AJP - Endocrinology and Metabolism, Vol 251, Issue 4 400-E406, Copyright © 1986 by American Physiological Society

ARTICLES

Bone changes due to pregnancy and lactation: influence of vitamin D status

P. J. Marie, L. Cancela, N. Le Boulch and L. Miravet

The effects of pregnancy and lactation on endosteal bone formation and resorption were evaluated in vitamin D-depleted (-D) and vitamin D-repleted (+D) rats. Pregnancy induced a marked stimulation of osteoclastic bone resorption and of static and dynamic parameters of bone formation and mineralization. Bone resorption increased independently of vitamin D status and did not correlate with plasma 1,25-dihydroxyvitamin D3 [1,25(OH)2D] levels, but it was associated with increased plasma immunoreactive parathyroid hormone (iPTH) concentrations. Stimulation of the endosteal bone formation rate was mainly impaired in D-depleted rats, resulting in trabecular bone loss, which, in -D mother rats, was associated with decreased bone ash and total bone calcium. Lactation further stimulated bone resorption and reduced the trabecular bone volume; ash weight and bone calcium content were also decreased independently of the vitamin D status and changes in plasma iPTH levels. In presence of vitamin D, the bone formation rate increased fourfold during lactation but was unchanged in -D lactating rats. During lactation, vitamin D-depleted rats lost twofold more calcified bone than +D rats because of impaired mineralization. Thus, the present study shows that both the endosteal bone resorption and formation are stimulated by pregnancy and lactation and that vitamin D is required for normal bone mineralization during the reproductive period.

This article has been cited by other articles:

				E. G. Vajda, B. M. Bowman, and S. C. Miller Cancellous and Cortical Bone Mechanical Properties and Tissue Dynamics During Pregnancy, Lactation, and Postlactation in the Rat Biol Reprod, September 1, 2001; 65(3): 689 - 695. [Abstract] [Full Text] [PDF]