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ST U D Y 1:
ST U D Y 2:
ST U D I ES I N N EU R O - E N DO C R I NO LOGY :
T H E E F F E C T O F P R E - PU B E RTAL G O N A D EC TO MY O N T H E G ROWTH RAT E OF CATS.
A COMPA RAT IVE STUDY OF SE LE C T E D ASPECTS O F T H E POSSU M ( T R I C H O SURUS V U LPECU LA
K E R R ) B RA I N .
A thesis p resented i n pa rtial fu l fi lment of the requ i rements fo r the deg ree of Ma ste r o f Science i n Phys iolog y at Mas sey U n iversity .
Anthony Kett le 1983.
ABST RA C T
G on a dectomy i s the commonest surg ica l p rocedu re ca r r ied ou t in the cat , ma i n l y fo r fe rti l i ty contro l . H oweve r , the effect of g onadectomy o n body weig h t in the cat has recei ved l ittle study a l thoug h t h i s s ubject is wel l resea rched i n other species , such a s the rat . Pa rt I o f the p resent study i n v o l ved gonadectomy at 20 weeks . The cats were hou sed i n outdoor colony cag e s and g i ven food ad l i bi d u m , adju sted to leave da i l y resi d ues . Body weig h t was mea s u red weekly a nd transfo rmed to log 1
O. Fo r stat istical a n a l y s i s , d i fferences in body weight of each cat were tested by one-way a n a ly s i s of va r i a nce and seria l cova ria nce u sing the p reviou s wee k•s body weig h t as the cova riate . D i ffe rences between g roups were i n vestig ated w i th •t• tests a n d g rowth rates were stud ied by reg ression . U p to 32 wee k s o f age t h e re was no sta tistica l l y s i g n i fica nt d i ffe rence between the g rowth rates o f e n t i re ve rsus the ca stra tes i n either sex . H oweve r , when e xtended to 55 wee ks o f age p repu be rta l gonadectomy i n the fema le cat ca u sed s ig n i ficantly i n c rea sed g rowth . This was n ot obse rved for the ma le ca t .
Little i n fo rmation i s avai lable on the a na tomy of the b r a i n of the
Au stra l a s i a n possum (Trichosu rus vu l pecu l a ) . Pa rt 1 1 of the p resent study a i ms at p resen t i n g a simple description o f the possum hy potha lamus viewed in th ree plan es of section and concentra t i n g on some of the fi b re t racts w h i c h a re clea r l y v i s i b l e . T he ma i n fi n d i n g s were t h a t the
mammi l l otha lamic t ract appea r s i n a simi la r pos ition to that as seen i n other mamma l s such a s the rat , cat , and sheep , whi le the fo rnix a ppea rs much steepe r i n its d e scent i nto the ante r i or h y potha l u mus . In add ition , there i s desc r i bed a fi b re t ract ema nating from t he optic chia sma a n d pa ssing to the ca u d a l pa rt o f the pa rave n t ricu l a r n u c l eus . Th i s t ract ha s not been desc r i bed i n oth e r mamma l s , s uch as th e rat , cat , and sheep .
P REFA C E
I n 1977 M s E Somme rvi l l e and D r M Ta rtte l i n o f Massey U n i ve rsity
con d ucted a p rel i m i na ry study on the effect of pre-p u be rta l g onadectomy on the g rowth rate of cats . The resu l ts of t h i s p re l i m i n a ry study were viewed w i t h cau tion due to a s u spected n u t r i t iona l i n a de quacy in the d iet . The p re se n t study was therefo re u nderta ken u s i ng a n experimenta l ca n n ed cat d iet p roduced b y J Wattie C a n n e r ies Ltd . , which had a n i n c reased prote i n l e ve l . T he resu l ts o f t h i s study were compa red to the fo rme r investigation .
Pa rt 11 o f t h i s thes i s a rose from a person a l i nterest i n the New Zea la n d pos s u m ( T r ichosu ru s vulpecu la ) a n d w a s ca r ried out d u ri ng t h e l a ter pa rt of the yea r when the dai ly work i n vol vement for the ca t g rowth study was red u ced .
