The central questions of the present study were:1. does base line hormonal state determine agonistic behavior in male-male encounters? 2. does agonistic behavior affect hormonal state? Such an interrelationship between agonistic behavior and hormonal processes might serve as a regulatory system for behavior, in which hormonal changes due to agonistic experiences mediate behavioral changes after these experiences. The above questions were asked inrelation to gonadal and adrenal hormones. ...Zie: General discussio

Schuurman, Teunis

English

ARTS repository - University of Groningen

   University of GroningenEndocrine processes underlying victory and defeat in the male ratSchuurman, TeunisIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1981Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Schuurman, T. (1981). Endocrine processes underlying victory and defeat in the male rat. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 07-06-2022C H A P T E R  V IG E N E R A L  D I S C U S S I O NT h e  c e n t r a l  q u e s t  i o n s  o f  t h e  p r e s e n t  s t u d y  \ ^ r e r e :' I  .  d o e s  b a s e  l i n e  h o r m o n a l  s t a t e  d e t e r m i n e  a q o n i s t i c  b e h a v i o r  i nm a l e - m a l e  e n c o u n t e r s ?2 .  d o e s  a g o n i s t i c  b e h a v i o r  a f f e c t  h o r m o n a l  s t a t e ?Such an  in te r re la t ionsh ip  be tween agon is t i c  behav io r  and hormona lp r o c e s s e s  m i g h t  s e r v e  a s  a  r e g u l a t o r y  s y s t e m  f o r  b e h a v í o r ,  i n  w h i c hh o r m o n a l  c h a n g e s  d u e  t o  a g o n i s t i c  e x p e r i e n c e s  m e d i a t e  b e h a v i o r a lc h a n g e s  a f t e r  t h e s e  e x p e r i e n c e s .  T h e  a b o v e  q u e s t i o n s  w e r e  a s k e d  i nr e l a t i o n  t o  g o n a d a l  a n d  a d r e n a l  h o r m o n e s .W i t h  r e s p e c t  t o  t h e  f i r s t  a s p e c L  o f  t h e  p r o p o s e d  h o r m o n e - b e h a v i o ri n t e r r e l a t i o n s h i p ,  t h e  p r e s e n t  s t u d y  g Í v e s  e v í d e n c e  t h a t  b a s e  l i n ep l a s m a  t e s t o s t e r o n e  ( T )  c o n c e n t r a t i o n  i s  a  f a c t o r  t h a t  d e t e r m i n e sL h e  a m o u n t  o f  a g g r e s s i v e  b e h a v i o r  i n  m a l e r n a l e  e n c o u n t e r s  ( t h e  c a s -t r a t i o n  e x p e r i m e n t  i n  C h a p t e r  I I ) .  F u r t h e r ,  a l s o  c o r r e l a t i o n a l  e v i -d e n c e  f o r  t h i s  b e h a v i o r a l  e f f e c t  o f  b a s e  l i n e  T  i s  g i v e n  ( C h a p t e rT I I ) .  