# BIOSYNTHESIS AND SECRETION OF HCG BY HUMAN TROPHOBLASTS

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 1988 · $250,043

## Abstract

The specific aims of our research are:  (1)\to purify the uncombined and
combined subunits of human chorionic gonadotropin (hCG) subunits produced
by malignant trophoblastic cells and normal placenta; (2)\to characterize
biochemically the hCG subunits produced by these tissues; and (3)\to
determine the rate-limiting steps involved in the processing and secretion
of hCG subunits by these tissues.  Methods include pulse-chase labeling of
cultured trophoblastic cell lines and organ cultures of normal placenta
with radioactive amino acids and carbohydrates (in the presence and absence
of various glycosidase inhibitors and drugs that affect intracellular
cation and pH gradients); determination of carbohydrate structure and amino
acid composition; and sequence analysis of the glycoprotein subunits of hCG
produced by these tissues.  Data obtained to date indicate that:  (1)\free
hCG-beta subunit is present in cells and media from cultured
choriocarcinoma cells and placental explants and in the sera of pregnant
women and of patients with choriocarcinoma; (2)\free alpha, but not
hCG-alpha, contains an O-linked oligosaccharide chain; (3)\there is a pH
gradient, apparently within the Golgi apparatus, that regulates the
oligosaccharide processing and secretion of hCG and its free subunits; and
(4)\the kinetics of secretion of free alpha, free beta, and hCG dimer are
similar even though the kinetics of processing of their N-linked
oligosaccharides are somewhat different.  Long-term objectives are to learn
what controls the secretion of hCG from normal and malignant trophoblastic
cells and to determine what differences, if any, exist between the
glycoprotein hormone subunits produced by normal and malignant cells.  The
results of these studies will have potential significance for the use of
hCG subunits as tumor markers and in fertility control.  (A)

## Key facts

- **NIH application ID:** 3170842
- **Project number:** 5R01CA032949-07
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **SAM.gov UEI:** GNJ7BBP73WE9
- **Principal Investigator:** RAYMOND W RUDDON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $250,043
- **Award type:** 5
- **Project period:** 1982-08-01 → 1990-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3170842

## Citation

> US National Institutes of Health, RePORTER application 3170842, BIOSYNTHESIS AND SECRETION OF HCG BY HUMAN TROPHOBLASTS (5R01CA032949-07). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3170842. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*