# BUILDING BONE IN OSTEOPOROSIS WITH PTH AND ESTROGEN

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 1993 · $248,846

## Abstract

At present, there are no drugs approved for the treatment of
osteoporosis.  While antiresorptive agents appear to be effective in
preventing the disease, it is generally agreed that their ability to
increase bone mass is modest at best.  In order to be viable in the
therapy of established osteoporosis, agents will need to have a strong
anabolic effect.

Studies in vivo in man and animals show that parathyroid hormone (PTH)
administered in relatively low doses intermittently stimulates bone
formation.  This is in contrast to its well established ability to
stimulate bone resorption when it is given in high doses continuously.
The mechanisms of those paradoxical effects of PTH are poorly understood,
but the results of recent studies in vitro suggest that the anabolic
effects may be related to the ability of PTH to stimulate osteoblasts to
produce insulin-like growth factor (IGF-I).

Evidence has accumulated that estrogen acts directly to decrease
osteoclastic bone resorption and may also have effects on the osteoblast
that are essential to normal bone formation.  It is well established that
estrogen replacement therapy (ERT) prevents the accelerated bone loss
that occurs in most women after the menopause.  Furthermore, ERT, by
definition, seeks only to restore normal estrogenic function, which when
present aids in maintaining both bone and mineral balance.

The purpose of the proposed investigation is to determine the efficacy of
the combined administration of synthetic human parathyroid hormone
fragment, 1-34, (HPTH 1-34) and estrogen- progesterone replacement in the
treatment of postmenopausal women with osteoporosis.  We hypothesize that
such treatment will increase bone mass and effect a distribution of
vertebral bone mineral that favors increased strength more than treatment
with individual constituent agents alone.

The osseous effects of combined PTH 1-34 - estrogen therapy will be
monitored with conventional dual energy x-ray absorptiometry measurements
of the spine, hip and forearm, as well as a new, experimental approach
using three-dimensional quantitative computed tomography to assess
vertebral bone mineral distribution.  Other outcome measures will include
serial measurement of bone markers including serum alkaline phosphatase
and osteocalcin, and urine pyridinoline crosslinks.

## Key facts

- **NIH application ID:** 3122885
- **Project number:** 1R01AG010925-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **SAM.gov UEI:** KMH5K9V7S518
- **Principal Investigator:** CLAUDE D ARNAUD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $248,846
- **Award type:** 1
- **Project period:** 1993-06-11 → 1998-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3122885

## Citation

> US National Institutes of Health, RePORTER application 3122885, BUILDING BONE IN OSTEOPOROSIS WITH PTH AND ESTROGEN (1R01AG010925-01A1). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3122885. Licensed CC0.

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