Effects of Glucocorticoids Upon Adrenal and Urinary Epinephrine and Norepinephrine and the Activity of Enzyme Phenylethanolamine-N-methyltransferase in Rats Made Partially Deficient in Vitamin D: Role of Vitamin D Supplementation

Abstract

Influence of individual and combined administration of hydrocortisone and vitamin D upon adrenal and urinary catecholamines in vitamin D deprived rats has been studied. One month of vitamin D free diet resulted in 49% increase in adrenal norepinephrine and 22% decrease in Phenylethanolamine-N-Methyltransferase (PNMT) activity whereas epinephrine remained unaffected from the value of normally fed rats. Daily administration of vitamin D for 11 days did not abolish adrenal norepinephrine increase but partially restored PNMT activity. Hydrocortisone treatment produced increases in adrenal epinephrine and PNMT activity. Combined treatment with hydrocortisone and vitamin D reversed the effects of individual treatment.

One month of vitamin D free diet decreased urinary excretion of both norepinephrine and epinephrine by 24% and 77% respectively compared to standard diet values. Daily administration of vitamin D restored to normal level the urinary excretion of epinephrine and norepinephrine in one month vitamin D deprived rats. Four injections of hydrocortisone modified epinephrine and norepinephrine urinary excretion to normal value, but theses effects were totally reversed after 9 days of treatment. The combined administration of vitamin D and hydrocortisone for 11 days totally restored both urinary monoamines. From these results it can be gathered that presence of vitamin D is a permissive factor for the glucocorticoids to exert their effects on adrenal monoamine storage and excretion.

Key words

Epinephrine - Norepinephrine - Adrenal - Vitamin D - PNMT - Hydrocortisone - Monoamine Urinary Excretion - Diet