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Effects of gonadectomy and hypophysectomy on the pineal body in the mouseA quantitative morphological study.

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Effects of Gonadectomy and Hypophysectomy on the
Pineal Body in the Mouse: A Quantitative
Morphological Study
TAKASHI I T 0 AND SHOJI MATSUSHIMA
Department of Anatomy, Hokkaido University
School of Medicine, Sapporo, J a p a n
ABSTRACT
A quantitative morphological study was made to assess the effects of
gonadectomy and hypophysectomy on the pineal in the mouse. Gonadectomy caused
a slight increase in the pineal volume whereas hypophysectomy induced a marked decrease. The increase in pineal volume after gonadectomy was associated primarily
with slight enlargement of pineal cells in the peripheral area of the gland, and the
larger decrease in pineal volume after hypophysectomy correlated with marked atrophy
of pineal cells throughout the entire gland.
Most of the earlier morphological studies
on the pineal body have been of a qualitative rather than of a quantitative nature.
In our previous paper, the postnatal development of the mouse pineal was dealt with
quantitatively (It0 and Matsushima, '67).
The present investigation was undertaken
to assess quantitatively the effects of gonadectomy and hypophysectomy on the
mouse pineal by the same morphometric
method as used previously. No accurate
quantitative information is available for
the mouse as to whether the pineal undergoes any appreciable change following gonadectomy and hypophysectomy.
carded from the experiments. The control
group consisted of 20 normal males and
20 virgin females of 120 days of age.
The mice were killed with chloroform
after body weight was recorded. The skull
was then immediately opened and the
brain, including the pineal body, was dissected out and fixed in Bouin's fluid for
24 hours, dehydrated and embedded in
paraffin in the routine manner. The tissue
was sectioned in the plane in which the
pineal was sagittally oriented. The pineal
was serially sectioned at 6 w and stained
with hematoxylin and eosin. For both the
experimental and control groups the pineal
volume was measured by means of the
MATERIAL AND METHODS
same volumetric procedure in serial histoMice of Japanese dd-strain were used in logical sections as described in detail in
this investigation as in our previous one. our previous paper (Ito and Matsushima,
The animals were given standard commer- '67). An estimate of cell size of the pineal
cial mouse pellet diet and water ad libitum. was determined through the population
The mice were divided into three groups, density of the nuclei. The histometric
two experimental and one control (table 1). method used for determining the nuclear
One experimental group was gonadecto- density was also the same as described
mized at 35 days of age and killed at 120 previously. Analysis for significant differdays. This group contained 20 males and 15 ences between the control and experimenfemales. The second experimental group, tal groups was made using the Student's
consisting of 11 males and 14 females, t-test.
were hypophysectomized at 90 days and
RESULTS
killed at 120 days. Hypophysectomy was
( 1) Pined voZume.
The volumetric
carried out by the intra-aural aspiration
method. At autopsy completeness of hy- data of the pineal obtained in this study
pophysectomy was checked by careful ex- are presented in table 1 and figure 1. The
amination of the sella turcica, the adrenal average pineal volume of the gonadectoglands and the gonadal organs. All mice mized group was larger for both sexes than
with any residual hypophysis were dis- that of the control group. Particularly in
ANAT. &c.,
162: 479-482.
479
480
TAKASHI I T 0 AND SHOJI MATSUSHIMA
TABLE 1
Body weights and pineal volumes of control and experimental mice
Sex
~~$~~
Body weight
Pineal volume
Control
male
female
20
20
mean 2 S D mms, mean S D
28.6 k 2.8
0.076 2 0.014
23.9 2.4
0.074 0.011
Gonadectomized
male
female
20
15
27.5 f2.3
Hypophysectomized
gtzle
11
14
27.1 2 5.5
g.
1
*
*
29.0f 3.0
0.086 & 0.019
0.089 & 0.019
25.9
* 5.2
0.047? 0.008
0.048 rfr 0.008
simificanca
Statistical
0.05
< P < 0.07
P < 0.01
P < 0.001
P
< 0.001
Compared to controls of the same sex using the Student's t-test.