P r o b a b l y  T  a f f e c t s  o n l y  t h e  a g g r e s s i v e  c o m p o n e n t s  o f  a g o n i s t i cb e h a v i o r  a n d  n o t  t h e  d e f e n s i v e  c o m p o n e n t s .  N o  e v i d e n c e  w a s  o b t a i n e dt h a t  b a s e  l i n e  c o r t i c o s t e r o n e  ( C )  c o n c e n t r a t i o n  a f f e c t s  a g g r e s s i v ea n d / o r  d e f e n s i v e  b e h a v i o r .W i t h  r e s p e c t  t o  t h e  s e c o n d  q u e s L i o n ,  L h e  p r e s e n t  s t u d y  s h o w s  t h a ta  . . i - - l  ê  . ê r i ^ , , .  À ^ € ^ ^  r  t ^ ^ - ^ ^ ^ ^ ^  L a e e  I  i n p  n l r q m a  T  ^ ^ h ^ ó h t s r . f  i ^ nA  D  r r r B l g  J € l  I U U D  U r l  E d t  r  L U l l L g l l L l d L  L u r r t9 6Lc behavior inrr and hormonallhavior, in whichrte behavioralrs r{7ere asked inI hormone-behaviorr  that  base l inelhat determines)unters (the cas-rrrelational evi-given (Chapterrents of  agonist ic3nce was obtainedEects aggressivet study shows thatT concentrat ion,and it is thinkable that this lowered base line T contributes tothe behavioral changes due to defeat (Chapter IV). On the other handin most  rats  a s ingle defeat  does not  lead to a l tered base l ine Cconcentrations. In Chapter V the hypothesis is put forward that theacute,  t ransient  C e levat íons dur ing male-male encountêrs contr i -bute to behavioral changes. In other words hormones might rnediatethe effects of agonistic encounters on behavior in different ways:l .  by a more or  less chronical ly  a l tered hormone base l ine concen-tration. Probably this way takes at least some hours.2.  by rapid,  t ransient  hormonal  responses to agonist ic  encounters.The ef fects of  these resDonses or  behavior  mav be acute.FuËure experiments have to give the final ans\irer whether these hor-monal changes due to agonistic experiences indeed play a role inthe real izat ion of  changes in agonist ic  behavior .  Techniques thatmay prevent or exaggerate the above hormonal changes are a goodtoo l  f o r  t h i s  ( see  Leshne r ,  1980 ) .Interest ingly ,  some defeated rats regained normal  levels .ofaggressive and defensive behavior  wi th in one week af ter  defeat ,whereas other losers did not so. Also inter-individual differencesin the hormonal  changes af ter  defeat  were observed.  For  example,part of defeated rats showed hypoglycemia during a lost combat andin some rats chronically elevated C levels $rere measured one weekaf ter  defeat .  Maybe that  these and other  hormonal  changes due torepeated 'psychological"  s t ress might  p lay a ro le in  the et ío logyof  some st ress-re lated d iseases in  men and animals (see e.g.  Henryand Cassel ,  1969;  Iams et  a l  .  1979;  Scklar  and Anisman,  1979).9 7

