Effect of estrogen in relation to dietary vitamin D3 and calcium on activity of intestinal alkaline phosphatase and Ca-ATPase in immature chicks.
The interaction between 17 beta-estradiol (E2), vitamin D3 (D3), and dietary Ca on the activities of Ca-ATPase and alkaline phosphatase (AP) was determined in the intestine of young female chicks. Chicks (n = 36) were assigned to two groups, one of which was transferred to a low Ca (0.2%) diet and the other maintained on a regular diet. One week later, each group was further divided into three subgroups and given daily injections of 0(oil), 0.25, or 0.5 mg E2/kg body wt for 14 days. E2 treatment as well as low dietary Ca significantly increased AP activity (P < 0.05), whereas the highest E2 dose decreased jejunal Ca-ATPase (P < 0.05). In a separate study, day-old chicks (n = 40) fed a purified diet supplemented with or without D3 for 24 days were divided into two subgroups and administered daily injections of either 0 or 0.25 mg estrogen 3-benzoate/kg body wt for 5 days. E2 alone or in combination with D3 failed to change Ca-ATPase activity in either the duodenum or the jejunum. However, E2 enhanced the D3-stimulated AP activity measured in the supernatant of duodenum (D3, P < 0.001; E2, P > 0.05; E2 x D3, P < 0.05) and jejunum (D3, P < 0.001; E2, P > 0.05; E2 x D3, P = 0.06). Daily injections of 0.5 mg E2/kg body wt for 6 days to 6-week-old D3-adequate chicks (n = 16) significantly increased AP activity in jejunum but not in liver and kidney (P < 0.05). In conclusion, E2 treatment enhanced the activity of intestinal AP but not Ca-ATPase. This enhancement was independent of dietary Ca, but was D3-dependent and tissue specific. The results suggest that the pubertal increase in plasma E2 can affect Ca absorption from the intestine by increasing the activity of AP.
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West Virginia University, Division of Animal and Veterinary Science, Morgantown 26506-6108.
Klandorf
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D000375:Aging / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D000818:Animals; D001835:Body Weight; D002136:Calcium, Dietary / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D002762:Cholecalciferol / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007279:Injections, Subcutaneous; D007422:Intestines / Q000201:enzymology*
D002136:Calcium, Dietary; D002762:Cholecalciferol; D004958:Estradiol; D000469:Alkaline Phosphatase; D000252:Calcium-Transporting ATPases