Role of prolactin in vitamin D metabolism and calcium absorption during lactation in the rat

1982 ◽  
Vol 94 (3) ◽  
pp. 443-453 ◽  
Author(s):  
C. J. Robinson ◽  
E. Spanos ◽  
M. F. James ◽  
J. W. Pike ◽  
M. R. Haussler ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Parathyroid Hormone ◽  
Alkaline Phosphatase Activity ◽  
Plasma Levels ◽  
Calcium Absorption ◽  
High Plasma ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolism

Intestinal calcium absorption and plasma levels of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) were measured in lactating and non-lactating rats and the effects of bromocriptine and exogenous prolactin treatment were evaluated. In lactating rats calcium absorption and plasma levels of parathyroid hormone, 1,25(OH)2D3 and alkaline phosphatase activity were significantly increased. Bromocriptine treatment significantly reduced the enhanced calcium absorption and levels of plasma 1,25(OH)2D3 and alkaline phosphatase but had no significant effect on plasma levels of parathyroid hormone. Prolactin administered with bromocriptine to lactating animals prevented all the changes observed with bromocriptine treatment alone. It was concluded that the increased plasma levels of prolactin during lactation lead to high plasma levels of 1,25(OH)2D3 which are responsible for the enhanced intestinal calcium absorption.

Role of intestinal calcium absorption in plasma calcium regulation of the rat

1984 ◽  
Vol 246 (5) ◽  
pp. R680-R683 ◽  
Author(s):  
F. Bronner
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Calcium Intake ◽  
Calcium Absorption ◽  
Calcium Regulation ◽  
Plasma Calcium ◽  
Intestinal Calcium Absorption ◽  
High Calcium Intake ◽  
High Calcium

Transmural calcium movement in the intestine involves both saturable and nonsaturable components, with the saturable movement subject to regulation by vitamin D and indirectly by parathyroid hormone. Under conditions of high-calcium intake, calcium absorption due to the saturable component is minimized and the numerical value of the nonsaturable component can equal that found in vitamin D-deficient or parathyroidectomized (PTX) animals on similar calcium intakes. Yet in PTX animals intestinal calcium represents a larger proportion of the calcium inflow into the central pool, and PTX animals are less able to regulate their plasma calcium than hormonally intact animals. This demonstrates that intestinal calcium input in the rat can be classified as a signal disturbing (raising) the plasma calcium.

Intestinal Calcium Absorption and Vitamin D Metabolism

1982 ◽  
Vol 4 (1) ◽  
pp. 75???86
Author(s):  
Milton M. Weiser ◽  
John H. Bloor ◽  
Amita Dasmahapatra
Keyword(s):  
Vitamin D ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolism

THE ROLE OF THE THYROID IN THE INTESTINAL EFFECT OF VITAMIN D ON RACHITIC RATS

1970 ◽  
Vol 48 (4) ◽  
pp. 541-544 ◽  
Author(s):  
M. WINTER ◽  
E. MORAVA ◽  
G. SIMON
Keyword(s):  
Vitamin D ◽  
Intestinal Absorption ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Thyroid Glands ◽  
And Control

SUMMARY The effect of 20 i.u. vitamin D3 on the intestinal absorption of calcium was investigated in thyroidectomized and control rachitic rats. Vitamin D3 increased both duodenal and jejunal calcium absorption in the absence of the thyroid glands. These results suggest that neither thyroxine nor calcitonin are necessary for the effect of vitamin D3 on intestinal calcium absorption.

Effect of age on intestinal calcium absorption and adaptation to dietary calcium.

1979 ◽  
Vol 236 (6) ◽  
pp. E769 ◽  
Author(s):  
H J Armbrecht ◽  
T V Zenser ◽  
M E Bruns ◽  
B B Davis
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Active Transport ◽  
Alkaline Phosphatase Activity ◽  
Calcium Absorption ◽  
Intestinal Adaptation ◽  
Dietary Calcium ◽  
Intestinal Calcium Absorption ◽  
Calcium Diet ◽  
Low Calcium

To study the reported decline in intestinal calcium absorption with age, calcium active transport, immunoreactive calcium protein (CaBP) content, and alkaline phosphatase activity were measured in the intestine of two strains of rats aged 3-wk--20 mo. Calcium active transport, as measured by everted gut sacs from Sprague-Dawley rats, was greatest at 3 wk, but it declined rapidly with no active transport demonstrable at 3 mo or thereafter. CaBP content closely paralleled the decline in active transport, but alkaline phosphatase activity increased as active transport decreased. Intestinal adaptation to dietary calcium was studied by feeding high- and low-calcium diets to Fischer 344 rats aged 1.5--12 mo. In 1.5-mo-old rats fed a low-calcium diet, there was an increase in calcium active transport, CaBP content, and alkaline phosphatase activity relative to animals fed a high-calcium diet. However, the magnitude of this intestinal adaptation decreased with age until there was only marginal adaptation by 12 mo. The observed changes in calcium active transport with age and diet may be explained by the parallel changes in the vitamin D-dependent CaBP content of the intestine.

Intestinal Calcium Absorption and Vitamin D Metabolism

1982 ◽  
Vol 4 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Milton M. Weiser ◽  
John H. Bloor ◽  
Amita Dasmahapatra
Keyword(s):  
Vitamin D ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolism

Bone Mineral Homeostasis in Spontaneously Diabetic BB Rats. I. Abnormal Vitamin D Metabolism and Impaired Active Intestinal Calcium Absorption*

Endocrinology ◽  
1989 ◽  
Vol 124 (2) ◽  
pp. 565-572 ◽  
Author(s):  
BULANGU L. NYOMBA ◽  
JOHAN VERHAEGHE ◽  
MONIQUE THOMASSET ◽  
WILLY LISSENS ◽  
ROGER BOUILLON
Keyword(s):  
Vitamin D ◽  
Bone Mineral ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolism ◽  
Mineral Homeostasis ◽  
Bb Rats
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