Immunologic and physical characterization of human chorionic gonadotropin (hCG) secreted by tumors

Development of the home pregnancy test

The home pregnancy test works by measuring human chorionic gonadotropin (hCG) hormone in urine. This hormone was initially studied in NICHD intramural laboratories as a reliable marker of certain tumors. Refinement of the assay for hCG detection to enhance specificity enabled its ready application to pregnancy detection.

Disulfide bond formation is not required for human chorionic gonadotropin subunit association. Studies with dithiothreitol in JEG-3 cells

To study the influence of disulfide bridge formation on the assembly of the subunits of human chorionic gonadotropin in JEG-3 choriocarcinoma cells, dithiothreitol (DTT) was used to create a reducing milieu in the endoplasmic reticulum (ER) in vivo. In the presence of 5 mM DTT during pulse-chase experiments all of the beta-subunit precursors observed in unperturbed cells (pbeta(0), pbeta(1), pbeta(2), and beta(*)) collapsed into the pbeta(0) form. The reducing milieu of the ER was reoxidized in less than 5 min after removal of DTT from the medium. DTT markedly increased the half-life of the pbeta(0) precursor from 8.8 to 65.2 min. Under reoxidation conditions, the beta-subunit precursors folded back from pbeta(0) in less than 5 min. In unperturbed JEG-3 cells, the alpha-subunit was present in both fully glycosylated and monoglycosylated precursor (pre-alpha) forms. The attachment of the second N-linked glycan residue of the alpha-subunit was accelerated in the presence of DTT, and consequently pre-alpha-subunit was missing from the DTT-treated cultures. The formation of alphabeta-dimers appeared to be at least partially independent of the oxidation state in the ER. The alphabeta-dimer was present under conditions in which disulfide bridge formation was prevented by exposure to 5 mM DTT before and during the pulse period. This clearly suggests that the human chorionic gonadotropin subunits may acquire association-competent conformations even when no disulfide bridge formation has taken place.

Pathophysiological importance of various molecular forms of human choriogonadotropin

Human chorionic gonadotropin (hCG), its subunits and fragments are widely used for diagnostic purposes. In addition to the diagnosis of pregnancy and pregnancy related disorders, hCG determinations are used for diagnosis of trophoblastic and recently also nontrophoblastic tumors. The use for diagnosis of nontrophoblastic tumors requires highly specific and ultrasensitive assays. With these, it is possible to measure the concentrations of both hCG, the free beta-subunits and the so called beta-core fragment in healthy subjects. Therefore it is important to establish reference values for these and also to be aware of the influence of physiological factors on the serum and urine concentrations. Improved standardization of the assay methods is also essential for these novel applications of hCG determinations to become useful.

Assessment of urinary gonadotropin in solid carcinomas other than gynecological tumors

To the already long list of existing tumor markers, a new marker has been recently added, the urinary gonadotropin peptide (UGP). This marker is determined in the urine of cancer patients and is considered to be particularly specific for ovarian carcinomas. The purpose of our study was to assess the specificity of UGP in a variety of malignancies other than ovarian carcinomas, e.g., breast, colonic, lung, and urogenital tumors (n = 50 each). The tumors were compared with benign lesions of the same organs. Urine samples of 50 healthy donors served as controls. The 450 urine samples were tested in duplicate using the UGP EIA-kit from Ciba Corning Diagnostics. All tumors were staged and histologically classified. For normalization in all samples, creatinine levels were determined. UGP was found in all tested tumors, however, with very low sensitivity of 20% in urogenital tumors, 46% in lung, and 30% or 27% in colon and breast carcinomas, respectively. The specificity of UGP was comprised between 100% (breast) and 88%. Clearly elevated UGP-concentrations were seen in postmenopausal women. A comparison of UGP with the optimal markers for each tumor system showed that UGP is not superior to these markers. However, we can confirm UGP as being an optimal marker for gynecological carcinomas.

