dire ctly) .
( 3 ) Pr olactin
Ronnekle iv and McCann
( 1 975 )reported that olfact ory bulbectonzy
or cranial cervical ganglionecto!I{Y' lowere d serum prolactin leve ls in
male rats .
They conc lude d that the pineal g land, or it s principles ,
normal� st imulated the re lease of prolac t in from untrea te d c ontrol
animals , and that this st imulation was induce d by olfac tory and visual
input to the pine a l gland. Unfortunate ly, all the ir blood a ample s
were obtained during ether anaes the s ia, s o the effe cts of this s tress on prolactin re le ase may have be e n c o nfounded with
th8
s urgicaltre atme nts. As pointed out by the authors , this objection is particularly valid since the e ffe ct of ether stress may have be e n
e ntire ly depe nde nt on the ability o f a n aniw.al to sme ll the anae s the t ic , and this alone m ight ac c o u nt f o r the lower prolactin leve ls in anosmic
rat s .
In the present experi:ne nt olfactory bulbe cto�ey did no t c ause
a� change in prolact in levels . Howe ver cranial cervical ganglionecto�ey induced an ele vation of plasma prolactin levels and an almost c omplete
loss of the annual seas onal rhythmic fluctuat ions in leve ls of this
hormone . It is presumed that the very s imilar re s ults obtair� d from rams which had bee n olfactory bulbe ctomize d as we ll as ganglionectomized, was the result of cranial cervical ganglio nectol'Il'J alone .
Goats which had bee n cranial cervical ganglione c t omiz e d in the
winter experie nced an e levat ion of the ir plas w� prolactin leve ls before unoperated c o ntrol animals and had s ignificantly higher leve ls for three s ucces s ive months ; however both groups of goats had s imilar midsummer leve ls ( H. Buttle , pers onal c ommunication) . Although group size was s mall ( n =
3 ) ,
the s e preliminary observations from goats were s imilar to t hose obtained from rams in Experime nt 4.I f the pineal gland is an important regulator of prolactin release in rams , as it is pres umed t o be in rats and hamsters ( Re iter,
1 974�) ,
the n its major role c o uld be as an inhibitor of prolactinsecre tion during winter, be cause pineal activity would be greatest during the period of shorte ned daily phot operiods (Re iter,
1 974�) .
Although it c ontras ts with the earlier mentioned c onc lus ions of Ronnekle iv and McCann (1 975 ) ,
the latte r hypothes is was supported by the e levated plasma prolactin levels rec orded during winter from1 70
cranial cerv ic al ganglione ctomized rams . Furthe r, this re s ult
indicate d t hat an intact sympathe t ic nervoU3 sys tem normally provide s the ne ural pathways by which the pineal gland re ce ives s timuli
ne c e s s ary for its inhibito� influe nce over prolactin re le ase .
Aut opsy data which showe d that cranial cerv ical ganglione c t o� reduce d p ine al activ ity, prov ide d further s upp ort for the above 1�pothes is .
T hU3 the results from ganglione ctomized rams in t he pre s e nt s tuqy implicate d the pine al gland as having a major role i n re gulat ing t he s e as onal changes in plasma prolact in leve ls re corded i n Experime nt 3 1 and i n the photoperiodic control of prolact i n re lease in rams
reporte d by Fe lletier
( 1 973 ) .
(4)
DataC omparison of the res ults for t he s e me n data with those
obtaine d from aut opsy material, he lpe d to c larify t he nature of gonadal
re s ponses t o the surgical treatments . T owards the e nd of the experiment and at aut opsy, operated rams , in particular those which had undergone both operat ions
(
BulbX/
GanglionX)
, te nde � to have highe r value s for i ndice s of s pe rmato z oal production t han the c ontrol rams . The s e parameters inc lude d spermat o z oa per e jaculate , spermat oz oalc. once ntrat ion and mot ility in seme n, tes t ic ular and epidiqymal we ight s ,
a nd seminiferous tubule diameters . On the other hand, untre ated rams
had higher me an value s for variable s as soc iat e d with acce ss ory gland functio n, for example : seminal fruct ose leve ls , seminal ves icular we ights , and seminal ve s ic ular fructose conte nts and c o nce ntrat ions .
Evidence of a higher leve l of s permato@e nic activity i�
s urgical� tre ate d rams , t o ge ther with the higher output of LH i n the s e animals , supporte d the view that the operations s t imulated gonadal activity by i ncre as i ng gonadotrophin se cretion. This finding also was c o ns iste nt with the the or.y t hat c ranial cervical ganglionecto� reduced the antigo nadotrophio act ivity of the pineal gland. The
e ffe cts of o lfactory bulbe c t oll\Y were unclear, except whe n c ombined with cranial cerv ical gangli one cto�, in whic h case it appeare d t o ampli� s om of t he e ffects of the lat ter treatme nt .
Re duced acc e s s ory gland function i n the operated rams c orre sponde d with lowe re d seminal ve s icular we ights and secre tion v olume s rec orded from anosmic male mice by Whit te n
( 1 956 ) .
