Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/11953
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Type: Journal article
Title: Oestrogen deficiency impairs intestinal calcium absorption in the rat
Author: O'Loughlin, P.
Morris, H.
Citation: The Journal of Physiology, 1998; 511(1):313-322
Publisher: WILEY
Issue Date: 1998
ISSN: 0022-3751
1469-7793
Abstract: 1. The effects of ovariectomy on the relationships between calcium consumption and calcium balance and its components were assessed in adult (10-14 months) sham-operated and ovariectomized (Ovx) rats fed a semi-synthetic diet with the calcium content varying between 0.02 and 0.4%. 2. Adaptation to dietary calcium restriction was monitored for 47 days from commencement of a 0.02 % Ca diet. 3. Response to 1,25-dihydroxyvitamin D (20 ng kg-1 day-1) administration in sham and Ovx rats and oestradiol (E2) (20 microgram kg-1 day-1) replacement in Ovx rats was assessed in rats fed a 0.05% Ca diet. 4. Ovx rats had lower intercepts for the relationships between calcium consumption and both calcium balance (P < 0.005) and intestinal calcium absorption (P < 0.005) compared with sham rats, but 1,25-dihydroxyvitamin D was not reduced in Ovx rats. 5. The magnitude of adaptation to dietary calcium restriction was unaffected by ovariectomy. 6. Intestinal calcium absorption was stimulated by an equivalent amount in sham and Ovx rats following 1, 25-dihydroxyvitamin D administration, although this did not reach statistical significance for sham (sham, t = 1.91, n.s.; Ovx, t = 3. 18, P < 0.05). 7. Oestradiol replacement in Ovx rats induced a marked increase in intestinal calcium absorption (t = 8.25, P < 0. 005), without stimulating circulating 1,25-dihydroxyvitamin D levels and led to a marked increase in calcium balance (t = 6.89, P < 0. 005). 8. These data indicate that the impairment of intestinal calcium absorption following ovariectomy is not the result of reduced circulating 1,25-dihydroxyvitamin D or reduced intestinal responsiveness to 1,25-dihydroxyvitamin D. Moreover E2 stimulates intestinal calcium absorption probably by a direct effect on the intestine.
Keywords: Animals
Rats
Rats, Sprague-Dawley
Calcium, Dietary
Calcium
Calcitriol
Estradiol
Estrogens
Estrogen Replacement Therapy
Ovariectomy
Intestinal Absorption
Kinetics
Time Factors
Female
DOI: 10.1111/j.1469-7793.1998.313bi.x
Appears in Collections:Aurora harvest 7
Physiology publications

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