RELATIONSHIP OF VITAMIN B6 TO GLUCONEOGENIC ACTION OF CORTISOL11

Recent investigations have shown that cortisol administration results in a marked increase in liver glutamic-pyruvic transaminase enzyme activity. Because of this observation it has been suggested that gluconeogenic action of adrenal steroids may depend upon elevation of this transaminase level. Since pyridoxal phosphate is the cofactor for the enzyme, effects of cortisol on liver glycogen deposition and glutamic-pyruvic transaminase activity were studied in vitamin B6 deficient and control rats. The findings demonstrate that glucocorticoid action of cortisol is diminished in B6 depleted animals as is the effect of the hormone on transaminase activity. Other parameters of cortisol action such as involution of lymphoid tissue and inhibition of ACTH release were not altered by the vitamin deficiency. It is concluded that gluconeogenic activity of adrenal corticoids depends not only on their molecular configuration but also upon nutritional status of the animal. The findings also support the concept that glucocorticoid activity may depend on increased levels of liver glutamicpyruvic transaminase.