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