Maternal urinary beta-core fragment of hCG/creatinine ratios and fetal chromosomal abnormalities in the second trimester of pregnancy

Our aim was to evaluate the potential value of the ratio of the maternal urinary beta-core fragment of human chorionic gonadotropin (beta C-hCG) to creatinine (Cr) in discriminating between normal pregnancies and pregnancies associated with fetal chromosomal abnormalities. We hypothesized that pregnancies with fetal chromosomal abnormalities had abnormal quantities of beta C-hCG in the urine. The aims of the present study were to investigate retrospectively whether maternal urinary ratios of beta C-hCG/Cr are abnormal in women carrying fetuses with chromosome aberrations and to determine normative median values and a reference range for beta C-hCG/Cr between 14 and 19 weeks' gestation. Maternal urinary beta C-hCG and Cr concentrations were measured in 150 healthy women from 14 to 19 weeks and compared with ten cases of fetal chromosomal abnormalities matched for gestational age. The preliminary cut-off points corresponded to 0.29 multiple of the normal median (MOM) and 2.83 MOM, which were equivalent to the tenth and 90th centiles of the normal range. Of ten cases of fetal chromosomal abnormalities, one out of one (100 per cent) case with trisomy 18 and three of four (75 per cent) cases of variant 9 chromosomes had low beta C-hCG/Cr (< or = 0.29 MOM). One of five (20 per cent) cases with Down syndrome had elevated beta C-hCG/Cr (> or = 2.83 MOM). Urinary beta C-hCG/Cr ratios obtained in the second trimester may be useful for improved detection efficiency of Down syndrome, trisomy 18, and inversion of chromosome 9. Second-trimester maternal urinary beta C-hCG/Cr should be investigated further as a potential marker for fetal chromosome anomalies.

Detection of a small molecular species of human chorionic gonadotropin in the urine of patients with carcinoma of the cervix and cervical intraepithelial neoplasia: comparison with other assays for human chorionic gonadotropin and its fragments

A low-molecular-weight glycoprotein containing sequences of the beta subunit of human chorionic gonadotropin (hCG) has been found in the urine of patients with carcinoma of the cervix using an immunoradiometric assay. This fragment has chromatographic and immunological identity with hCG beta core. This molecule was present in 52 to 77% of all patients with invasive disease, while between 11 and 27% of patients with cervical intraepithelial neoplasia (CIN) also exhibited significant hCG beta-core immunoactivity. Few patients had either a positive assay for intact hCG or a positive assay directed at an epitope on the beta subunit (beta-hCG radioimmunoassay) in serum. However, between 17 and 40% of patients with invasive disease were positive for free beta-subunit immunoactivity in the blood. The origin of the beta-core immunoactivity in the urine is uncertain; while tumor production cannot be excluded, it is possible that the molecule originates from renal metabolism of small quantities of the beta subunit of hCG. Regardless of the source of the molecule, hCG beta core is a far more sensitive marker of hCG production by tumors than is serum hCG.

Human chorionic gonadotropin, follicle-stimulating hormone, and luteinizing hormone in patients with epithelial ovarian carcinoma

Plasma levels of human chorionic gonadotropin (hCG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were studied in patients with epithelial ovarian carcinoma prior to and during chemotherapy. Blood samples were drawn for radioimmunoassay at monthly intervals. Plasma concentrations were compared to those of three different control groups: healthy post-menopausal women (PM), fertile women in the follicular phase of the menstrual cycle (FPh), and postmenopausal women with nongynecologic disseminated malignant disease (DMD). The hCG level was elevated in women with great tumor burden, such as large tumor volume, FIGO stage IV, and histologic type V. LH and FSH levels showed the reverse pattern. hCG concentration decreased during chemotherapy, whereas LH increased. Initial plasma concentrations were not found to have prognostic importance. We discuss the possibility that hCG is produced by the tumor, which stimulates steroid hormone production by the stroma, which, in turn, exerts negative feedback on FSH production by the pituitary.

Immunoreactive human chorionic gonadotrophin from the cyst fluid and CSF of patients with craniopharyngioma

A specific radioimmunoassay for the beta-chain of human chorionic gonadotrophin irHCG beta has demonstrated HCG-like material to be present in craniopharyngioma cyst fluid in nine consecutive patients with craniopharyngioma. There was no detectable LH/HCG bioactivity as assessed using testosterone production from isolated Leydig cells from rat testis in seven samples tested. One patient was also found to have measurable irHCG beta in the cerebrospinal fluid (CSF), which fell to undetectable levels following surgery; in this patient, there was clinical evidence that the cyst fluid had leaked into the CSF pre-operatively. Immunocytochemical staining for HCG beta and intact HCG was positive in five of the tumours. irHCG beta was not measurable in the serum of any of the patients.

