# EFFECT OF HORMONES ON BONE RESORPTION IN VITRO

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 1987 · $186,657

## Abstract

The major objective of the proposed studies is to further examine the
concept that calcium flux plays an important role in initiating the actions
of calcemic hormones on bone.  We will utilize calcium-load liposomes to
increase intracellular calcium.  Liposome effects will be studied in the
presence and absence of calcemic hormones (parathyroid hormone,
prostaglandins, vitamin D metabolites).  Hormonal effects on early events
which may either a) initiate calcium translocation or b) produce rapid
calcium-dependent changes will be investigated in bone organ cultures and
bone cells.  These will include investigations of the effects of calcemic
hormones on phosphoinositol breakdown and on steady state levels of various
phospholipids, including phosphatidylcholine, phosphatidylserine,
phosphatidylethanolamine, phosphatidylinositol and polyphosphoinositides.
Evidence for calcium-dependent kinases and calcium-dependent
phosphorylation will be sought in bone; if these processes are present, we
will examine their responses to calcemic hormones.  In other studies we
will continue to utilize the fetal rat bone organ culture system as a
bioassay for vitamin D analogs and for 1.25-(OH)2vitamin D3 in serum and
tissue extracts.  A number of new metabolites and analogs of interest will
be examined.  The putative 1,25-(OH)2D which has been found to be produced
by a number of cell cultures will be tested for biological activity on
bone.  We hope by these studies to gain a better understanding of the
mechanisms of action of agents which are either etiologic factors in
diseases of bone or potentially useful in their treatment.

## Key facts

- **NIH application ID:** 3154737
- **Project number:** 5R01AR011262-21
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **SAM.gov UEI:** KG76WYENL5K1
- **Principal Investigator:** PAULA H STERN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $186,657
- **Award type:** 5
- **Project period:** 1978-07-01 → 1988-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3154737

## Citation

> US National Institutes of Health, RePORTER application 3154737, EFFECT OF HORMONES ON BONE RESORPTION IN VITRO (5R01AR011262-21). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3154737. Licensed CC0.

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