Pituitary-adrenal response to ketamine
Kudo, M.; Kudo, T.; Matsuki, A.
Masui. Japanese Journal of Anesthesiology 40(7): 1107-1112
1991
ISSN/ISBN: 0021-4892 PMID: 1656113 Document Number: 372347
Fahringer and coworkers have shown the possibility that the steroid response to ketamine is not caused by a direct action on the adrenal gland and is dependent on the presence of a functioning pituitary gland. To clarify these points, we examined the effects of ketamine on ACTH production in isolated pituitary cells of rats. Corticosterone and aldosterone production was measured in isolated adrenal cells of rats to test the possibility of a direct influence of ketamine on the adrenal gland. Rat anterior pituitary and adrenal glands cells respectively were obtained by enzymatic digestion of intact glands collected from Wistar rats. This cell pellet was suspended in Hank's buffer containing 0.1% BSA and distributed to plastic tubes. The cell samples were preincubated for 90 min in a 37 degrees C waterbath under an atmosphere of 5% CO2/95% O2. Ketamine was then added to normal and to ACTH treated cells, which were incubated for 4 hr, and centrifuged. Samples of the supernatant liquid were taken, and aldosterone and ACTH were measured by radioimmunoassay. Corticosterone was determined by a fluorimetric method. Ten individual measurements were made for each sample. Results are expressed as mean +/- s.e. Statistical analysis was performed using Student's t-test. The results indicated that ketamine significantly increased ACTH secretion in the isolated pituitary cells. On the other hand, ketamine had no significant effects on adrenal corticosterone formation. There were similar effects by ketamine on ACTH-induced corticosterone production when compared with that obtained by ACTH alone.