Biological, Immunological and Physical Investigations on Human Chorionic Gonadotropin

Merz, Wolfgang E.; Hilgenfeldt, Ulrich; Dörner, M; Brossmer, Reinhard

doi:10.1515/bchm2.1974.355.2.1035

Cited by 37 publications

(17 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Van Hall et al (1972) showed that progressive desialylation of hCG led to a reduced half-life of the hormone in plasma. There was indeed a correlation between the in vivo bioactivity and the sialic acid content of several isoelectric hCG components (Merz et al, 1974, Nwokoro et al, 1981, suggesting that sialic acid is responsible for the electrical heterogeneity in highly purified hCG. In addition, deglycosylation of hCG by anhydrous hydrogen fluoride caused a decrease in its cyclic AMP accumulation activity in vitro in rat interstitial cells, though the ability of the deglycosylated hCG to bind receptor was retained or increased (Manjunath and Sairam, 1982).…”

Section: Discussionmentioning

confidence: 93%

Different profiles of isoelectric avian luteinizing hormone components in biological activity and immunoreactivity.

Hattori

Wakabayashi

1983

Endocrinol Japon

View full text Add to dashboard Cite

Chicken LH components from the glycoprotein fraction of the anterior pituitary glands have been separated to isoelectric homogeneity by means of isoelectric focusing, and investigated for their biological activities in vitro. The activities of these components were measured with LH receptor binding, cyclic AMP accumulation and testosterone production in rat Leydig cells at equal doses expressed as immunoreactivity of IRC-2 (Gunma).All the components were active in the heterologous assay systems, although the relative potency expressed as the ratios of biological activity to immunoreactivity (B: I) differed significantly among the components. Component I, the amount of which is the largest (40-50%), with the most alkaline isoelectricpoint (pI) showed the highest B: I ratio, and the B: I ratio decreased with decreasing pI in the same way as in rat LH components (Wakabayashi, 1980;Hattori et al., 1983). Therefore, pituitary LH from photostimulated male quail, where the relative amount of component I was increased, was estimated to have higher B: I ratios than that from short-day (SD) treated male quail. Furthermore, the differences in activities among the components obtained by the three assays were in the following order: testosterone production>cyclic AMP accumulation>receptor binding, suggesting that the hormonal actions of components with higher B: I ratios (I, II and III) are efficiently amplified in the biological response to the final step. In the incubation of pituitary glands with hypothalamic extracts, component I in the pituitary glands from the long-day (LD) treated group was mostly decreased after the incubation, while all the components were decreased in parallel in the SD-treated group. The results suggest that the LH component releasable to GnRH changes in endocrine status though component I with the highest B: I ratio is relatively releasable in both SD-and LDtreated groups.Pituitary glycoprotein hormones consist of a mixture of several isoelectric components in animal species and man (Braselton and

show abstract

Section: Discussionmentioning

confidence: 93%

Different profiles of isoelectric avian luteinizing hormone components in biological activity and immunoreactivity.

Hattori

Wakabayashi

1983

Endocrinol Japon

View full text Add to dashboard Cite

show abstract

“…The carbohydrate residues play an important role in prolonging plasma survival and preserving biological activity of hCG [13,29]. Further, variations in the carbohydrate moiety particularly the sialic acid content, are responsible for the microheterogeneity of hCG, which may best be visualized by isoelectric focusing [12,25,28]. The structure of hCG including the carbohydrate moiety has in turn been shown to be closely related to its function [9,30,37].…”

Section: Discussionmentioning

confidence: 99%

“…Urinary extracts contain, in addition to the intact hCG molecule, a variety of hCGrelated peptides or fragments of hCG including sialic acid deficient hCG variants, free hCG- [3, hCG-J3 core fragment and 0~-subunit [5,11,14,19,36]. Further, with respect to the intact hormone, hCG, as other glycoprotein hormones, is composed of a mixture of several isoforms that differ in their sialic acid content and as a result display different isoelectric points on isoelectric focusing [12,25,28].…”