The two stud ies a re qu ite u n re la ted except i n so fa r a s i t was hoped to be able to i d e n t i fy a defin it ive vent ro-med ia l hy potha lamu s ( VM H ) i n the hypotha l a m u s of the possum . T he VMH reg ion in cats has been im p l i cated i n the con t rol of g rowth , thus p roviding a tentative l i n k between the two stu d i es .
The title 'possum' fo r the New Z e a l a n d species of T richos u ru s v u l pecu la and 'oppo s s u m ' fo r the Ame rica n , D i de l p h i s v i rg in iana w a s adopted in l i ne w ith a g row i ng convention among s t i n vestigato r s in the fie l d , a l thoug h the re i s s t i 11 con s i de rable cont rove rsy ove r the u se of these titles a s commen ted on i n a recent edition o f Possum Post ( Possum Post N o . 2 : 2 Dece mbe r 1 9 8 0 ) .
AC K N OWLEDGEM E N T S
I a m indebted t o D r . M . F . Ta rttel i n for h i s exten sive h e l p ,
encou ragement , and s u pervi s ion t h roughout the study , pa rticu l a r l y for h i s he l p with t h e sta tistics section , t h e possum h i stology , a nd the g ra ph i c wo rk .
I a m a l so g ra tefu l fo r the help g i ven with the statistics by P rofessor R . E . Mu n ford , P rofessor o f Physiology a n d Anatomy , i n whose depa rtme n t t h i s wo rk w a s ca r ried out .
Mr M . J . B i rt les k i n d l y p rov ided expe rt tec h n ica l ass ista nce w i th the possum h i s tology and put the eq u i pment of h i s l a borato ry a t my d i sposa l , w h i l e Mrs U Da rel l , Mr E . O rmsby , Ms E Somme rv i l l e , Mi ss S Me r ri tt , a n d Mi s s C Co l i in s , helped m e with t h e ma nagement of the ca t colony i n the Sma l l A n i m a l Production U n it of Ma s sey U n iversity .
The possums were k i n d l y t rapped b y Mr a n d Mrs R. McCammon a n d Mrs E . B r i s to l .
I a l so ac k now ledge the sta ff of J . Wa ttie Canne ries Ltd . , i n pa rticul a r M rs J Newe l I a n d Mr B . T ra s s fo r thei r h e l p i n compoundi ng the C X 9 ca n ned cat diet and in supp l y i ng the enti re d i et free of charge .
I would l i ke to tha n k M r T . Law fo r the p hotog ra phy and Wo rdcom fo r ty p i ng of the ma n u sc r i p t .
Anthony Kettle 1 98 3
TAB LE O F C O NT E N T S
T itle Abs t ract P re face
Acknow l edgements Table of Contents
List of Fig u res ( Pa rt I ) List of Ta b le s ( Pa rt I ) List of Fig u re s ( Pa rt 11) List of Ta b le s ( Pa rt 11)
Pa rt I The e ffect of p repuberta l gona dectomy o n the g rowth rate of cats I nt roduction
Ma te r i a l s and Method s B iomet rica l Con s i de ration s Resu l ts - Body Weight
- Diet
D i scu ssion a n d Conc lusions Appe n d i x 1 .
1 a . 1 b . Appendix 2 . A ppen d i x 3 .
A p pe n d i x 4 . Refe rences Pa rt 11
I ntroduction
The Cat pens Side Eleva t i on F ront E l evation
Descriptions of p ha rmacolog ica l agents employed
Analysis of C X 9 N P a s s u ppl ied by J . Wattie C a n n e ries Ltd Abst ract from J . Physiol 3 1 9 : 5 5 -5 6 P
A Compa rative study o f selected a spects of the b r a i n of the possum
( T r ichosu r u s v u l pecu l a )
Mate r i a l s a n d Methods
- Anaesthesia - S u rgery - H i stolog y
- Age Dete rmination Resu l t s and D i sc u ss ion o f A naesthesia Resu l ts a n d D i s cussion of Age Ana l y s i s
Resu l t s a nd D i sc u ss ion of a n i nvestigation i nto t h e use of the ste reotaxic i n st ru ment fo r l ocati ng i n ternal neural st ructu res with i n the
i i i i i i v
V
v i i v i i i i x
X
2 4 7 8 1 6 1 8 2 1 2 2 2 3 2 4 2 6
2 7 2 9 3 3
34 39 3 9 3 9 40 40 42 43 44
possum b ra i n .
