牛における抗胎盤性性腺刺戟ホルモン(Anti-HCG)に関する研究

第IV報 Anti-HCGの再産生について

抄録

In earlier reports of our series of studies, it was demonstrated that the antihormone against HCG (Anti-HCG) might be produced easily in cattle. In this paper we undertook investigations on the reformation of Anti-HCG in cattle by injecting smaller doses of HCG than those used in the previous experiments.
A female calf and a cow with normal estrous cycle and 3 cows with cystic ovaries were used in the experiments. These animals had been received one or more injections of various doses of HCG and their serum Anti-HCG had been determined to be positive approximately 150-200 days prior to the present experiments. The methods to determine the serum Anti-HCG were same as described in previous reports.
The results obtained were as follows.
1. Reformation of Anti-HCG in experimental animals.
A female calf and a cow employed in the present experiments were same as described in report I. After the determinations of serum Anti-HCG produced formerly became negative, the 2 animals were reinjected intravenously with daily dose of 2, 500 MU of HCG for consecutive 4 days (10, 000 MU in total). This mode of experiment was repeated 3 times at intervals of 100 days and 105 days respectively. The results of the determinations of serum Anti-HCG were shown in Table 1 (Cattle No. 1) and Table 2 (Cattle No. 2). The results obtained from the experiments indicated that the Anti-HCG was reformed by reinjecting HCG more readily than that was produced by injecting HCG for the first time. The potencies of the reformed Anti-HCG (HCG inhibiting ability per 1 cc. of serum) about 10 days after the reinjections in these 3 trials were 3.0 MU, 6.0 MU and 12.0 MU in cattle No. 1 and 1.5-3.0 MU, 3.0 MU and 6.0 MU in cattle No.2 respectively. After the 3rd reinjection, the reformed Anti-HCG remained until 100 days in cattle No. 1 and 75 days in cattle No.2, and then disappeared on the 125th day and 100th day respectively. It was observed from these data that the potency of the reformed Anti-HCG increased gradually through the repeated experiments, and the duration of existence of Anti-HCG was longer in the animal having higher Anti-HCG potency than that having lower potency.
In the next experiment, 105 days after the 3rd reinjection, cattle No. 2 was received single injection of 2, 500 MU of HCG in order to examine whether such smaller dose of HCG might induce the reformation of Anti-HCG. Detectable amounts of Anti-HCG appeared on the 3rd day (HCG inhibiting titer per cc. of serum : 1.5 MU) and the reformed Anti-HCG was observed to increase rapidly from the 5th to the 10th day (inhibiting titer: 6.0-12.0 MU/cc.) as shown in Table 3. From these results, it appeared that the reformation of Anti-HCG could be induced rapidly, reached to the maximum level about 10 days after the reinjection, and thereafter fell gradually.
2. Reformation of Anti-HCG in cows with cystic ovaries.
Three cows with cystic ovaries were also employed in the experiments of the reformation of Anti-HCG. They had been received 2-3 intramuscular injections of HCG for treating ovarian follicle cysts. The histories of the HCG treatments and the results of the Anti-HCG determinations in these animals were as shown in Table 4. The initial potency of the serum Anti-HCG (serum No. I) was 24.0 MU or more, 3.0 MU and 3.0 MU respectively in these 3 animals. All of them had recovered from ovarian follicle cysts by intramuscular (Cattle No. 2) or intrafolliclar (Cattle No. 1 and No. 3) injections of HCG, and become pregnant. The reinjections of HCG were held at the time when 2 (Cattle No. 2 and No. 3) of the 3 animals were in about 170 days of pregnancy and the determinations of serum Anti-HCG (serum No. II) being negative, while remaining 1 animal (Cattle No. 1) suffered again from ovarian follicle cyst about 60 days abortion happend on the 89th day of pregnancy and the determination of serum Anti-HCG (serum No. II) remaining positive (inhibiting titer: 1.5 MU/cc.).