate

dehydrogenasee of the tissues of ILana hexadactvla. A comparative

study of the activity of enzymes such as acid phosphatase,

alkaline phoephatase, lactic dehydrogenase, aldolase, aspartic

transaminase. alanine tranaaminase, adenosine triphosphatase and

fructose 1, 6, -diphosphatase of the skeletal muscle of frog

&ula 1' ' and toad Bufn (Schneider) were made

by Vaeantha blyanam and Shanmuga Sundaram (1983).

Since there was no report on the effect of heavy metal

toxicity on the succlnic dehydrogenase activlty levels I n LAM

the present attempt was made to study the ef i ec t of

.sublethal and medlan lethal treatments of coFper on succinic

dehydrogenase activ1t.y levels of h u he-':adactvla.

10.2 OBSEHVATI ONS

10.2.1 I&y&3 ef succinic dehvdrogenase actlvltv: . .

10.2.1.1 Succlnlc . . dehvdroeenaseactivitv-incontrol-:

Succinic dehydrogenase activity levels of liver, intestine,

kidney and muscle of Ifana he.uadactvla were studied. In the

control frog,the activity levels were relatively high in liver

(45.19) followed by intestine (34.29). kidney (29.30) and muscle

(25.28) (Values are expressed as p moles of formazon formed/g wet

tiesuedhour.

The SDH activity levels in liver. showed an increaee at boih

treatments. The percent change over control at sublethal

treatment was +129.96, +159.01, +16.80, +28.34, +32.63 at 24, 48,

72, 96 and 120 hrs respectively. In median lethal treatment, it

was found +103.62, +55.12, +89.38, +50.63, +14.33 at 24, 48, 72,

96 and 120 hrs respectively. (Table.25., Fig.25.).

Intestine showed decreased level of SLM activity at both

treatments. The percent change over control was -4.21, -10.35.

-18.56, -16.05, -23.35 at 24, 48, 72, 96 and 120 h r s re~pectiveiy

in sublethal treatment. In median lethal treatment it was found

to change by -7.31, -8.24, -29.26.-22.62, -35.68 at 24, 4b, 7 2 ,

96 and 120 hrs respectively (Table,26.,Fig.,26.,.

A gradual decline in the SDH activity was observed In the kidney

at both treatments. The percent changes over control was -5.45,

-7.41, -17.80, -24.16, -34.30 at 24. 48, 72, 96 and 120 hrs

respectively. The percent decrease over control was -6.21,

-11.99, -26.62, -37.85, -64.26 at 24, 48, 72, 96 and 120 hrs

respectively in median lethal treatment (Table 27., Fig.27 1 -

Muscle also showed decreased level of SDH actlvity at both

treatments, it was found to decrease gradually upto 72 hrs and an

increaee was observed at 96 hrs which was followed by a fall at

120 hrs of sublethal treatment. The percent change over control

was -2.67, -5.68, -16.33, -11.11, -17.50 at 24, 48, 72, 96 and

120 hrs respectively. A gradual decline in SDH activity was

observed throughout the period of atedian lethal treatment. The

percent change over control was -21.51, -23.58, -26.08, -40.04,

-41.71 st 24, 48, 72, 96 and 120 hrs respectively (Table. 28..

Fig.28. ) .

10.3 DISCUSSION

In the present investigation the succinic dehydrogenase

activity levels in control liver was very high (45.19) because of

its important art in metabolism. The SDH activity levels of

liver was greater than intestine ( 3 4 . 2 9 ) . kidney ( 2 9 . 3 0 ) , and

muscle ( 2 5 . 2 8 ) . (Values in parentheses a r e expressed as p rno:~.~

of forrnazor~ formed/g wet t ieeue/hr ) . Sirrcc liver i~ the centre

for metabolic h c t ivitie~, it& unit nletatjo1iE;ni i ~ ; high compared tc

any other tissue (Dixon and Webb 1963: Procser 1973). The higher

levels in intestine (34.29 p moles of formazon formed ,'g wet

tissuefir) next to liver may be due to it6 role in the digestion

and abeorption. Kidney showed higher levels of S W activity than

muscle. This may probably be due to its unique function in

osmoregulation and ionic regulation. This shows that these

organs have greater dependence on oxidative metabolism which

insures augmented generation of pwer which is generally needed

for the sustained discharge of the vital function of the tissue.

The elevation in the S W activity level at both treatments

in liver may be due to more absorption of oxygen to counteract

the energy loss caused by the toxicant and to detoxify the excess

metal. The increased rate of oxygen uptake to meet the energy

demand may be one of the important ways for the increase in liver

SDH activity (F'riacilla. 1985). The increase in SrlH activity may

be to meet the increased demands of energy for sustained muscular

contraction due to pesticide action (Lardy and Wellman 1952;

Chance and Williams 1955a; Chappel and Harrahoff 1967).

Increased SDH activity has been recorded in % lalla exposed

to both lethal and sublethal concentrations of lindane

(Hamalingam, 1978 1 . Suhramaniyan ( 1974 ) reported an increase in

. . the SLM activity of the liver in - fossllls exposed

to varioue concentrat,ions of saline medium.

Muscle showed low level of SI!H activity both at sublethal

and median lethal treatments. The decrease in the SW activity

might have been caused by the continuously increased muscular

activity which might have changed the metabolic pathway towards

anaerobic side to meet t.he increased and immediate energy demand.