Measuring human chorionic gonadotropin for detection of early pregnancy loss

Elucidation of the primary molecular structure of hCG, coupled with monoclonal antibody technology, has permitted the construction of a partial map of hCG surfaces. Based on this information, two-site immunoradiometric assays have been developed which permit the measurement of intact hCG and its subunit molecular forms with unprecedented sensitivity and specificity. These assays have been employed in a determination of the incidence of early pregnancy loss in a normal population with the finding that 22% of all conceptions producing measurable hCG terminate before becoming clinically evident.

Development and characterization of a monoclonal antibody to human embryonal carcinoma

A monoclonal anti-testicular carcinoma antibody was obtained via the somatic cell fusion technique by immunization of BALB/c mice with freshly prepared single cell suspension from a patient with testicular embryonal carcinoma with choriocarcinoma components. The hybridoma supernates were screened against the testicular carcinoma cells used in the immunization as well as normal mononuclear white blood cells isolated from the same patient. An antibody (5F9) was selected which bound to fresh tumor cells from two patients with embryonal testicular carcinoma and failed to bind to fresh tumor cells from 24 patients (2 seminoma, 2 melanoma, 3 neck, 2 esophageal, 1 ovarian, 3 colon, 1 prostate, 2 breast, 1 liposarcoma, 3 endometrial, 1 kidney, 1 adrenal, 1 larynx and 1 bladder tumors) or cell suspensions prepared from normal liver, lung, spleen, ovary, testes, kidney, red blood cells or white blood cells. The antibody was tested for its binding to several well established cancer cell lines, and was found to bind to the BeWo human choriocarcinoma and two human embryonal carcinoma cell lines. The antibody did not react with 22 other cell lines or with hCG. The antibody was labeled with 131I and injected into nude mice bearing BeWo tumors and evaluated for tumor localization by performing whole body scans with a gamma camera 5 days later. Six mice injected with the antibody showed positive tumor localization without the need for background subtraction while six mice injected with MOPC-21, a murine myeloma immunoglobulin, demonstrated much less tumor localization. Tissue distribution studies performed after scanning showed specific tumor localization (8:1 tumor: muscle) for the monoclonal antibody and no specific localization for MOPC-21. This antibody thus has selective reactivity with the surface of tumor cells from embryonal carcinoma (testicle) and choriocarcinoma both in vitro and in vivo.

Human chorionic gonadotropin in normal, inflammatory, and carcinomatous gastric tissue

Tissues from 12 patients with gastric ulcers, 50 patients with gastric carcinoma, and 2 normal subjects who died suddenly were examined immunohistochemically with antiserum against the beta-subunit of human chorionic gonadotropin. Human chorionic gonadotropin-beta-immunoreactive cells were present in the neck portion of the pyloric and pseudopyloric glands of normal and inflammatory gastric tissue. Gastric cancers located in the antrum-pylorus and the cardia were frequently associated with human chorionic gonadotropin immunoreactivity. These findings indicate that human chorionic gonadotropin-producing cells normally exist in the gastric mucosa, especially in the pylorus. It is speculated that normal human chorionic gonadotropin-producing cells may give rise to cancer in certain cases.

Paraneoplasic precocious puberty. Report of a new case with hepatoblastoma and review of the literature

A new case of precocious puberty secondary to production of human chorionic gonadotropin (HCG) by an hepatoblastoma was studied in an 8-month-old infant. A review was made of the 35 cases of paraneoplasic precocious puberty previously reported in the literature. The most frequent cause is hepatoblastoma, which was responsible for 18 cases. There are nine reports of mediastinal teratoma, six of which were observed in patients with Klinefelter Syndrome. In another six cases, the paraneoplasic syndrome was attributed to intracranial tumoration, and two of these patients showed teratoma with areas of choriocarcinoma, whereas germinoma was suspected for clinical reasons in another three. Lastly, one case of presacral teratoma and one of retroperitoneal carcinoma were reported. The differential characteristics of paraneoplasic precocious puberty are: almost exclusive occurrence in males, because of tumoral production of HCG, moderate or absent increase of testicle size, hyperplasia of Leydig's cells without spermatogenesis, and rapidly progressive signs of puberty.