Endocrine processes underlying victory and defeat in the male rat

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 University of Groningen
Endocrine processes underlying victory and defeat in the male rat
Schuurman, Teunis
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from
it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date:
1981
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Schuurman, T. (1981). Endocrine processes underlying victory and defeat in the male rat s.n.
Copyright
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Download date: 10-02-2018
C H A P T E R  V I
G E N E R A L  D I S C U S S I O N
T h e  c e n t r a l  q u e s t  i o n s  o f  t h e  p r e s e n t  s t u d y  \ ^ r e r e :
' I  
.  d o e s  b a s e  l i n e  h o r m o n a l  s t a t e  d e t e r m i n e  a q o n i s t i c  b e h a v i o r  i n
m a l e - m a l e  e n c o u n t e r s ?
2 .  d o e s  a g o n i s t i c  b e h a v i o r  a f f e c t  h o r m o n a l  s t a t e ?
Such an  in te r re la t ionsh ip  be tween agon is t i c  behav io r  and hormona l
p r o c e s s e s  m i g h t  s e r v e  a s  a  r e g u l a t o r y  s y s t e m  f o r  b e h a v í o r ,  i n  w h i c h
h o r m o n a l  c h a n g e s  d u e  t o  a g o n i s t i c  e x p e r i e n c e s  m e d i a t e  b e h a v i o r a l
c h a n g e s  a f t e r  t h e s e  e x p e r i e n c e s .  T h e  a b o v e  q u e s t i o n s  w e r e  a s k e d  i n
r e l a t i o n  t o  g o n a d a l  a n d  a d r e n a l  h o r m o n e s .
W i t h  r e s p e c t  t o  t h e  f i r s t  a s p e c L  o f  t h e  p r o p o s e d  h o r m o n e - b e h a v i o r
i n t e r r e l a t i o n s h i p ,  t h e  p r e s e n t  s t u d y  g Í v e s  e v í d e n c e  t h a t  b a s e  l i n e
p l a s m a  t e s t o s t e r o n e  ( T )  c o n c e n t r a t i o n  i s  a  f a c t o r  t h a t  d e t e r m i n e s
L h e  a m o u n t  o f  a g g r e s s i v e  b e h a v i o r  i n  m a l e r n a l e  e n c o u n t e r s  ( t h e  c a s -
t r a t i o n  e x p e r i m e n t  i n  C h a p t e r  I I ) .  F u r t h e r ,  a l s o  c o r r e l a t i o n a l  e v i -
d e n c e  f o r  t h i s  b e h a v i o r a l  e f f e c t  o f  b a s e  l i n e  T  i s  g i v e n  ( C h a p t e r
T I I ) .  P r o b a b l y  T  a f f e c t s  o n l y  t h e  a g g r e s s i v e  c o m p o n e n t s  o f  a g o n i s t i c
b e h a v i o r  a n d  n o t  t h e  d e f e n s i v e  c o m p o n e n t s .  N o  e v i d e n c e  w a s  o b t a i n e d
t h a t  b a s e  l i n e  c o r t i c o s t e r o n e  ( C )  c o n c e n t r a t i o n  a f f e c t s  a g g r e s s i v e
a n d / o r  d e f e n s i v e  b e h a v i o r .
W i t h  r e s p e c t  t o  t h e  s e c o n d  q u e s L i o n ,  L h e  p r e s e n t  s t u d y  s h o w s  t h a t
a  . . i - - l  ê  . ê r i ^ , , .  À ^ € ^ ^  r  t ^ ^ - ^ ^ ^ ^ ^  L a e e  I  i n p  n l r q m a  T  ^ ^ h ^ ó h t s r . f  i ^ nA  D  r r r B l g  J € l  I U U D  U r l  E d t  r  L U l l L g l l L l d L  L u r r t
9 6
Lc behavior in
rr and hormonal
lhavior, in which
rte behavioral
rs r{7ere asked in
I hormone-behavior
r  that  base l ine
lhat determines
)unters (the cas-
rrrelational evi-
given (Chapter
rents of  agonist ic
3nce was obtained
Eects aggressive
t study shows that
T concentrat ion,
and it is thinkable that this lowered base line T contributes to
the behavioral changes due to defeat (Chapter IV). On the other hand
in most  rats  a s ingle defeat  does not  lead to a l tered base l ine C
concentrations. In Chapter V the hypothesis is put forward that the
acute,  t ransient  C e levat íons dur ing male-male encountêrs contr i -
bute to behavioral changes. In other words hormones might rnediate
the effects of agonistic encounters on behavior in different ways:
l .  by a more or  less chronical ly  a l tered hormone base l ine concen-
tration. Probably this way takes at least some hours.
2.  by rapid,  t ransient  hormonal  responses to agonist ic  encounters.
The ef fects of  these resDonses or  behavior  mav be acute.
FuËure experiments have to give the final ans\irer whether these hor-
monal changes due to agonistic experiences indeed play a role in
the real izat ion of  changes in agonist ic  behavior .  Techniques that
may prevent or exaggerate the above hormonal changes are a good
too l  f o r  t h i s  ( see  Leshne r ,  1980 ) .
Interest ingly ,  some defeated rats regained normal  levels .of
aggressive and defensive behavior  wi th in one week af ter  defeat ,
whereas other losers did not so. Also inter-individual differences
in the hormonal  changes af ter  defeat  were observed.  For  example,
part of defeated rats showed hypoglycemia during a lost combat and
in some rats chronically elevated C levels $rere measured one week
af ter  defeat .  Maybe that  these and other  hormonal  changes due to
repeated 'psychological"  s t ress might  p lay a ro le in  the et ío logy
of  some st ress-re lated d iseases in  men and animals (see e.g.  Henry
and Cassel ,  1969;  Iams et  a l  .  1979;  Scklar  and Anisman,  1979).
9 7


