The role of corticosteroids in the homeostasis of the eye.
Three problems were studied on the human and rabbit eye: to what extent the mineralocorticoids contribute to the control of Na+ and K+ transport in the lens epithelium, how do the glucocorticoids influence the concentration of glucose in the aqueous humour and what is the effect of the pituitary-adrenal axis on the hemato-ocular barrier. Specific receptor-like proteins binding aldosterone were found in the lens epithelium. Na+ and K+ concentrations in the aqueous were influenced by both aldosterone and spironolactone administration. The aldosterone concentration in human cataracts was found to be higher in cases of cataracts complicated by arterial hypertension. In spite of some indication of anticataractogenous action of mineralocorticoids, aldosterone did not prevent the formation of cortisol-induced cataract in chick embryos. Glucose concentration in the aqueous was increased by glucocorticoid administration as well as by stimulation of their secretion by ACTH. Further, the contribution of the pituitary-adrenal axis to the breakdown of the hemato-ocular barrier was investigated by measuring the changes of the total protein content in the aqueous. ACTH1-24 caused a partial breakdown of the barrier, as well as ACTH4-10 or alpha-MSH. As the latter two peptides lack the stimulative effect on the corticoid secretion and glucocorticoids themselves fail to increase the protein content in the aqueous, the breakdown of the hemato-ocular barrier seems to be essential for ACTH-linked peptide fragments and is not mediated by corticoids.
D000305:Adrenal Cortex Hormones / Q000378:metabolism / Q000494:pharmacology*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002386:Cataract / Q000139:chemically induced; D005123:Eye / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects*; D006801:Humans; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism
D000305:Adrenal Cortex Hormones; D010446:Peptide Fragments; D000450:Aldosterone; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D012964:Sodium; D005947:Glucose; D011188:Potassium