Carboxyterminal peptide fragments of the beta subunit are urinary products of the metabolism of desialylated human choriogonadotropin

Previous investigations of patients with gestational trophoblastic neoplasia have shown that their urines often contain carboxyterminal peptide (CTP) fragments of the choriogonadotropin (hCG) beta-subunit as well as forms of hCG deficient in sialic acid. In order to determine whether beta-CTP fragments are among the urinary products of the peripheral degradation of desialylated hCG (as-hCG), using a continuous infusion technique, we gave highly purified as-hCG to humans. Six healthy subjects were given a loading dose of 0.8 mg of as-hCG followed by an infusion of the same preparation. An overall mean infusion rate of 62.9 micrograms/min was maintained for 6 h, and the mean serum concentration of as-hCG achieved during the infusion was 72.1 ng/ml. In all six subjects, beta-CTP fragments were the predominant immunoreactive forms of as-hCG in urine obtained during the infusion. In contrast, the urine of subjects infused with hCG has been shown to contain hCG itself, but nil beta-CTP fragments or as-hCG. After the as-hCG infusion was stopped, the excretion of the beta-CTP fragments in urine declined rapidly. There were no beta-CTP fragments detectable in sera obtained during the infusion or in sera incubated with as-hCG at 37 degrees C. After incubation with as-hCG for 4 h, the urine of normal subjects contained small amounts of beta-CTP fragments; however, the apparent proteolytic activity was too low to account for either the quantity of beta-CTP fragments produced during the infusion or the extremely low levels of as-hCG in the urine. These data demonstrate the existence in humans of a peripheral metabolic pathway that cleaves beta-CTP fragments from as-hCG and allows their excretion in urine. Thus, the frequent presence of beta-CTP fragments in the urines of patients with gestational trophoblastic neoplasia can be accounted for in part by the metabolism of the forms of hCG that bear an altered carbohydrate structure, which are prevalent in this disease.

The clinical validity of circulating tumor-associated antigens CEA and CA 19-9 in primary diagnosis and follow-up of patients with gastrointestinal malignancies

The clinical validity of monitoring the tumor markers carcinoembryonic antigen (CEA) and CA 19-9 were investigated in 602 patients with colorectal, gastric, and pancreatic carcinomas. Sensitivity and specificity of the tests were evaluated preoperatively as well as in the postoperative follow-up for early detection of disease progression and recurrence. At a 95% level of specificity as calculated from a group of 150 patients with benign diseases, the CEA test with monoclonal antibody had a preoperative sensitivity of 39% in colorectal cancer and 21% in gastric cancer. On the other hand, CA 19-9 had a sensitivity of 19% in colorectal cancer, 21% in gastric cancer, and 89% in pancreatic cancer. In the postoperative follow-up it was found that a combination of both tumor marker tests was most profitable in gastric carcinomas, yielding an increase of sensitivity from 59%-94%, showing a high degree of complementarity. The gain in sensitivity provided by the CA 19-9 test over the CEA-test in colorectal cancer was very low. The gain in sensitivity, however, provided by the CEA test over the CA 19-9 test in pancreatic carcinoma was also very low. On the basis of these results it has to be recommended that cases with pancreatic carcinoma are to be monitored most efficiently with the CA 19-9 test, whereas in cases with colorectal cancer the CEA test should be used primarily. However, in gastric cancer the combined use of CEA and CA 19-9 represents a highly valuable basis for monitoring the course of disease.

Characterization of a carboxyterminal peptide fragment of the human choriogonadotropin beta-subunit excreted in the urine of a woman with choriocarcinoma

