Abstract
In our previous report it was suggested that urinary hCG is composed of two components. One is dominant in LH-like activity and the other is dominant in FSH-like activity, and the ratio of these components differs according to the stage of pregnancy.
In order to clarify the nature of plancental hCG, this study has been performed.
The crude hCG fractions extracted from trophoblastic tissue of normal placenta and hydatidiform mole by the percolation method of Bates were purified by the combination of Sephadex gel filtration, CM-C and DEAE-C chromatography. Two purified hCGs (hCG-A and hCG-B) were obtained.
Biological activities of components were measured by an ovarian weight method in immature female rats (λ = 0.176), using the Second International Standard hCG as a reference standard preparation.
Examined by polyacrylamide disc gel electrophoresis, hCG-A and hCG-B showed single bands.
Specific biological activities of hCG-A and hCG-B from normal tissue were both 8,200 IU, but those of hydatidiform mole were very high, namely, hCG-A had an activity of 23,000 IU and hCG-B 8,600 IU.
Moreover, the hCGs isolated from molar tissue contained much higher hexose, but much less hexosamine, than hCGs from normal trophoblastic tissue. hCG-A, which contained more hexose, had less sialic acid than hCG-B.
In Ouchterlony immunodiffusion, hCG-A and hCG-B made precipitation lines respectively with anti-hCG-A serum and anti-hCG-B serum, and in immunoelectrophoresis in agar hCG-A and hCG-B formed single precipitation lines with corresponding antiserum.
In addition, hCG-A was neutralized biologically only by anti-hCG-A serum, and the same was observed concerning the hCG-B and its and serum system, using an ovarian weight method above mentioned.
Then 200 IU of hCG-A or hCG-B was injected into the hypophysectomized immature female rats and the biological properties of two hCGs were examined.
As a result, hCG-A promoted the normalization and hypertrophy of the interstitial cells and did not stimulate any follicular development, but hCG-B stimulated the follicular growth only.
At the same time, although hCG-A had a remarkable action to induce the ovarian Δ5-3β-ol dehydrogenase activity in the follicular walls and in the interstitial cell mass, hCG-B could not activate the enzyme activity.
In the other experiment, after the injection of hCG-B into the hypophysectomized immature rats, the marked increase of 3H-thymidine uptake of granulosa cells of the growing follicles was recognized, but with hCG-A the uptake was not so clear.
On the other hand, hCG-A promoted the ovarian phosphorylase activity and elevated the serum progesterone level of the hypophysectomized rats.
From the above experimental results, it was concluded that placental hCG is composed of two components : hCG-A (human chorionic luteinizing hormone : hCLH) with stimulating effect of interstitial cell normalization and its hypertrophy and with promoting effect of ovarian steroidogenesis, and hCG-B (human chorionic follicle stimulating hormone : hCFSH) with follicle stimulating effect only. They are different from each other not only biologically but also immunologically and chemically.
In an attempt to determine the mechanism of production and secretion of these two hCGs in the chorionic tissue and to investigate their hormonogenesis in placenta, we decided to cultivate the chorionic tissue in vitro and to make the biosynthetic labeled hCGs. As the first step of this work, the possibility of organ culture of chorionic tissue was examined in the synthetic medium “199” without serum.
The results of this study are as follow :
1) During cultivations of the chorionic tissue, hCG concentration in the media increased remarkably, estimated not only by bioassay with the ovarian weight method in immature rats,
