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KMID : 0378019690120070065
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New Medical Journal
1969 Volume.12 No. 7 p.65 ~ p.78
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Autoradiographic Studies on the Effect of Sexual Hormones on the Periodontium of Rat Using H³-thymidine
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Abstract
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Effect of sexual hormones on the renewal rate of cells in the periodontium of young adult rat of both sexes, weighing about 150 grams each, were studied by autoradiographic technique using H3thymidine.
15 male rats were evenly divided into three groups; a normal control group, another group which was castrated and the third group administered with testosterone propionate after castration. 20 female rats were also evenly divided into four groups; one group in diestrous, another group in estrous, the third group which was ovariectomized and the fourth group administered with estradiol benzoate after ovariectomy.
The sexual hormones were injected subcutaneously into castrated or ovariectomized rats twice at an interval of over 24 hours with a dose of 2 micro gm. /gm. body weight. 24 hours after the hormone injection, the animals were given intraperitonealy a dose of 0. 8 micro c. /grn- body weight of tritiated thymidine which was specifically incorporated into DNA and were sacrificed 24 hours thereafter. Pieces of the periodontium were fixed in neutral buffer solution and decalcified in the 10 percente solution of EDTA for 4 weeks. The pieces were made into celloidin of 10 microns.
Percentage from labelled nuclei per 1, 000 nuclei in the periodontium were calculated and the ratio was set as the radioactive index.
The obtained -results were as follows;
1. The renewal rate of the periodontal cells was highest in the epithelial layer, and lowered on the sequence of epithelial layer, peridontal membrane, lamina propria and alveolar bone. 2. The radioactive indices of the neriodontium of the castrated rats, 1. 37, were markedly reduced
compared with those of the normal control group, 2.83, and the indices were restored to the normal level, -3.22, after testosterone propionate injection.
3. During diestrous period, the radioactive indices of the periodontium in the female . rat, 2.56, were generally larger than those in the estrous period, 1.45.
4 The radioactive indices of the periodontium of the ovariectomized female rats, 1. 13, were markedly reduced compared with those of the diestrous group and lowered to or a little lower level than those of the estrous group and the indices were restored to or a little higher level than those of the diestrous group after hormone injection.
5. Consequently, it is to be believed that the sexual hormones increase also the renewal rate of the periodontal cells and the injected sexual hormones also accelerate the value of DNA synthesis in the periodontal cells of the castrated or ovariectomized rats, finally the normal or a little higher is reached.
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KEYWORD
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