# HORMONE RESPONSES IN ISOLATED BONE CELLS

> **NIH NIH R01** · UNIVERSITY OF COLORADO · 1987 · $168,641

## Abstract

Data from several laboratories indicate that bone contains and/or
secretes several transforming and non-transforming growth
activities, and Sm-C (IGF-1) like material.  Since the development
and maintenance of bone tissue is dependent both on osteoblast
activity and the timely replacement of aged osteoblasts from the
precursor pool, a role for these growth factors in bone cell
proliferation and possibly differentiation is indicated.

Our interest in bone cell differentiation has in the past led us to
attempt separation of bone cells with different phenotypes.  We
examined the cellular source and target cells for these bone
derived growth  factors, and concluded that the osteoblastic cells
released late during collagenase digestion of bone are a major
source of growth activity when compared to early release less
osteoblastic cells, producing at least two growth inducing factors
of MW 24,000 and 11,000 daltons, and a material that appears to
be immunologically related to Sm-C (IGF-1).  We now plan to
compare and purify the growth inducing activities present in
osteoblasts bone tissue and medium conditioned by osteoblasts.
We also propose to test their effects on proliferation and
differentiation of three classes of bone cells that we have
succeeded in isolating using bone matrix digestion with pure
collagenase, followed by a collagenase protease mixture, to
prepare early released fibroblastic cells, intermediate cells, and
late released osteoblastic cells.  In addition to the traditional
osteoblastic characteristics (alkaline phosphatase, PTH
responsiveness) we have demonstrated phenotypic differences
among these three classes of bone cell using biochemical markers
such as EGF receptor number and affinity and endogenous growth
factor production.  The latter two classes of cells have different
numbers of high affinity EGF receptors.  We plan to further
separate these two cell types using flow cytometry to select cell
groups on the basis of total EGF and fluorescent anti-EGF
binding.  We will study whether the biochemical characteristics of
these cells permit classification as osteoblasts, intermediate
osteoblasts and/or non-osteoblasts.

Finally the ability of less-or-non-osteoblastic bone cells (obtained
by the above procedures) to acquire the osteoblastic phenotype
after various treatments and/or exposure to bone growth factors
will be followed.  The ultimate aims of these studies are 1) to
isolate homogeneous bone cell populations in order to 2) study
bone cell development and 3) the role of endogenous growth
factors in this process.

## Key facts

- **NIH application ID:** 3156506
- **Project number:** 2R01AR033098-05
- **Recipient organization:** UNIVERSITY OF COLORADO
- **SAM.gov UEI:** RH87YDXC1AY5
- **Principal Investigator:** GLENDA L WONG
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $168,641
- **Award type:** 2
- **Project period:** 1983-04-01 → 1992-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156506

## Citation

> US National Institutes of Health, RePORTER application 3156506, HORMONE RESPONSES IN ISOLATED BONE CELLS (2R01AR033098-05). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3156506. Licensed CC0.

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