For many years, osteoporosis in women was equated with estrogen deficiency. The recent articles by Zaidi and colleagues offer a new challenge to the estrogen-deficiency-osteoporosis hypothesis by showing that follicle-stimulating hormone (FSH) stimulates osteoclastic bone resorption perhaps through tumor necrosis factor-alpha (TNF-alpha). These authors, however, neglected to mention bone abnormalities and high testosterone levels that were previously shown in FSH-receptor knockout and other modified mice. It is also possible that they have overemphasized potential relationships of these new data with human bone loss. Despite these fascinating data, the paradigm of FSH causing hypogonadal bone loss is not yet ready to displace the estrogen-deficiency-osteoporosis paradigm, although that model already faces considerable challenge.
Prior JC FSH bone resorption physiology, follicle stimulating hormone osteoclastic bone loss, FSH receptor knockout mice bone abnormalities, estrogen deficiency osteoporosis hypothesis challenge, Zaidi FSH osteoclast TNF-alpha bone resorption, hypogonadal bone loss FSH versus estrogen paradigm, reproductive hormones bone metabolism women, FSH stimulated bone resorption tumor necrosis factor, Prior JC progesterone bone density estrogen critique, menopausal bone loss hormonal mechanisms FSH
PMID 17141571 17141571 DOI 10.1016/j.molmed.2006.11.004 10.1016/j.molmed.2006.11.004 Prior et al. 2006, Prior 2006
Cite this article
Prior, J. C. (2007). FSH and bone--important physiology or not?. Trends in molecular medicine, 13(1), 1-3. https://doi.org/10.1016/j.molmed.2006.11.004
Prior JC. FSH and bone--important physiology or not?. Trends Mol Med. 2007;13(1):1-3. doi:10.1016/j.molmed.2006.11.004
Prior, J. C. "FSH and bone--important physiology or not?." Trends in molecular medicine, vol. 13, no. 1, 2007, pp. 1-3.
Kalyan S et al., 2010·Crit Rev Eukaryot Gene Expr·
Women's menstrual cycles and bone remodeling are linked in part by their co-dependency on the stressand resource-associated variables that govern both of their cyclical natures. Therefore, it is not surprising that evolution has resulted in the same signaling molecules and pathways that regulate normal ovarian function to be involved in bone remodeling and turnover. This review will first provide an overview of the normal menstrual cycle, its modification by age and ovulatory disturbances, and how it parallels bone remodeling. Epidemiological and clinical evidence will be presented that link bone remodeling, strength, and fractures with women's history of reproductive and menstrual cycle characteristics. This combined evidence will then be presented alongside a synthesis of current concepts derived from basic science investigations focused on understanding the molecular mechanisms underlying the influence of ovarian factors on bone physiology. Osteoporosis is a significant source of morbidity for older women. The data presented in this review suggest that a woman's reproductive cycle and ovulatory characteristics foreshadow the future health of her bones. More importantly, identifying the key mechanisms underlying reproductive and bone health would not only provide essential preventative strategies, but may also uncover attractive targets for the treatment of osteoporosis.
Popat VB et al., 2008·Ann N Y Acad Sci·
Open Access
Menstruation is the cyclic, orderly sloughing of the uterine lining on account of the interactions of hormones produced by the hypothalamus, pituitary, and ovaries. There is a tendency among parents and clinicians to view oligo-amenorrhea as a normal variant in the teen years. In fact, the 95th percentile for the time interval between cycles is 90 days. Thus, it is abnormal for an adolescent to be amenorrheic for greater than 3 months, even in the early gynecologic years. Identification of abnormal menstrual patterns throughout adolescence may permit early identification of potential health concerns for adulthood. Few problems in gynecologic endocrinology are as complex or challenging to the clinician as amenorrhea. However, thorough evaluation of menstrual cycle disorders in adolescence provides a window of opportunity for early diagnosis and treatment of conditions affecting the hypothalamic-pituitary-ovarian (HPO) axis. Here we discuss a systematic approach to the evaluation and treatment of amenorrhea in adolescents who do not have androgen excess. There is strong evidence that estrogen deficiency is a risk factor for later development of osteoporosis and hip fracture. Delay in the evaluation and treatment of disordered menses in some cases may contribute to reduced bone density. Both patients and clinicians need to view the ovary as an important endocrine organ that helps maintain health, especially bone health.
