Other Disorders Eye, Skin, Thyroid, etc

A number of investigators have examined plasma RBP concentrations and characteristics in patients with different varieties of retinitis pigmentosa. Normal 

Levels of RBP, TTR, and vitamin A were measured in 14 patients with hyperthyroidism and in 7 with hypothyroidism (Smith and Goodman, 1971). Both RBP and TTR levels were significantly lower than normal in hyperthyroid patients. In hypothyroid patients, plasma vitamin A was increased significantly RBP levels were somewhat higher than normal, but the difference was not statistically significant. In both hyper- and hypothyroidism, approximately normal molar ratios of RBP TTR and of RBP vitamin A were observed. The significance of these observations in thyroid disorders is not clear. 

In other endocrinological studies, women taking oral contraceptives have been found to have elevated plasma levels of both RBP and vitamin A (Vahlquist et al., 1979 Nonavinakere et al., 1981). The estrogen component seems to be largely responsible for these increased levels. The RBP level was also found to show a bicyclic variation during the menstrual cycle (Vahlquist et al., 1979). 

Levels of RBP have been measured in patients with infections of various kinds (Arroyave and Calcano, 1979), with bum injury (of between 2 and 37% of the body surface area) (Moody, 1982), and with stress arising from multiple traumas, cranial-cerebral lesions, or surgery (Kasper et al., 1975). Low RBP levels were found in all of these conditions. The RBP levels returned toward or to normal following recovery from infection or from the bum injury. 

Finally, relatively normal retinol and RBP levels were reported to be present in 91 children with hearing impairments of different etiologies (Biesalski et al., 1981). 

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