We have observed low-molecular weight carboxyterminal fragments of the human choriogonadotropin (hCG) beta-subunit in the urines of several women with choriocarcinoma, and we have characterized one fragment in detail. Its apparent molecular weight by gel chromatography on Sephadex G-100 was 14,200. The fragment was not adsorbed to concanavalin A-Sepharose, indicating that it lacked the asparagine-linked carbohydrate groups of intact hCG beta. It was active in radioimmunoassays (RIA) using antisera either to the hCG beta carboxyterminal peptide (CTP) or to the desialylated hCG beta CTP (hCG beta as-CTP), indicating the presence of not only the hCG beta carboxyterminus but also desialylated O-serine-linked carbohydrate side chains on the fragment. It lacked luteinizing hormone/choriogonadotropin radioreceptor activity and hCG beta conformational immunoreactivity (SB6 RIA). On Sephadex G-100 gel chromatography, the elution profiles of this fragment and the hCG beta as-CTP(115-145) prepared by trypsin digestion of as-hCG were essentially indistinguishable (apparent molecular weights 14,200 and 14,000, respectively). The immunological characteristics of the fragment in both hCG beta CTP and hCG beta as-CTP RIA were indistinguishable from those of the hCG beta as-CTP(115-145) glycopeptide. Carboxyterminal fragments of hCG beta were evident in urine specimens obtained from 10 of 11 patients with choriocarcinoma but not in those obtained from normal subjects who were given an intravenous infusion of highly purified hCG. Of six pregnant women, only the one at term excreted carboxyterminal fragments of hCG beta and then only in trace amounts. We conclude that hCG beta carboxyterminal fragments, including one that is indistinguishable from the tryptic glycopeptide hCG beta as-CTP(115-145), can occur naturally in the urine of patients with choriocarcinoma.

hCG beta producing pineal choriocarcinoma

A patient is described with tumours in the region of the pineal gland and anterior hypothalamus associated with high levels of hCG beta in the serum and cerebrospinal fluid (CSF). He presented aged 19, with hypopituitarism, but persistent secondary sexual characteristics. LH immunoreactivity in serum was due to the hCG beta which probably caused the elevated level of testosterone. Following cranial irradiation the tumour became undetectable and hCG beta was eradicated from the serum and CSF. The patient later died because of an intramedullary metastasis of choriocarcinoma in the cervical spinal cord. The endocrine details of six previously reported intracranial neoplasms which have been shown to secrete hCG beta are reviewed. Only two of these involved the pineal region. Chorionic gonadotrophin production by this tumour enabled early detection of its recurrence. It is unclear how often precocious puberty is caused by tumours producing hCG beta, but patients presenting either with that problem or a pineal tumour should have circulating hCG beta measured.

The biochemical properties of urinary human chorionic gonadotropin from the patients with trophoblastic disease

Human chorionic gonadotropin (hCG) was extracted and purified from urine of normal pregnant women and patients with hydatidiform mole and choriocarcinoma using the sam methods. Both hCG-hydatidiform mole and hCG-choriocarcinoma as well as hCG-normal pregnancy was separated into alpha and beta subunits by SDS disc electrophoresis upon treatment with 2-mercaptoethanol and showed the same immunoreactivities against anti-hCG, -alpha hCG, and -beta hCG as hCG in each radioimmunoassay. In vivo bioassay, bioactivities of hCG- normal pregnancy and hCG-hydatidiform mole were approximately 7,000 IU/mg (2nd IS), while that of hCG--choriocarcinoma was only 400 IU/mg. Conversely, the receptor binding activities in vitro of hCG-chorio carcinoma was about 3 times more effective than the other 2. Although the amino acid composition of these hCG preparations were practically identical, a great difference in the carbohydrate composition was observed. The significant difference was that while sialic acid was undetectable in hCG-choriocarcinoma approximately 8.5% of sialic acid was found in hCG-normal pregnancy and hCG-hydatidiform mole. A parallel finding was that iodinated hCG-choriocarcinoma was taken up in large quantities by the liver in comparison to the ovary which differed from that observed with hCG-normal pregnancy and hCG-hydatidiform mole in Parlow rats. The present findings support the thesis that neoplastic or malignant transformation of trophoblasts may result in an alteration of the glycosylation process, especially the sialylation, in the biosynthesis of hCG rather than the translation steps.

