Abstract

Injecting epinephrine into normal fasted rats depressed the serum concentrations of α-aminoisobutyric acid (AIB) and 1-aminocyclopentanecarboxylic acid (ACPC) and simultaneously increased the levels of these model amino acids in liver and heart within 2 hr. The levels of the two compounds in skeletal muscle and diaphragm were unchanged, but the distribution ratios in these tissues were increased because the serum levels decreased. Epinephrine showed a smaller effect at ½ hr.

Injecting the epinephrine antagonist dihydroergotamine methanesulfonate simultaneously with epinephrine removed three-fourths of the increase produced by the hormone in the absolute level and distribution ratio of ACPC in liver, and one-half of the increase in heart. In the presence of the inhibitor, epinephrine was one-third less effective in depressing the serum ACPC level. Neither adrenalectomy nor hypophysectomy greatly diminished the epinephrine-stimulated ACPC transfer into the four tissues examined. The results suggest that the elevated tissue levels found after epinephrine injection are not caused to any large extent by endogenous adrenocortical or hypophyseal hormones, or by insulin.