University of Groningen

   University of GroningenEndocrine processes underlying victory and defeat in the male ratSchuurman, TeunisIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1981Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Schuurman, T. (1981). Endocrine processes underlying victory and defeat in the male rat. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 12-11-2019C H A P T E R  V IG E N E R A L  D I S C U S S I O NT h e  c e n t r a l  q u e s t  i o n s  o f  t h e  p r e s e n t  s t u d y  \ ^ r e r e :' I  .  d o e s  b a s e  l i n e  h o r m o n a l  s t a t e  d e t e r m i n e  a q o n i s t i c  b e h a v i o r  i nm a l e - m a l e  e n c o u n t e r s ?2 .  d o e s  a g o n i s t i c  b e h a v i o r  a f f e c t  h o r m o n a l  s t a t e ?Such an  in te r re la t ionsh ip  be tween agon is t i c  behav io r  and hormona lp r o c e s s e s  m i g h t  s e r v e  a s  a  r e g u l a t o r y  s y s t e m  f o r  b e h a v í o r ,  i n  w h i c hh o r m o n a l  c h a n g e s  d u e  t o  a g o n i s t i c  e x p e r i e n c e s  m e d i a t e  b e h a v i o r a lc h a n g e s  a f t e r  t h e s e  e x p e r i e n c e s .  T h e  a b o v e  q u e s t i o n s  w e r e  a s k e d  i nr e l a t i o n  t o  g o n a d a l  a n d  a d r e n a l  h o r m o n e s .W i t h  r e s p e c t  t o  t h e  f i r s t  a s p e c L  o f  t h e  p r o p o s e d  h o r m o n e - b e h a v i o ri n t e r r e l a t i o n s h i p ,  t h e  p r e s e n t  s t u d y  g Í v e s  e v í d e n c e  t h a t  b a s e  l i n ep l a s m a  t e s t o s t e r o n e  ( T )  c o n c e n t r a t i o n  i s  a  f a c t o r  t h a t  d e t e r m i n e sL h e  a m o u n t  o f  a g g r e s s i v e  b e h a v i o r  i n  m a l e r n a l e  e n c o u n t e r s  ( t h e  c a s -t r a t i o n  e x p e r i m e n t  i n  C h a p t e r  I I ) .  F u r t h e r ,  a l s o  c o r r e l a t i o n a l  e v i -d e n c e  f o r  t h i s  b e h a v i o r a l  e f f e c t  o f  b a s e  l i n e  T  i s  g i v e n  ( C h a p t e rT I I ) .  P r o b a b l y  T  a f f e c t s  o n l y  t h e  a g g r e s s i v e  c o m p o n e n t s  o f  a g o n i s t i cb e h a v i o r  a n d  n o t  t h e  d e f e n s i v e  c o m p o n e n t s .  N o  e v i d e n c e  w a s  o b t a i n e dt h a t  b a s e  l i n e  c o r t i c o s t e r o n e  ( C )  c o n c e n t r a t i o n  a f f e c t s  a g g r e s s i v ea n d / o r  d e f e n s i v e  b e h a v i o r .W i t h  r e s p e c t  t o  t h e  s e c o n d  q u e s L i o n ,  L h e  p r e s e n t  s t u d y  s h o w s  t h a ta  . . i - - l  ê  . ê r i ^ , , .  À ^ € ^ ^  r  t ^ ^ - ^ ^ ^ ^ ^  L a e e  I  i n p  n l r q m a  T  ^ ^ h ^ ó h t s r . f  i ^ nA  D  r r r B l g  J € l  I U U D  U r l  E d t  r  L U l l L g l l L l d L  L u r r t9 6Lc behavior inrr and hormonallhavior, in whichrte behavioralrs r{7ere asked inI hormone-behaviorr  that  base l inelhat determines)unters (the cas-rrrelational evi-given (Chapterrents of  agonist ic3nce was obtainedEects aggressivet study shows thatT concentrat ion,and it is thinkable that this lowered base line T contributes tothe behavioral changes due to defeat (Chapter IV). On the other handin most  rats  a s ingle defeat  does not  lead to a l tered base l ine Cconcentrations. In Chapter V the hypothesis is put forward that theacute,  t ransient  C e levat íons dur ing male-male encountêrs contr i -bute to behavioral changes. In other words hormones might rnediatethe effects of agonistic encounters on behavior in different ways:l .  by a more or  less chronical ly  a l tered hormone base l ine concen-tration. Probably this way takes at least some hours.2.  by rapid,  t ransient  hormonal  responses to agonist ic  encounters.The ef fects of  these resDonses or  behavior  mav be acute.FuËure experiments have to give the final ans\irer whether these hor-monal changes due to agonistic experiences indeed play a role inthe real izat ion of  changes in agonist ic  behavior .  Techniques thatmay prevent or exaggerate the above hormonal changes are a goodtoo l  f o r  t h i s  ( see  Leshne r ,  1980 ) .Interest ingly ,  some defeated rats regained normal  levels .ofaggressive and defensive behavior  wi th in one week af ter  defeat ,whereas other losers did not so. Also inter-individual differencesin the hormonal  changes af ter  defeat  were observed.  For  example,part of defeated rats showed hypoglycemia during a lost combat andin some rats chronically elevated C levels $rere measured one weekaf ter  defeat .  Maybe that  these and other  hormonal  changes due torepeated 'psychological"  s t ress might  p lay a ro le in  the et ío logyof  some st ress-re lated d iseases in  men and animals (see e.g.  Henryand Cassel ,  1969;  Iams et  a l  .  1979;  Scklar  and Anisman,  1979).9 7

