Calcitonin and the Calcium-Regulating Hormones in Postmenopausal Women: Effect of Oestrogens

Stevenson, JohnC.; Hillyard, C. J.; Abeyasekera, G.; Phang, Kheng Guek; MacIntyre, I.; Campbell, Stuart; Townsend, P. T.; Young, O.; Whitehead, MI

doi:10.1016/s0140-6736(81)91973-5

Cited by 173 publications

(37 citation statements)

References 19 publications

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“…We indeed demonstrated that es trogen replacement therapy in healthy postmenopausal women did not stimulate CT secretion, as claimed by oth ers [3], but, on the contrary, induced a slight reduction in basal CT levels, consistent with the well-known inhibitory effects of estrogens on bone turnover [16]. Another study in male renal stone formers also supports our hypothesis.…”

Section: Osteoporosis and Estrogen Replacement Therapy: Effects On Ctsupporting

confidence: 87%

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Calcitonin: From the Determination of Circulating Levels in Various Physiological and Pathological Conditions to the Demonstration of Lymphocyte Receptors

Body

1993

Horm Res

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This article summarizes our main findings concerning calcitonin (CT) physiology and pathology. We have devised a simple extraction method of circulating CT that much improves assay sensitivity and specificity for the measurement of the CT monomer. Combining this extraction method with newer immunometric assays permits a sensitive and exclusive measurement of monomeric CT. CT secretory capacity is 4-5 times lower in women than in men, but there is no significant fall in basal or calcium-stimulated CT levels with age. We also found no evidence for CT deficiency in postmenopausal osteoporosis. On the contrary, changes in circulating CT levels appear to be secondary to the changes in bone turnover, whether in postmenopausal osteoporosis, after estrogen replacement therapy or in renal stone formers. We found a marked CT deficiency after thyroidectomy, radioactive iodine treatment and in patients with congenital hypothyroidism or autoimmune primary hypothyroidism. The deleterious effects of CT deficiency on bone mass remain, however, essentially speculative. Lastly, we have found specific and high-affinity CT receptors on normal circulating T-lymphocytes. Their meaning remains to be demonstrated but we have recently found that the osteolytic cytokines IL-1 and IL-6 are able to markedly reduce the number of CT receptors on T-lymphocytes without changing their affinity.

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Section: Osteoporosis and Estrogen Replacement Therapy: Effects On Ctsupporting

confidence: 87%

“…CT secretion [3]. On the other hand, it was assumed that CT had an important role in the proper utilization of dietary calcium [4], However, most data had been ob tained with poorly sensitive and specific radioimmunoas says.…”

mentioning

confidence: 99%

Calcitonin: From the Determination of Circulating Levels in Various Physiological and Pathological Conditions to the Demonstration of Lymphocyte Receptors

Body

1993

Horm Res

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“…This is supported by the observation that in reproductive-age women, mean plasma calcitonin was three to five times higher in women who were pregnant or taking oral contraceptives, compared with nonpregnant women who did not use oral contraceptives (388). Moreover, treatment of postmenopausal women with either estradiol or a synthetic estrogen (ethinylestradiol) resulted in a significant increase in plasma calcitonin (877).…”

Section: Calcitoninmentioning

confidence: 79%

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

Kovacs

2016

Physiological Reviews

383

524

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During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ϳ30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.

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“…This suggests that estrogen concentrations are important determinants (risk factors) of the rate of bone remodelling around the time of menopause, and that increased remodelling (BGP as a marker) due to a relative deficiency of estrogen leads to increased bone loss. However, the estrogen effect was not completely removed by the addition of BGP to the multivariable models, and, therefore, other mechanisms for the effect of estrogen may also be important, such as an effect on calcium absorption and vitamin D metabolism (34) or calcitonin secretion (36,37). Estrogens have also been postulated to affect plasma phosphate (38), sensitivity of bone to parathyroid hormone (39), and other factors.…”

Section: Resultsmentioning

confidence: 99%

Sex steroids and bone mass. A study of changes about the time of menopause.

Slemenda¹,

Hui²,

Longcope³

et al. 1987

J. Clin. Invest.

327

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To examine the relationships between bone loss and sex steroids, 84 peri-and postmenopausal women were studied at 4-mo intervals for 3 yr. At each visit, measurements were made of bone mass at the midshaft and distal radius, of steroids, of gonadotropins, and of bone gla protein (BGP). Bone loss was -1% per yr among late perimenopausal and postmenopausal groups, whereas the early perimenopausal group lost no bone. Mean serum estrogen and BGP concentrations predicted rates of bone loss. BGP was negatively correlated with the rate of bone loss (r = -0.45) and with mean estrogen concentrations (r = -0.40). Multivariate regressions showed estrogen concentrations to be strong independent predictors of the slope of bone mass over time. When BGP concentrations were added to the models, the significance of estrogen was reduced, suggesting that a portion of the estrogen effect was mediated through effects on rates of bone remodelling.

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Calcitonin and the Calcium-Regulating Hormones in Postmenopausal Women: Effect of Oestrogens

Cited by 173 publications

References 19 publications

Calcitonin: From the Determination of Circulating Levels in Various Physiological and Pathological Conditions to the Demonstration of Lymphocyte Receptors

Calcitonin: From the Determination of Circulating Levels in Various Physiological and Pathological Conditions to the Demonstration of Lymphocyte Receptors

Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery

Sex steroids and bone mass. A study of changes about the time of menopause.

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