Ascorbic acid pituitary

The adrenal glands and pituitary glands have the highest tissue concentration of ascorbic acid. The brain, Hver, and spleen, however, represent the largest contribution to the body pool. Plasma and leukocyte ascorbic acid levels decrease with increasing age (152). Elderly people require higher ascorbic acid intakes than children to reach the same plasma and tissue concentration (153). 

Ascorbic acid is photosensitive and unstable in aqueous solution at room temperature. During storage of foods, vitamin C is inactivated by oxygen. This process is accelerated by heat and the presence of catalysts. Ascorbic acid concentration in human organs is highest in adrenal and pituitary glands, eye lens, liver, spleen, and brain. Potatoes, citrus fruits, blade currants, sea buckthorns, acerola, rose hips, and red paprika peppers are among the most valuable vitamin C sources [1,2]. 

Glemboiski, C. C. (1986), The characterization of the ascorbic acid-mediated a-amidation of a-melanottopin in cultuiod intermediate pituitary lobe cells. Endocrihaldgy US, 1461-1468. 

Different concentrations in compartments that can exchange ascorbic acid may also be achieved by nonlinear transfers such as active transport processes. Nonlinearity, however, cannot be determined by experimental designs using only one steady state level. The brain, adrenals, pituitary gland, and eyes take up ascorbic acid by an energy-dependent active transport mechanism (30,31). 

The oxidative product of ascorbic acid, dehydroascorbic acid, is the preferred form of the vitamin for uptake by neutrophils, erythrocytes, and lymphocytes (27). Once within the erythrocyte, dehydroascorbic acid is reduced to ascorbic acid by a glutathione-dependent, dehydro-ascorbic-acid-reducing enzyme (20,28). However, the reduced form of ascorbic acid is found in most other tissues, that is, liver, lungs, kidneys, skin, and pituitary and adrenal glands (20,29). From these studies, ascorbic acid is taken up by several tissues by an energy-dependent and Na -sensitive process, but the transport of the oxidized vitamin form follows the principles of diflFusion. 

R19. Rosemberg, E., Solod, E. A., and Albert, A., Luteinising hormone activity of human pituitary gonadotropin as determined by the ventral prostate weight and the ovarian ascorbic acid depletion methods of assay. J. Clin. Endocrinol. Melab. 24, 714-728 (1964). 

Schaus, R., The ascorbic acid content of human pituitary cerebral cortex, heart, and skeletal muscle and its relation to age. Am. /. Clin. Nutrition 5, 39-41 (1957). 

Pituitary extracts contain some basic protein which may interfere with heparin. Although ACTH and heparin have similar effects on endocrine weight, body weight, protein metabolism, lipid metabolism, sludged blood, anaphylaxis, dispersibility phenomena, and peripheral eosinophilia , heparin prevents the eosinopenia and lymphopenia due to ACTH and corti-sone . It has no effect on the depletion of adrenal ascorbic acid by ACTH, sodium salicylate, adrenaline or histamine, or by cold exposure . In contrast, protamine blocks the depletion of adrenal ascorbic acid by ACTH. 

Recently it has been proposed (Eisenstein and Shank, 1951 Pirani, 1952) that scurvy itself is just another nonspecific stress. The changes seen in the adrenals in this disease can then be simply explained on the assumption of cortical stimulation by the anterior pituitary. The dietary deficiency of ascorbic acid is thus no longer necessary to explain the reduction of ascorbic acid in the cortexl A more interesting question than Is scurvy a stress is Does stress precipitate scurvy The answer is certainly, yes. 

Obviously the greatest interest now centers on stress situations. Under some conditions kno to deplete ascorbic acid in the adrenal cortex of animals there is also evidence of an increased catabolism of the vitamin in man. After bums and fractures (Andreae and Browne, 1946) and also in active rheumatoid arthritis (Hall d al., 1939) the level of reduced ascorbic acid in the plasma has been found to be low, requiring unusually large doses to raise it. Apparently the vitamin is used up with abnormal speed in these conditions, thou the mechanism involved is obscure. It is difficult to believe that it is all destroyed in the adrenal cortex under the influence of ACTH discharged from the anterior pituitary, because the amount in the cortex at any one moment is infinitesimal (Section III, 2) compared with the amount that may appear to be lost from the body. According to Sayers et al. (1946), ACTH does not deplete other organs of ascorbic acid, at least in the rat and guinea pig. Perhaps the vitamin is not really destroyed, but merely shifted over to the oxidized form (DHA). 

The pituitary gland distinguishes itself by having a rather high content of ascorbic acid. The only systematic study on the variation with age in... 

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