I
Control
I Gonadectomized I
Hypophysectomized
-+P
Fig. 1 Pineal volumes of control and experimental groups. Open circle indicates pineal
volume of each male and solid circle, pineal volume of each female. Bars represent mean
and standard deviations in each group of each sex. M, male; F, female.
the female the difference between gonadectomized and control groups was statistically significant ( P < 0.01). In the male,
however, the difference was not significant
(0.05 < P < 0.07). The pineal volume of
hypophysectomized mice was strikingly
smaller than that of controls. The difference between both groups was highly significant for both sexes (P < 0.001).
( 2 ) Population density of pineal and
stromal cell nuclei. Table 2 and figure 2
show the nuclear density of the pineal
(parenchymal) and stromal cells for each
group by sex. As seen in this figure, the
population density of stromal cells is extremely low as compared with that of pineal cells. This indicates that the pineal
cells are the major cellular constituents
and the stromal cells, only minor ones. As
described in a previous paper (It0 and
Matsushima, '67), the elements other than
pineal cells were included among the stroma1 cells. In normal controls, the density
of pineal cells was almost the same in both
the central and peripheral areas of the
gland for each sex. In gonadectomized
481
PINEAL AFTER GONADECTOMY AND HYPOPHYSECTOMY
TABLE 2
Population density o f pineal and stromal cell nuclei (number o f nuclei per unit area)
Sex
Pineal cell
Stromal cell
Peripheral
Central
Peripheral
Central
mean 5 S D
mean kSD
mean k S D
mean k S D
Control
male
female
5 1 . 0 f 7.7
50.5& 5.0
51.9f10.4
52.9-C 7.7
11.122.6
9.5C3.9
7.9f2.7
7.7-2.4
Gonadectomized
male
female
4 4 . 2 2 7.2
44.3-C 6.5
53.1k 7.2
5 3 . l C 6.5
8.6C1.7
8.122.4
7.4C1.6
8.0k1.7
Hypophysectomized
male
female
106.2218.5 114.6f18.1
97.4214.4 101.8212.3
13.7k2.7 12.3e2.2
13.023.2 11.6k2.9
~~
G onadectomired
.
I
E
E
Hypophy sectomired
In
:
0
Stromal Cell
Y
g 100
h
.-t
t
3
t
a
._
50
a
-0
3
z
-t
0
L
al
a
E,
z
M
F
entral
M
F
!ripheral
Fig. 2 Nuclear density in control and experimental groups. Each column represents mean value
and vertical line, standard deviation. Central, central area of the pineal; peripheral, peripheral area
of the pineal. M, male; F, female.
mice, the density in the central area remained unchanged, while that in the peripheral area was slightly reduced. In
hypophysectomized mice, the pineal cells
in both the central and peripheral areas
showed a marked increase in the nuclear
density. The population density of stromal
cells was similar in control and gonadectomized groups. In the hypophysectomized
group a slight increase was found, which
was considered due to marked atrophy of
the pineal.
A comparison of figures 1 and 2 suggests
that the volumetric change after gonadectomy and hypophysectomy is associated
primarily with the population density of
pineal cell nuclei, viz. the pineal cell size.
A slight increase in pineal volume after
gonadectomy is attributed to slight enlargement of pineal cells in the peripheral area,
and a marked decrease in pineal volume
after hypophysectomy is a consequence of
a remarkable decrease in the pineal cell
size throughout the entire gland.
DISCUSSION
The functional significance of the pineal
is not yet clarified entirely, but its relation
to the gonads has been suggested by various lines of evidence (for reviews, see Kitay
and Altschule, '54; Kappers and Schadk,
'65; Kitay, '67). The relation of the pineal
to light stimulation, which has recently
been reported, is suggested on the basis of
the pineal-gonadal relationship (Kitay, '67;
Hoffman and Reiter, '65; Thihblot, '65).
