Effects of restraint on rat adrenomedullary response to 2-deoxy-D-glucose

Abstract

Male rats immobilized for 2 1/2 hours daily for seven or 40 consecutive days were compared to control animals. Urines were collected for two consecutive 24-hour intervals, starting with the beginning of the last 2 1/2-hour restraint interval. Four days after the last restraint interval, all rats received a single injection of 2-deoxy-D-glucose (2DG) (500 mg/kg). Immediately afterwards, urine specimens were collected for another 24-hour period. The 24-hour urinary epinephrine (E) of the initial period was markedly increased after seven immobilizations and 40 immobilizations. The increase in E was significant during the second day of collection after seven immobilizations, but not after 40 immobilizations. The urinary E during the period after 2DG administration was increased for all immobilized rats; the E levels after 40 immobilizations were greater than after seven immobilizations.

For evaluating adrenal changes, animals were immobilized daily and given 2DG daily. Six hours after one immobilization followed by 2DG there was a marked lowering of adrenal epinephrine and a small increase in adrenal tyrosine hydroxylase (TH) and phenylethanolamine-N-methyl transferase. Those animals immobilized and treated with 2DG daily for one week showed marked lowering of adrenal E and an increase in adrenal TH and dopamine-B-hydroxylase.