Metabolic and renal clearance rates of purified human chorionic gonadotropin

The metabolic clearance rate (MCR) and renal clearance rate (RCR) of human chorionic gonadotropin (hCG) were measured in healthy young men and women using techniques of continuous intravenous infusion and rapid intravenous injection of unlabeled, highly purified hCG. Seven subjects received 4 d of infusion at a rate of 0.2 microgram/min, followed by an additional 4 d of infusion at 0.8 microgram/min. Mean serum levels of hCG established at these rates of infusion were 61.1 +/- 3.3 and 237 +/- 16 ng/ml, respectively (mean +/- SEM). The MCR determined at the low infusion rate was not significantly different from that determined at the higher infusion rate (1.83 +/- 0.09 vs. 1.95 +/- 0.14 ml/min per m2). The mean MCR for all subjects was 1.88 +/- 0.08 ml/min per m2. The MCR was not significantly different between men amd women (2.04 +/- 0.13 vs. 1.76 +/- 0.07 ml/min per m2). The RCR also did not vary between low and high infusion rates (0.40 +/- 0.03 vs. 0.40 +/- 0.04 ml/min per m2). The mean RCR for all subjects was 0.40 +/- 0.02 ml/min per m2. There was no difference in RCR between men and women (0.42 +/- 0.05 vs. 0.39 +/- 0.03 ml/min per m2). Six subjects were given 1.0 mg of highly purified hCG by rapid intravenous injection. Initial serum levels of hCG were 300-400 ng/ml, and the subsequent disappearance curve was multiexponential over 8-10 d. The disappearance curve of hCG in each subject was fitted to a biexponential equation. The rapid component t1/2 was 5.97 +/- 0.63 h and the slow component t1/2 was 35.6 +/- 8.0 h. We conclude that the MCR of purified hCG in man is about 2 ml/min per m2 and the RCR is 0.4 ml/min per m2; these parameters are concentration independent and do not differ significantly between healthy young men and women.

Qualitative and quantitative analyses of human chorionic gonadotropin and its subunits produced by malignant tumors

Human chorionic gonadotropin (hCG) and its subunits in plasma, urine, ascites, and tumor extracts from four patients with hCG-producing tumors (undifferentiated cell carcinoma and choriocarcinoma of the bladder, malignant teratoma of the retroperitoneum, and pancreatic carcinoma) were measured by the radioimmunoassays specific to each component. While both free alpha and beta subunits as well as the whole molecule of hCG were found in all these samples, the proportion of beta subunit was much higher in these tumor extracts than in the placental extracts. Since the alpha and beta subunits are known to be translated from separate mRNAs, such increase of subunit is probably due to the predominant increase of mRNA encoding beta subunit of hCG in the hCG-producing tumors. Gel filtration of the extracts of these four tumors on Sephadex G-100 and G-150 columns demonstrated a heterogeneity of hCG, alpha, and beta subunits in these tumor extracts, and the elution profiles of plasma, urine and tumor extracts were slightly different. Lower molecular weight forms of hCG and its beta subunit were present in all urine samples. The significance of these heterogeneities remains to be elucidated.

Circulating choriogonadotropin beta subunit in a patient with primary amenorrhea and embryonal ovarian carcinoma

A 20-year-old patient, phenotypically female, genotypically male, who had previously sought medical attention for primary amenorrhea, developed an embryonal carcinoma in the right gonad. Selective formation of the beta subunit of choriogonadotropin was demonstrated by positive test results on native serum and after gel filtration with a classical "beta-HCG" assay and a specific assay for the beta subunit, but negative results with a specific assay for choriogonadotropin. The concentrations of placental lactogen, alpha-fetoprotein and choriogonadotropin alpha subunit were normal. This case illustrates the necessity for early diagnosis of primary ovarian insufficiency in cases of primary amenorrhea. The results indicate that, for the detection of certain neoplastic disorders, the lower specificity of the choriogonadotropin assay introduced in 1972 by Vaitukaitis and coworkers [25]--reacting equally well with choriogonadotropin and with free beta subunit--may have advantages over the more specific assays for choriogonadotropin and for the beta subunit described by Franchimont et al. [8,28,29]. The availability of the latter assays, however, facilitates the identification of the immunoreactive material found with the former assay. The ambiguity of the present nomenclature for "beta-HCG" assay is pointed out.

Ectopic production of human chorionic gonadotropin (hCG) by neoplasms: the value of measurements of immunoreactive hCG in the urine as a screening procedure

Immunoreactive human Chorionic Gonadotropin (hCG) was measured in serum and urine extracts from patients with malignant disease using a radioimmunoassay that detects efficiently hCG and its betasubunit. Of the 70 patients examined, 12 (17.1%) were positive for hCG in serum and 31 44.3%) in urine. Eleven patients who were positive in serum were also positive in urine; 20 patients (28.6%) were positive only in urine. Sephadex G-100 chromatography of urine from two serum-negative and urine-positive patients showed that the hCG immunoreactive material in the urine of these patients was mostly a molecular species smaller than hCG and hCG-beta. The nature of this molecule(s) is unknown and is called here metabolite(s) "X" of hCG-beta. The urine of 2 patients who where positive for hCG in both serum and urine contained considerable amount of metabolite(s) "X" as well as the native hCG-beta subunit, which was present also in the serum of these 2 patients. The metabolite(s) "X" was also shown by chromatography in the urine of a pregnant woman. It is concluded that the ectopic production of hCG is found more than twice as frequently in urine as compared to when serum alone is examined. The urine of serum-negative tumor patients can be positive for hCG because of the presence in it of the metabolite(s) "X" of hCG-beta or hCG which presumably circulates in the blood of these patients at non-detectable levels.