To the Editor: In their recent article, "Characterization of Perimenopausal Bone Loss," Recker and colleagues present unique longitudinal bone mineral density (BMD) and hormonal data.1 We acknowledge the work involved in recruiting, motivating, and continuing to follow 75 women each for an average of 8 years. The data from this study are an important contribution to our knowledge of bone changes through the natural perimenopausal transition. Unfortunately, these authors have chosen to reduce the complex endocrinological and physiological changes of perimenopause2 to one idea—"estrogen deprivation." Our first concern is that "estrogen deprivation" or "depletion" is not an adequate concept with which to explain the rapid bone loss during perimenopause. The author's own data show that 50% of spinal BMD loss has occurred by 6 months before the final menstrual period at which time estradiol levels are not lower than in the so called "estrogen replete" group. In this study, perimenopausal bone loss appears to begin approximately 3 years before the final menstrual flow, which is about the time when menstrual cycles become irregular.3 Several other studies also show accelerated rates of perimenopausal bone loss.2, 4, 5 During these later phases of perimenopause, estradiol levels can be very high and certainly are not consistently low.2, 6, 7 If estradiol levels are not low in perimenopause, how can we explain the rapid bone loss? First, estradiol levels vary widely.2 Perhaps, acute drops in estradiol levels (often from abnormally high values) cause increased bone resorption much like that which has been shown to occur within seven days of premenopausal ovariectomy.8 A second possibility is that perimenopause causes psychosocial stress.9 Social stress coupled with high estradiol levels in men have been experimentally shown to cause increased cortisol levels10 that are known to be negative for bone. Finally, ovulatory changes that increase as women progress through perimenopause,11 are associated with accelerated cancellous bone loss, despite normal estradiol levels and regular cycles in premenopausal women.12 Replacement of luteal phases with cyclic progestin in a double-blind randomized study in premenopausal women with abnormal cycles caused an important positive change in spinal BMD.13 As a mechanism to allow use of all of their data, the authors labeled "estrogen replete" those women who continued to menstruate as well as those who started hormone therapy before menopause. It seems odd to us to combine data from three women who have undergone ovariectomy and seven women on exogenous hormone therapy with 10 preor perimenopausal women. The estrogen deprivation hypothesis has led the authors to overlook important physiological differences within this group. We request that the data for the 10 untreated preor perimenopausal women be provided and that we be told whether or not they continued to menstruate regularly. In women's life cycle, low levels of estrogen are as natural for menopausal women as for toddlers. To label menopause as a hormone deficiency condition is to ignore the normal hormonal pattern of women's lives. Recker and colleagues suggest that "hormone replacement therapy" should "begin as early as 2 years before the last menstrual period." Although we acknowledge that vasomotor symptoms commonly begin in perimenopause and have a very negative impact on quality of life, we suggest that progesterone would be a more appropriate therapy. Progesterone is truly low at this phase of perimenopause11 and is effective for night sweats/hot flushes. We fear that prescription of estrogen to women in late perimenopause may have negative consequences in both the short and the long-term. In the short term, it may exacerbate symptoms such as breast tenderness, headaches, and fluid retention. In the long term, having experienced side effects from estrogen treatment these women may refuse it when they are menopausal, a time when it has the potential to be valuable therapy. In summary, this important study is flawed because it relies on a clearly inadequate "estrogen deprivation" concept as the sole explanation for differences found in the prospective data from midlife women.
This review presents data to suggest that postnatal estradiol and progesterone replacement therapy may be beneficial in preterm infants. During pregnancy, maternal plasma levels of estradiol and progesterone increase up to 100-fold compared to the nonpregnant status. The fetus is also exposed to these increasing hormone levels. After delivery, estradiol and progesterone levels drop by a factor of 100 within 1 day. Whereas this is a physiological condition for an infant born at term, preterm delivery means withdrawal from the placental supply of these hormones at an earlier developmental stage. Seventy years ago, the idea was raised that preterm infants may benefit from the replacement of estrogens. Studies in which estrogen was injected subcutaneously showed only a slightly better bodyweight gain compared to placebo-treated controls and therefore routine use was not established. The effective treatment of postmenopausal osteoporosis with hormone replacement therapy led to a pilot study of estradiol and progesterone therapy to prevent osteopenia of prematurity. The highest median bone mineral accretion rate was found in the replacement group when the supplementation with calcium and phosphorus was also sufficient. None of the previous studies dealing with estrogen replacement controlled for achieved plasma levels of estradiol in the infants. In our controlled randomised pilot study with 30 preterm infants (15 in each group), we aimed to maintain intra-uterine plasma levels of estradiol and progesterone. Preterm infants with replacement of estradiol and progesterone for 6 weeks postnatally showed trends to higher bone mineral accumulation. In addition, a trend towards a lower incidence of chronic lung disease was found. Neurodevelopmental follow-up showed normal psychomotor development in infants given estradiol and progesterone, whereas the untreated infants (controls) showed a trend towards delayed development. Recent research emphasises that estradiol and progesterone may be important for brain development. Thus, while there is data indicating that postnatal estradiol and progesterone replacement therapy may be beneficial in preterm infants, experience with this new therapy is limited and extensive research is needed to address the potential benefits and to rule out adverse effects.