Section: Discussionmentioning

confidence: 99%

Molecular heterogeneity of human chorionic gonadotropin in serum and urine from patients with trophoblastic tumors

et al. 1993

View full text Add to dashboard Cite

Many studies on the structure and function of human chorionic gonadotropin (hCG) have relied on purified hCG preparations obtained from pregnancy urine. In the present studies, in order to demonstrate possible differences between the hCG species present in serum and those released into urine, we examined serum and urinary samples derived from patients with trophoblastic tumors and of pregnancy origin by sodium dodecyl sulfate electrophoresis, isoelectric focusing, and two-dimensional electrophoresis including immunostaining with a specific hCG antibody and densitometry of the protein bands. This type of analysis was presently feasible only in patients presenting with extremely high serum levels of hCG and was therefore limited to seven patients with testicular cancers, one woman with a hydatidiform mole, and one pregnancy sample. We found marked differences in the isoelectric focusing pattern between urinary and serum hCG samples, with the urinary hCG consisting of more alkaline pI variants than that present in the serum of the same patients. Tumor hCG differed from pregnancy hCG in that it contained more acidic variants, and this was true for urinary and serum-derived materials. In some tumor and pregnancy samples an hCG immunoreactive material of lower molecular weight than hCG itself was found. In conclusion, the present studies, extending previous findings on the microheterogeneity of hCG, indicate that serum and urinary-derived hCG may differ in the composition of the isoform spectrum, as does tumor and pregnancy hCG. Further, in some patients hCG immunoreactive molecules exist that differ markedly from hCG in size and charge. These observations suggest that, whenever possible, serum-derived hCG materials should be used to define the molecular structure of hCG and assess its biological activities.

show abstract

“…Purification of crude hCG (Schering AG, Berlin, FRG) was performed according to the method of Canfield et al (1971) with slight modifications as described by Merz et al (1974). The purification procedure consists of four steps: batch adsorption of the crude hormone on SP Sephadex C 50 (in the following, the non-adsorbed material of this step is designated fraction I); chromatography on DEAE-Scphadcx A 50. and chromatography on Sephadex G 150.…”

Section: Human Chorionic Gonadotropinmentioning

confidence: 99%

“…This procedure is described elsewhere (Merz et al, 1979). Biological activity of hCG was determined by means of the rat prostate assay (Merz et al, 1974). The Second International Standard for Choriogonadotropin served as reference.…”

Section: Human Chorionic Gonadotropinmentioning

confidence: 99%

Effects of Crude and Purified Human Chorionic Gonadotropin on Lymphocyte Response

Schmidt¹,

Merz²,

Lenhard³

et al. 1981

Gynecol Obstet Invest

View full text Add to dashboard Cite

Human chorionic gonadotropin (hCG) preparations with different biological activities were tested for their inhibitory effects on mitogenic of allogenic induced lymphocyte response. Various crude hormone batches inhibited the lymphocyte reaction in a dose-dependent manner. However, we found a varying suppression of lymphocyte response not correlated to the biological activity (2,660–4,300 IU/mg) of crude hormone. Fractions with very low gonadotropic activity ( < < 500 IU/mg) showed a 100-fold inhibition of lymphocyte reaction. Conversely, the enrichment of highly purified hCG with strong biological activity ( > 10,000 IU/mg) had no inhibitory effect on mitogenic or allogenic induced lymphocyte transformation. I soelectro focussing and immunoelectrophoretic investigations indicated that the inhibition is probably caused by nondialyzable sialoglyco-proteins. It is therefore very doubtful whether hCG plays an important part in maternal tolerance of the fetal allograft.

show abstract

Biological, Immunological and Physical Investigations on Human Chorionic Gonadotropin

Cited by 37 publications

References 1 publication

Different profiles of isoelectric avian luteinizing hormone components in biological activity and immunoreactivity.

Different profiles of isoelectric avian luteinizing hormone components in biological activity and immunoreactivity.

Molecular heterogeneity of human chorionic gonadotropin in serum and urine from patients with trophoblastic tumors

Effects of Crude and Purified Human Chorionic Gonadotropin on Lymphocyte Response

Contact Info

Product

Resources

About