The central questions of the present study where:
1. does base line hormonal state determine agonistic behavior in male-male encounters?
2. does agonistic behavior affect hormonal state?
Such an interrelationship between agonistic behavior and hormonal processes might serve as a regulatory system for 
behavior, in which hormonal changes due to agonistic experiences mediate behavioral changes after these experiences. The above questions were asked in
relation to gonadal and adrenal hormones. ...

Zie: General discussion

Schuurman, Teunis,

University of Groningen Digital Archive

   University of GroningenEndocrine processes underlying victory and defeat in the male ratSchuurman, TeunisIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:1981Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Schuurman, T. (1981). Endocrine processes underlying victory and defeat in the male rat. s.n.CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 30-10-2023C H A P T E R  V IG E N E R A L  D I S C U S S I O NT h e  c e n t r a l  q u e s t  i o n s  o f  t h e  p r e s e n t  s t u d y  \ ^ r e r e :' I  .  d o e s  b a s e  l i n e  h o r m o n a l  s t a t e  d e t e r m i n e  a q o n i s t i c  b e h a v i o r  i nm a l e - m a l e  e n c o u n t e r s ?2 .  d o e s  a g o n i s t i c  b e h a v i o r  a f f e c t  h o r m o n a l  s t a t e ?Such an  in te r re la t ionsh ip  be tween agon is t i c  behav io r  and hormona lp r o c e s s e s  m i g h t  s e r v e  a s  a  r e g u l a t o r y  s y s t e m  f o r  b e h a v í o r ,  i n  w h i c hh o r m o n a l  c h a n g e s  d u e  t o  a g o n i s t i c  e x p e r i e n c e s  m e d i a t e  b e h a v i o r a lc h a n g e s  a f t e r  t h e s e  e x p e r i e n c e s .  T h e  a b o v e  q u e s t i o n s  w e r e  a s k e d  i nr e l a t i o n  t o  g o n a d a l  a n d  a d r e n a l  h o r m o n e s .W i t h  r e s p e c t  t o  t h e  f i r s t  a s p e c L  o f  t h e  p r o p o s e d  h o r m o n e - b e h a v i o ri n t e r r e l a t i o n s h i p ,  t h e  p r e s e n t  s t u d y  g Í v e s  e v í d e n c e  t h a t  b a s e  l i n ep l a s m a  t e s t o s t e r o n e  ( T )  c o n c e n t r a t i o n  i s  a  f a c t o r  t h a t  d e t e r m i n e sL h e  a m o u n t  o f  a g g r e s s i v e  b e h a v i o r  i n  m a l e r n a l e  e n c o u n t e r s  ( t h e  c a s -t r a t i o n  e x p e r i m e n t  i n  C h a p t e r  I I ) .  F u r t h e r ,  a l s o  c o r r e l a t i o n a l  e v i -d e n c e  f o r  t h i s  b e h a v i o r a l  e f f e c t  o f  b a s e  l i n e  T  i s  g i v e n  ( C h a p t e rT I I ) .  P r o b a b l y  T  a f f e c t s  o n l y  t h e  a g g r e s s i v e  c o m p o n e n t s  o f  a g o n i s t i cb e h a v i o r  a n d  n o t  t h e  d e f e n s i v e  c o m p o n e n t s .  