The meas u rement system for analysis o f possum h i stology
44
Anterior - Poste rior mea s u rements 44
- with refe rence to the s u p raoptic nucleu s 44 - with refe rence to the mamm i l lotha lamic t ract ( MTT ) 46
Late ra l mea su rements 48
Mea su remen t of Structures with i n the Possum b ra i n 4 9 ·
Summa ry 5 4
Resu lts a n d D i scussion of the microa natomica l study o f a 5 5 se lection o f fib re sta i ned sections i n th ree ste reotaxic p l anes
A p pendix 1 .
A p pendix 2 . Appendix 3 . A p pend i x 4 . Refe rences .
A nterior - Poste rior H o ri zonta l
Sag itta l D i scussion
Embedding p rocess fo r possum b ra i n mate ria l .
B ra i n h i sto logy method s
Sta i n i ng so lutions fo r h i stol ogy
Proced u re fo r sta i n i ng possum teeth section s
5 8 6 9 7 5 8 3 8 4
8 5 86 8 7 8 8
L I ST O F F I G U R E S ( PART I ) Fig u re la
Fig u re lb
Fig u re 2
Fig u r e 3
Fig u re 4
G raph of body weig h t versus standa rd dev iation for cat g rowth data .
G raph of loga rithm body weig ht versus standard deviation fo r cat g rowth data
Scatte rg ram of a l l mea s u red unt ra n s formed body weight data.
G raph relating body weight in loga ri thmic tran sformation of a l l treatment g roups d u r i ng t he 3 2 week study pe riod
G raph relating body weight in loga rithm i c transformation of a l l t reatment g roups during t he 3 2 week per iod of t he 1 9 74 p rel imina ry study .
9
9
1 0
1 1
1 2
L I S T O F TAB LES ( PART I ) Tab l e 1
Tab le 2 Tab le 3
Tab l e 4a
Ta b l e 4b
Tab le 5
Ta b l e 6
Tab le 7
S umma ry o f cat bi rth d a ta
S umma ry o f k i tten t reatment g rou p s
S umma ry o f t h e tran sfo rmed means a n d the resu l ts of the A N OVAR a n d A N COVAR a n a lysis
4
5 13
' t ' test res u l t s on nonadj u sted mea n s d u r i n g 1 4 pe riods when AN OVAR showed a sig n i ficant d i ffe rence
' t ' test res u l ts on adju sted mea ns du r i n g 1 5 pe riods when A N C OVAR s howed a s ig n i ficant d i ffe rence
Analysis of pooled data from the th ree a n a l y se s of the can ned cat d iet
Mean Body Weig h t ( g ) of enti re cats at 24 wee ks of ag e .
Recommended leve l s of p rotein and fat i n a cat d i et a s exp ressed as pe rcentages o f the d ry weight .
1 6
1 9
1 9
L I S T O F F I G U RES ( PA RT 11) Fig u re
Fig u re 2
Fig u re 3
Figu re 4
Fig u re 5
T h e re lation s h i p of mamma l s 35
A compa ri son o f the denta r y featu res 36 of polyprotodont and d i p rotodont marsupia l s
Anterior - poste rior mea s u rement of 4 4 - 45 st,Jp raoptic n uc leus
Anterior - poste rior mea s u rement of 46 - 47 ma m m i l lotha lamic tract
La te ra l mea su rement of the mammi l lothalamic 48 - 49 tract .
L I ST O F T ABLES ( PA RT 11)
Tab l e 1
Tab le 2
Ta b le 3
Tab le 4 Tab le 5 T a b l e 6
T a b l e 7
T a b l e 8
A compa ri son o f the nome n c lature u sed to desc r i be the g rou p s o f l iv i n g mamma l s
Esti mate o f age o f possums u sed i n the study
S h r i n kage estimates fo r poss um sections
Ante rior-poste r i o r mea s u rements Late ra l mea su rements
Ste reotaxic co-o rd i nates of selected structu res
S O N and M T T re ferenced to externa l l a nd ma rks ( I nter-a u ral Li n e )
Sepa ration ( m i c ron s ) betwee n each
p late , corrected to wet b ra i n measu rement .
34
43
4 6
4 9 5 0 5 0
53
5 6