Furthermore Sorre nt ino , Re iter and Schalch( 1 971 ) suggested
t hat olfact ory bulbe c t o� andcranial cervic al gangli o ne cto� i nterfered with t he nutritional s t atus and growth h ormone secre t ion in rat s . Such e ffe cts c ould re duce
acce s s ory gland act ivity. Plas ma te s tosterone data obtaine d from rams
i n Experime nt
4
did not shol'l variat ions which c ould be us e d i nexplaining the differe nt leve ls of acc e s s ory s e x gland act iv ity c aus e d by the s urgical tre atme nts .
Reduce d HIOMr activity of pineal glanfu3 from rams whi c h had bee n cranial cervical ganglione ctomize d provide d a che ck o n t he e ffic ie ncy o f the s urgery , as we l l as confirming the assumpt ion that this
operation would alte r pineal function. Pineal cell nuclear de ns ity provided an i ndex of ce llular act ivity as it is reduced whe n pineal ce lls are active and have large cyt oplasmic v olume s , he nce lower
nuc le ar de ns it ies
(
Roth, Wurtman and Altsc hule ,1 962 ) .
The e ffect of ganglionecto� on pine al activ ity als o was indicated by the lowe r pine al we ights i n the ganglione c t omized rams , however the reduction i n we ights was not stat is t ically s ignificant . With the limitat ions in the hist ologic al staining technique available , it was not poss ible t o assess whe t her changes i n de ns ity o f pineal ax o ns occ urred as a re s ult of ganglionecto�.It seeiD3 re as onable to c onclude that s ince removal of the c ranial cervical ganglia reduc e d pineal activ i ty the n, in the ram as in the rat and golde n haiDBter, these ganglia are an i nte gral part of the affere nt nerve s upp� t o the pineal gland.
( 5 )
General D is cus s ionCranial cervical sympathe c t omy may have had e ffe cts on
structure s other than the pineal gland and the se must be c ons idere d . The cranial cervical ganglia are i nv olve d i n the sympathe t ic
1 72
aut o nomic control of blood ves s e ls in the head, inc luding thos e
supplying the pituitary gland and the re s t of t he brain. Removal of the se ganglia has bee n reported t o lead t o a fall in cerebral blood volume in mice
(
Edv i ns s on, Owman and We s t ,1 971 ).
Thus it may be poss ible t o ascribe all the e ndocr�ne c o�� e que nces of ganglione c t or�to alterat ions in rate of pituitary blood flow . C o ns e que ntly,
definit ive stateme nts about the role of the pineal gland in re gulati ng reproduction should be made only after obs erving the e ffe cts of
p ineale c t omy .
T he s ignificant res ults which could b e attribute d to olfac t ory bulbe c t o� did not provide much ins ight into the poss ible role of the olfactory system i n t he s e as onality of re product ion. D isruption of
the se as o nal change s of plasma LH, and to a lesser exte nt , of plasma tes tos terone leve ls s hown by the BulbX group, le nt s upport to t he poss ibility that olfaction could play a part in controlling the onset
of the breeding s e as on. Furthermore , as des truction of the o lfact ory
bulbs would have disrupte d ne rvous connections from t he vomeronas al organ
(
Alberta,1 974 ;
Powers and Winans �1 975 ) ,
it is not pos s ible t o dis c ount the idea that the alteration in s e as onal change s o f plasma LH and t e s tosterone s e cre tion re sulte d indire ctly from the loss of the v omeronasal c ompone nt of o lfact ion. However, the h ormone and seme n data was obtaine d from only thre e rams , s o aey conc lus ions must be treat e d with cauti on.Neverthe le s s this experime nt e s t ablished that e nv ironme ntal fact ors c ould influe nce the reproductive sys tems of rams via t he ir p i ne al glands and o lfactory sys tems . T he importance of olfactory
s t imuli in seas onal reproduc t ive change s c o uld not be as certain(�d, nor was it poss ible to as certain the me chanisms by which s uc h stimuli
c ould modi� reproduc tion. Howe ver on the othe r hand phot ope r iodic s t imuli, which are known to control annual pho t operiodic cyc le s i n d ome s tic animals
(
Ortavant , Maule on a nd Thibault , 1 964) , may exert the ir influe nce on reproduction i n rams by reduc i ng pineal ac t iv i ty during the summer months . This e ffe ct of dai � photoperiod probab� is manifeste d by the i ncre ase d se cre t io n of gonadotrophi ns at t his t ime of the year, as was seen for plasma LH le ve ls re c orde d in Experime nt3 .
A s imilar explanat ion may have acc ounted for t hec hange s in plasma prolactin leve ls i n unoperate d animals , s o it would have be e n informative to have me asure d FSH as we ll. Unfortunate ly, a s atisfac tory assay for this hormo ne was not available .
1 74
C HAPI'ER V
E FFECTS OF DI FFERE NI'