The effect of vitamin D on enzyme activities in the rat

Abstract

Histochemical methods offer the advantage, in the study of vitamin deficiency states, that a considerable amount of information can be obtained from each animal. The amount of tissue required for the demonstration of any one enzyme is small; thus the number of enzymes that can be examined is virtually unlimited.In this study a comparison was made of enzyme activities in tissues of normal and vitamin D-deficient rats. The tissues, other than bone, where lack of vitamin D is considered to have an effect, are those associated with calcium and phosphorus absorption and excretion and those associated with the control of calcium and phosphorus metabolism. The intestine and its associated glands, and the kidney and the parathyroid gland have therefore been selected for investigation. EXPERIMENTAL AnimalsThe rats were of the Lister Institute black and white stock maintained at Queen Elizabeth College. They were weaned at 23 days and taken for experiment at 28-30 days at weights ranging from 57 to 80 g. The histological procedure required pairs of animals for comparison, and limitation of time permitted only two or four animals to be dealt with in a week. Pairs of male rats were therefore taken for experiment at intervals, caged separately and fed on Steenbock's rachitogenic diet 2965 (Steenbock & Black, 1925) with or without a dose of vitamin D. Vitamin D was given as a solution of Adexolin (a concentrate of vitamins A and D ; Glaxo Research Ltd) in arachis oil in a single weekly dose of 10 i.u. vitamin D. The animals without vitamin D received arachis oil to compensate for any effect of the inclusion of the small amount of oil in the diet. The diet was offered as a dry powder and was made once or twice weekly. It consisted of freshly ground whole yellow maize complete with the germ 76%, wheat gluten 20%, calcium carbonate 3 yo, and sodium chloride I %, with a Ca:P ratio of 4:'.At the beginning of the experiment 'line tests' (Bills, Honeywell, Wirick & Nussmeier, 1931) were made on the right radius and ulna of every rat on the day it was killed. The left radius and ulna were put into the deep freeze and examined all at the same time at the end of the experiment. The femur, tibia and fibula from all rats were kept in the deep freeze until the end of the experiment so that all bone ash determinations could be done at the same time. Bone ash was measured by the method of 10-2

Interrelationship and Effects of Calcium and Vitamin D on Growth, Feed Efficiency and Bone Ash of Weanling Rats

“…This indicates that the requirement for vitamin D is very smail in a diet in which the proportion of calcium: phosphorus is in normal range and in adequate amount. These results are in agreement with the results of Irving (7) Chesman et al (3) and Gaster et al (5).…”

“…Growth ,was improved by the addition of vitamin D to this diet, but no effeet was obscrved on bone ash content. Cheesman and others (3) showed that the rats recciving vitamin D on rachitogenie diet gained more had more ash than the rats reeeiving no vitamin D.…”

Studies of the action of vitamin D in the rat

“…The animals were then killed and tissues for histochemical examination and analysis of bone ash were prepared as described previously (Cheesman et al 1964(Cheesman et al , 1966.…”

“…In rats killed 3 days after a dose of vitamin D there was a marked increase in serum Ca and P but a less clear change in bone Ca and P although epiphyseal calcification was evident. The parathyroid activity was less than in rats dosed throughout the experiment.In previous studies of the effect of vitamin D on enzyme activities in the rat (Cheesman, Copping & Prebble, 1964, 1966, changes were observed after 1-7 weeks' deprivation and after I week of recovery. The leucine aminopeptidase activity of the parathyroids appeared to be the most sensitive index of the vitamin D status of the animal.…”

“…In previous studies of the effect of vitamin D on enzyme activities in the rat (Cheesman, Copping & Prebble, 1964, 1966, changes were observed after 1-7 weeks' deprivation and after I week of recovery. The leucine aminopeptidase activity of the parathyroids appeared to be the most sensitive index of the vitamin D status of the animal.…”