N o  e v i d e n c e  w a s  o b t a i n e dt h a t  b a s e  l i n e  c o r t i c o s t e r o n e  ( C )  c o n c e n t r a t i o n  a f f e c t s  a g g r e s s i v ea n d / o r  d e f e n s i v e  b e h a v i o r .W i t h  r e s p e c t  t o  t h e  s e c o n d  q u e s L i o n ,  L h e  p r e s e n t  s t u d y  s h o w s  t h a ta  . . i - - l  ê  . ê r i ^ , , .  À ^ € ^ ^  r  t ^ ^ - ^ ^ ^ ^ ^  L a e e  I  i n p  n l r q m a  T  ^ ^ h ^ ó h t s r . f  i ^ nA  D  r r r B l g  J € l  I U U D  U r l  E d t  r  L U l l L g l l L l d L  L u r r t9 6Lc behavior inrr and hormonallhavior, in whichrte behavioralrs r{7ere asked inI hormone-behaviorr  that  base l inelhat determines)unters (the cas-rrrelational evi-given (Chapterrents of  agonist ic3nce was obtainedEects aggressivet study shows thatT concentrat ion,and it is thinkable that this lowered base line T contributes tothe behavioral changes due to defeat (Chapter IV). On the other handin most  rats  a s ingle defeat  does not  lead to a l tered base l ine Cconcentrations. In Chapter V the hypothesis is put forward that theacute,  t ransient  C e levat íons dur ing male-male encountêrs contr i -bute to behavioral changes. In other words hormones might rnediatethe effects of agonistic encounters on behavior in different ways:l .  by a more or  less chronical ly  a l tered hormone base l ine concen-tration. Probably this way takes at least some hours.2.  by rapid,  t ransient  hormonal  responses to agonist ic  encounters.The ef fects of  these resDonses or  behavior  mav be acute.FuËure experiments have to give the final ans\irer whether these hor-monal changes due to agonistic experiences indeed play a role inthe real izat ion of  changes in agonist ic  behavior .  Techniques thatmay prevent or exaggerate the above hormonal changes are a goodtoo l  f o r  t h i s  ( see  Leshne r ,  1980 ) .Interest ingly ,  some defeated rats regained normal  levels .ofaggressive and defensive behavior  wi th in one week af ter  defeat ,whereas other losers did not so. Also inter-individual differencesin the hormonal  changes af ter  defeat  were observed.  For  example,part of defeated rats showed hypoglycemia during a lost combat andin some rats chronically elevated C levels $rere measured one weekaf ter  defeat .  Maybe that  these and other  hormonal  changes due torepeated 'psychological"  s t ress might  p lay a ro le in  the et ío logyof  some st ress-re lated d iseases in  men and animals (see e.g.  Henryand Cassel ,  1969;  Iams et  a l  .  1979;  Scklar  and Anisman,  1979).9 7

Endocrine processes underlying victory and defeat in the male rat

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