482
TAKASHI IT0 AND SHOJI MATSUSHIMA
Nevertheless, there have been relatively
few basic data about the pineal-gonadal
relationship. Effects of gonadectomy on
the pineal structure have been reported by
a number of investigators, but the early reports have been conflicting as to whether
the pineal is affected by gonadectomy:
some failed to find alteration, others found
atrophy, and still others claimed hypertrophy, in the pineal after gonadectomy. The
confusion seems to be due, in part at least,
to a lack of precise quantitative analyses
(for references, see Kitay and Altschule,
'54; Kitay, '67). Effects of gonadectomy on
pineal size were quantitatively dealt with
by Fiske, Pound and Putnam ('621, who
reported the slightly increased weight of
the pineal in gonadectomized rats. The
present volumetric data also indicate that
the gland tends to increase, though not
always significantly, in volume after gonadec tomy.
There has also been little exact information available in the literature concerning
the effects of hypophysectomy on the pineal. Quantitative data on this subject were
provided by Reiss, Mauer and Sideman
('63). These investigators found that the
pineal did not atrophy in hypophysectomized young rats, because its relative
weight adjusted to body weight did not
change. Our data, on the contrary, demonstrate that hypophysectomy in adult mice
actually induced a marked decrease in
pineal volume and that the decrease was
highly significant even on a body weight
basis.
In any case, the above results, suggesting the possible relation of the pineal to
the gonads and to the hypophysis, favor
the idea that the pineal exerts an inhibitory action on gonadal function through
the hypophysis, although no definite conclusions can be drawn with relation to
pineal function. Concerning qualitative
changes of the pineal after gonadectomy
and hypophysectomy, increase in lipid content of the rat pineal was histochemically
observed in ovariectomized rats (Zweens,
'63, ' 6 5 ) and decrease in hypophysectomized rats (Hungerford and Panagiotis,
'62). Such changes appear to be related to
those in the size of pineal cells. Cytologic
changes of the pineal of gonadectomized
and hypophysectomized mice will further
be examined by light and electron microsCOPY.
LITERATURE CITED
Fiske, V. M., J. Pound and J. Putnam 1962 Effect of light on the weight of the pineal organ
in hypophysectomized, gonadectomized, adrenalectomized or thiouracil-fed rats. Endocrinology, 71: 130-133.
Hoffman, R. A., and R. J. Reiter 1965 Pineal
gland: Influence on gonads of male hamsters.
Science, 148: 1609-1611.
Hungerford, G. F., and N. M. Panagiotis 1962
Response of pineal lipid to hormone imbalances. Endocrinology, 71: 93f3-942.
Ito, T., and S. Matsushima 1967 A quantitative morphological study of the postnatal development of the pineal body of the mouse. Anat.
Rec., 159: 447452.
Kappers, J. A., and J. P. Schad6 1965 Structure
and function of the epiphysis cerebri. In: Progress in Brain Research, Vol. 10, Elsevier, Amsterdam-London-New York.
Kitay, J. I. 1967 Possible functions of the pineal gland. In: Neuroendocrinology, Vol. 2, Academic Press, New York-London, pp. 641-664.
Kitay, J. I., and M. D. Altschule 1954 The pineal gland. Harvard Univ. Press, Cambridge,
Mass.
Reiss, M., I. Mauer, M. B. Sideman, R. H. Davis
and E. S. Plichta 1963 Pituitary-pineal-brain
interrelationships. J. Neurochem., 10: 851-857.
Thikblot, L. 1965 Physiology of the pineal body.
In: Progress in Brain Research, Vol. 10, Elsevier, Amsterdam-London-New York, pp. 479488.
Zweens, J. 1963 Influence of the oestrous cycle
and ovariectomy on the phospholipid content
of the pineal gland in the rat. Nature, 197:
1114-1115.
1965 Alterations of the pineal lipid
content in the rat under hormonal influences.
In: Progress in Brain Research, Vol. 10, Elsevier, Amsterdam-London-New York, pp. 540551.
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effect, stud, pineal, mouse, body, hypophysectomy, gonadectomy, morphological, quantitative
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