Acute THC Altered Adrenal Catecholamine Stores Without a Matching Enzyme Decline
An experimental THC study found lower adrenal-medullary catecholamine stores after acute exposure without a statistically significant decline in a key synthesis enzyme. The changes disappeared with repeated treatment, while circulating hormones followed partly different patterns.
Tissue content and enzyme activity were separate measures
Acute THC decreased adrenal norepinephrine and epinephrine content and increased their ratio, mainly at the higher tested dose. Tyrosine hydroxylase activity did not show a statistically significant decrease. Reduced stored transmitter therefore did not establish a corresponding reduction in measured synthesis capacity.
Repeated exposure changed the result
The tissue-content effects disappeared after seven or fourteen days of daily treatment, suggesting tolerance on these endpoints. That finding does not establish tolerance to every stress response. Stored catecholamine content is also different from measuring secretion during a stressful event.
Plasma hormones did not move together
ACTH and corticosterone changes did not parallel adrenal-medullary findings. Acute prolactin changes were statistically correlated with catecholamine depletion, but correlation did not establish mediation. The authors considered both pituitary-related and direct adrenal explanations; the supplied abstract does not settle between them.
This study illustrates why tissue stores, enzyme activity and plasma hormone concentrations should remain distinct. It does not establish a human stress-response test, endocrine diagnosis or clinical treatment. The truncated supplied abstract supports the reported comparisons without justifying additional unreported details.
Related: interpreting cannabis tolerance claims.
Research cited
Rodríguez de Fonseca F; Fernández-Ruiz JJ; Murphy L; Eldridge JC; Steger RW; Bartke A. Effects of delta-9-tetrahydrocannabinol exposure on adrenal medullary function: evidence of an acute effect and development of tolerance in chronic treatments. Pharmacology, biochemistry, and behavior (1991). doi:10.1016/0091-3057(91)90368-c. Findings discussed from the study abstract.
