The central cannabinoid receptor inactivation suppresses endocrine reproductive functions

The function of central cannabinoid (CB1) receptor was investigated in the regulation of the pituitary-gonad axis in CB1 receptor knockout male mouse. Serum luteinizing hormone (LH) and testosterone (T) levels and basal T sec retion in vitro of testes were significantly decreased in mutant (CB1-/-) m ice. The receptor agonist, anandamide (ANA), suppressed LH and T secretion in wild type (CB1+/+) mice but had no effect in receptor inactivated animal s. The results are the first descriptions indicating the direct action of C B, receptors on LH and T secretion and the immunohistological demonstration of CB1 receptors in the Leydig cells. The results also indicate that CB1 r eceptors are responsible for the effects of exogenous cannabinoids on repro ductive functions. (C) 2001 Academic Press.