In biological fluids, hCG and its free alpha- (hCG alpha) and beta-subunits (hCG beta), occur in multiple forms. These various forms differ at the molecular level primarily in glycosylation, but also differ in protein backbone modifications corresponding to the urinary low molecular weight fragment of the hCG beta-subunit (beta-core fragment). This microheterogeneous nature can be demonstrated ...

The pregnancy hormone human chorionic gonadotropin (hCG) is also present at low concentrations in plasma and urine of men and nonpregnant women. hCG immunoreactivity occurs in various molecular forms: Besides the intact hCG heterodimer, considerable amounts of proteolytically cleaved forms, free subunits, and fragments are found in plasma and urine. Especially in urine, proteolytic fragments co...

A photoaffinity derivative of human chorionic gonadotropin (hCG-N-hydroxysuccinimidyl-4-azidobenzoate (hCG-HSAB) ) was used to identify components of the lutropin (LH)/hCG receptor in plasma membranes prepared from pregnant mare serum-pretreated rat ovaries. In intact plasma membranes, the Kd for hCG (1 X 10(-10) M) was the same with both 125I-hCG and 125I-hCG-HSAB, and the binding capacity for...

The nature of the substance with thyroid-stimulating activity (TSA) present in human chorionic gonadotropin (hCG) prepared from pregnancy urine was investigated. In the mouse thyrotropin bioassay, the characteristic maximum of blood radioactivity obtained with the TSA in hCG preparations occurred after that obtained with pituitary thyrotropin (hTSH) but before that obtained with long-acting thy...

Testosterone is produced in male rats by the action of luteinizing hormone (LH), an anterior pituitary hormone which interacts with receptors on Leydig cells (testes) to activate adenylate cyclase. A most frequently used agonist for LH is human chorionic gonadotropin (hCG), a hormone synthesized by the placenta during the early stages of pregnancy. Like LH, it is a heterodimer consisting of two...

OBJECTIVE To compare serum human chorionic gonadotropin (hCG) titers using 2 commercially available hCG immunoassays in patients with gestational trophoblastic neoplasia (GTN). STUDY DESIGN A total of 213 serum samples from 39 patients with uneventful moles and 697 serum samples from 17 patients with low-risk and high-risk GTN were obtained and subsequently measured with both the hCG C-termin...

The placenta may be involved in the regulation of the maternal thyroid function during pregnancy. As human chorionic gonadotropin (hCG) is a primary protein from the placenta, we examined the thyrotropic activity of hCG and its derivatives using tissue culture and monolayer cell culture of human thyroid glands. The TSH receptor preparation was made from thyroid tissues, and its binding affinity...

Trisomy 21 is associated with high maternal serum concentrations of intact human chorionic gonadotrophin alpha(HCG) and free beta-HCG whereas these concentrations are markedly decreased in trisomy 18. In this study, we investigated the effect of trisomy 21 and 18 on endogenous HCG concentrations and luteinizing hormone (LH)/HCG receptor expression in placental villous tissue in eight trisomy 21...

Human chorionic gonadotropin (hCG) is a glycoprotein hormone comprising 2 subunits, alpha and beta joined non covalently. While similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents, rather than as a single molecule like LH and the other glycoprotein hormones. These are regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglyc...