# ENDOSTEAL BONE VOLUME REGULATION AND OSTEOPOROSIS

> **NIH NIH R01** · LOMA LINDA UNIVERSITY · 1988 · $127,533

## Abstract

The proposed work is devoted to studies of the regulation of endosteal bone
volume.  Such studies are essential to our overall long-term goal, which is
to cure and prevent osteoporosis.  Our position is that in osteoporosis,
endosteal bone volume is lost, that faulty endosteal bone volume regulation
accounts for this bone loss, and that this defect may involve our putative
coupling factor.  Studies of the effects of calcium regulating hormones at
the endosteum led to the concept that the coupled increase in formation
subsequent to an increase in resorption was an endosteal counter-regulatory
measure mediated by a coupling factor and functioning to maintain endosteal
bone volume in opposition to calcium regulating hormones.  We will test our
hypothesis, by means of in vitro studies, that during bone resorption a
coupling factor is liberated either from bone matrix or from endosteal bone
cells.  The factor(s) will then be purified; its secretion, specificity and
action will be studied.  In addition, we will study the regulatory
interactions among the four bone cell populations (committed and mature
osteoblasts and osteoclasts) in response to a perturbation of only one of
these cell populations.  The latter will include studies of the ia rat in
which the activity of the osteoclast population is probably exclusively
impaired, and studies of treatment with cis-hydroxyproline, an agent that
may exclusively inhibit the activity of the osteoblast population.  For
these studies we will develop a tritiated thymidine kinetic method to
measure cell production rates of osteoblasts and osteoclasts which will be
measures of the committed osteoblast and committed osteoclast populations
respectively.  This method also will be applied to the studies of the W/Wv
mouse which has a stem cell defect and which may provide a means to
determine if the coupling of osteoblast number to osteoclast number, a
finding which we have documented, operates at the stem cell level.

## Key facts

- **NIH application ID:** 3155959
- **Project number:** 5R01AR031062-06
- **Recipient organization:** LOMA LINDA UNIVERSITY
- **SAM.gov UEI:** SZAKFNU35ZX5
- **Principal Investigator:** DAVID J BAYLINK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $127,533
- **Award type:** 5
- **Project period:** 1981-08-01 → 1988-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3155959

## Citation

> US National Institutes of Health, RePORTER application 3155959, ENDOSTEAL BONE VOLUME REGULATION AND OSTEOPOROSIS (5R01AR031062-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3155959. Licensed CC0.

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