Related Experiment Video
Updated: Aug 12, 2026
06:18
An In Vivo Estrogen Deficiency Mouse Model for Screening Exogenous Estrogen Treatments of Cardiovascular Dysfunction After Menopause
Published on: August 13, 2019
[The preventive effect of HRT on postmenopausal bone loss]
1Department of Gynecology, Aichi Prefectural Center of Health Care.
Nihon Sanka Fujinka Gakkai Zasshi
|May 1, 1992
Summary
Hormone replacement therapy (HRT) effectively prevents postmenopausal bone loss. Conjugated estrogen administration significantly increased bone mineral content in women, demonstrating HRT
Area of Science:
- Endocrinology
- Gerontology
- Bone Metabolism
Background:
- Postmenopausal bone loss is a significant health concern.
- Hormone replacement therapy (HRT) is a potential intervention.
- Long-term effects of HRT on bone density require investigation.
Purpose of the Study:
- To investigate the preventive effect of HRT on postmenopausal bone loss.
- To evaluate the efficacy of conjugated estrogen in maintaining bone mineral content.
- To compare the effects of HRT in new users versus long-term users.
Main Methods:
- A 5-year study involving postmenopausal women.
- Administration of 0.625mg/day conjugated estrogen.
- Measurement of bone mineral content using microdensitometry (MD).
- Comparison between HRT groups (new users, long-term users) and a control group (no HRT).
Main Results:
- The control group showed a significant decrease in bone mineral content (9.28% decrease).
- Group I (new HRT users) showed a significant increase in bone mineral content (102.91% of baseline).
- Group II (long-term HRT users) showed a slight increase (100.26% of baseline).
- Both HRT groups demonstrated significantly better outcomes than the control group.
Conclusions:
- HRT is highly effective in preventing postmenopausal bone loss.
- New users of HRT experienced greater bone mineral density increases compared to long-term users.
- HRT offers significant benefits for bone health in postmenopausal women.
Related Concept Videos
01:40Bone Remodeling
Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain bone mass and calcium homeostasis. While mechanical stress can stimulate turnover as part of the normal maintenance and reparative process, several hormones also regulate bone remodeling.
01:31Osteoclasts in Bone Remodeling
Osteoclasts are cells responsible for bone resorption and remodeling. They originate from hematopoietic progenitor cells present in the bone marrow. Numerous progenitor cells fuse to form multinucleated cells, each with 10-20 nuclei. A single osteoclast has a diameter of 150 to 200 µM. These cells have ruffled borders that break down the underlying bone tissue and release minerals such as calcium into the blood in bone resorption. Osteoclasts cling to bones with their ruffled edges during bone...
01:29Bone Disorders
Aging and its effect on bone remodeling is the most common cause of bone disorders. In young and healthy people, bone deposition and resorption happen at an equal rate to maintain optimal bone health.
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:17Hormones and Bone Tissue
The endocrine system produces and secretes hormones, which interact with the skeletal system. These hormones control bone growth, maintain bone once it is formed, and remodel it.
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
Hormones That Influence Osteoblasts and/or Maintain the Matrix
Several hormones are necessary for controlling bone growth and maintaining the bone matrix. The pituitary gland secretes growth hormone (GH), which, as its name implies, controls bone growth. This happens in several ways: first, it triggers chondrocyte...
01:25Role of Vitamins in Maintaining Bone Health
The growth and maintenance of bone are regulated by a combination of nutritional factors, including vitamins, such as vitamin A, B12, C, D, and K.
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
Vitamin A
Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.
Vitamin B12
Vitamin B12 acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B12 plays a role...
01:28Menopause
Menopause, a natural biological process marking the end of a woman's fertility, typically occurs between the fifth and sixth decade of life. This phase is characterized by the exhaustion of the ovarian follicle pool, leading to less responsive ovaries despite the high levels of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH). The consequential decrease in estrogen production results in symptoms like hot flashes, heavy sweating, headaches, hair loss, muscle pains, vaginal...