Observations of Priscilla (1985) supports the present study. An

a1 teration in the tiseue metabolism towards an anaerobic type

caused reduction in muscle succinic dehydrogenase enzyme activity

of Ssrotharadon subjectad to sublethal cnncent.rations

of DDT and malathion (Hamalingam, 1985). It was reported in

Ghmma atrfatus that the inhibition of SDH was directly related

to anaerobic metaboliem (NataraJan 1981a). Sivaprasada Hao and

Ramana Hao (1979) reported tQe inhibition of SIN activity in the

muscles of TilaPia after the exposure to sublethal

concentration of methyl parathion. Bakthavathsalam ( 1980)

reparted inhibition of SDH activity in the muscle of Anabas

teatudineua exposed to lethal concentration of disyston and

furadan for 6 hre.

Intestine exhibited reduction in SIIH activity a t both

treatments. It may be due to the deposition of cogper and severe

damage in the histoarchitecture of t.he intestine. The heavy

metal salts being inorganic cations, can easily pass throclgh the

membrane8 and reach the inner mitochondria1 region which may

impair the enzyme system associated with the respiratory chain.

The accumulat.ion of to sic ant.^ found in the intestine might have

intoxicated the inteatinal cells, causing variation in the

succinic dehydrogenase activity levels of the tissue.

Kidney showed a continuous decline in SIN activity at both

treatments. It may be due to the severe histopathological

changes caused at the time of elimination of copper salts, for

detoxification. Kidney being an important organ in the

maintenance of t.hs ionic balance, their cells get damaged during

elimination of the metal salts leading to the low SIN activity

levels. A marked decrease in the SDH activity levels in liver

and kidney of parathion and lindane treated male rat have been

recorded (Dikshith a d., lY78b) Sivaprasada Hao and Hamana hao

(1979) reported a similar inhibition of S W activity in liver,

muscle and gill tissues of % treated with

sublethal concentration of methyl parathion for a period of 4b

hrs. The impairment of S W activity levels may be related to the

accumulation of copper salts. Heavy metals can disrupt the

energy production by the inhibition of oxygen uptake within the

cell and the disruption can occur at low levels causing severity.

leading to the death of bluegill (Ler.omls e:.:posec! tc

cadmium and zinc (Hilt.ibran, 1971 1 .

Changes in the SIjH activity at varicus treat.mentr- and

treatment periods of copper are statistically significant at 1%

level.

10.4 CONCLUSIONS

1. In liver of -,due to more absorption of

oxygen to counterzact the energy loss, SL)H actlvlty wa"

found elevated at both treatments of copper.

2 . In muscle,due to the increased muscular activity, the TCA

cycle might have been changed towards anaerobic side and

result.ed in decreased SDH activity at bot.h treatments.

3. Because of the severe histopathological lesions and tissue

damage,the enzymatic mechanism was impaired which might have

resulted in decreased SDH activity at both treatments in

inteetine and kidney.

Table.27

Effect

of

vari

ous tr

eatm

ents

and

tre

atm

ent

peri

od8

of c

o~

r

on SDH activity level

(AI mles of

formazon/g

wet

ti

ssu

ehr)

in

the

ki

dney

of

Ba

rut m

.

Each value is the

average

of 10

individual8

(X t SE),

values i

n p

aren

thes

ess

repr

esen

t pe

rcen

t change o

ver control.

Tre

atm

enta

24

Tre

atm

ent

peri

ods

(Hou

rs

48

7': 96

Sub

leth

al

26.26i 0.024

27.5050.394

24.15~0.024

22.22i0.014

19.12i0.014

(-9.45)

(-7.41)

(-17

.00)

(-24.16)

(-34

.30)

Med

ian

leth

al 27.20

t 0.019

26.14

i 0.018

21.56

t 0.041

18.21

+_ 0.041

10.40

t 0.043

(-6.21)

(-11.99)

(-26.62)

(-37.85)

(-64.26)

I-' 0

t-- Analyeis of

vari

ance

hey1

icat

ion8

9

5.0580

0.58

20

1.1658

Tre

atm

ent

2 1890.427

945.21%

1960.7003*

Tre

atm

ent x

~e

rio

d 8

912.0097

114 .

0012

236.4779*

Err

or

126

60.7420

0.4821

- - -- - -. --

-

* H

ighl

y si

gn

ific

ant

at 1%

leve

l.

Median lethal

Control

TREATFKNT PERIOD (HOURS)

Flg.25 Levels of SDH activity ( p moles of formazon formed /g wet t iswe/hr) in the l lver of Rana hexadactyla treated with sublethal and median lethal doses of coppar for various hours.

control

TREATMENT PERIOD (HOURS)

Fig. 26 Levels of SDH activity ( p moles of formazon formed /g wet tlssue /hr) in the intestine of R z hexadactyla treated with sublethal and median lethal doses of copper for varlous hours.

1

4e 7 7

Y ' t k 122

) < TRERTMENT PERIOD ( HOURS) Y 0

Fig. W Levels of SDH activlty ( p moles of formazon formed

I /g wet t i s sue /hr) in the kidney of RE hexadactyla 0 t reated with sublethal and median lethal doses of I copper for various hours.

I Medlan lethal

'Sublethal

Control

i .

I I

24 4s - - e -- is? TREATMENT PERIOD ( HOURS)

Levels of SDH actlvlty ( p m o l e s of formazon formed

/g net tlssue/hr 3 In the muscle of R z hexadactyla

treated wlth sublethal and medaan lethal doses of w r for various hours.