The immune response to hCG-beta subunit in rats and the effects of active immunisation on their fertility

Immunogenicity of hCG beta subunit (beta-hCG) was investigated in female rats using a variety of immunisation schedules and the effects of active immunisation on fertility were studied. Antibody production to beta-hCG conjugated to tetanus toxoid was pronounced and was not enhanced by the use of adjuvants or presensitisation to tetanus toxoid carrier. Nor was it diminished by using half the amount of beta-hCG-TT conjugate. Boosting resulted in a marked secondary response producing high titre antibody over a prolonged period. Partial or complete infertility occurred in the beta-hCG immunised rats, dependent on which immunisation schedule was employed, implying a threshold titre of antibody required to interfere with pregnancy. No significant effect was observed on the oestrous cycle of the immunised rats or on the gross morphology of their progeny. The results are discussed in relation to the hormonal control of reproductive function in the rat, and the possible application of immunisation against beta-hCG to human fertiliyt.

Peptide hormones as tumor markers

Ectopic production and secretion of hormones by a wide variety of tumors were initially recognized by signs and symptoms of excess circulating biologically active hormone. With the development of more sophisticated and sensitive techniques, it has become apparent that not all tumors secrete biologically active hormones. Some altered forms of polypeptide hormones may be in very high concentrations immunologically but be inactive biologically. On the other hand, polypeptide hormones may circulate at concentrations too low to induce clinical signs and symptoms. Consequently, new ectopic humoral syndromes have been recognized and the incidence of previously described syndromes has become considerably greater than previously recognized. Every hormone known to be normally secreted by endocrine organs or the placenta has been documented to be secreted ectopically by a wide variety of tumors. Moreover, several of those hormones may be used as biochemical markers of malignancy for both screening and monitoring of patients with documented or suspected tumors.

Presence in normal human testes of a chorionic-gonadotropin-like substance distinct from human luteinizing hormone

The high rate of human chorionic gonadotropin production by testicular tumors caused us to investigate the possibility that normal human testes contain small amounts of that substance. Extracts of human testes obtained at autopsy demonstrated parallel inhibition curves to the human chorionic gonadotropin standard in a radioimmunoassay specific for the hormone. The immunoreactive material was adsorbed onto concanavalin A, a reaction characteristic of glycoproteins, and was eluted within the chorionic gonadotropin range on Sephadex G-100 column chromatography. Solubilized receptor proteins for the hormone could not be identified in the extracts. The demonstration that the normal human testes contain a glycoprotein similar or identical to human chorionic gonadotropin suggests that the fetal genome responsible for production of the hormone during pregnancy is not completely suppressed in the adult. Excessive productton of this glycoprotein may account for the high levels of human chorionic gonadotropin reported in the serum of patients with germ-cell tumors of the testes.

Aberrant hormone activity by tumors of gynecologic importance

Increasing numbers of endocrine active tumors are being reported. The production of hormonal substances not generally associated with the tissues involved may directly or indirectly concern the gynecologist. Identification of these occurrences may be important in the diagnosis of occult neoplasms or obscure tumor effects. In addition, observation of the level of aberrant hormone secretion may be important therapeutic and prognostic measure. Detection may result from the investigation of apparent inappropriate and endocrine syndromes or routine screening in cases of known tumors. Proof of the actual production of hormone by the tumors and complete identification of the material in question generally requires extensive biologic, chemical, physical, and immunologic investigation. The most likely mechanisms for aberrant hormone production by tumors are derepression of the genome or the occurrence of chance biosynthetic anomalies coincident with neoplastic nuclear alterations. Endocrine active substances of interest to the gynecologist produced under these circumstances include gonadotropin, lactogens, thyrotropins, and adrenocortico-tropin, as well as calcium-mobilizing and erythropoietic substances.