EFFECTS OF ANANDAMIDE ON GESTATION IN PREGNANT RATS

The present study was to test whether the recently described endogenou s ligand for the cannabinoid receptor; arachidonyl-ethanolamide (anand amide, ANA), may produce similar effects on pregnancy as the main psyc hoactive component of marihuana: Delta(9)-tetrahydrocannabinol (THC) i n rats. ANA, THC (0.02mg/kg i.p./day, respectively) or vehicle were in jected daily over the third week of pregnancy. The pregnant rats were either killed on day 21 of pregnancy or followed up to delivery. Resul ts show a significant increase in the duration of pregnancy after both THC and ANA treatment. Both drugs caused an increase in the frequency of stillbirths. The mothers' hormone contents in tissues and sera wer e measured. Decreased LH content was observed in the serum of treated animals. No changes in FSH content were observed either in the pituita ry or in the sera Pituitary prolactin (PRL) levels was lower in ANA tr eated animals as compared both to controls or THC treated subjects. Th e serum PRL, content decreased in all experimental groups. Decrease in serum progesterone was more prominent in treated rats, Serum levels o f prostaglandins (PGF 1 alpha and PGF 2 alpha) were significantly decr eased after THC and ANA treatment. We conclude that ANA has the same t endency to change reproductory parameters in pregnant rats as THC, alt hough in some cases the effects of ANA were slightly different from th at of THC. Both endogenous and exogenous cannabinoids inhibit PG synth esis in pregnant rats and this maybe responsible for the delay constit ute the mechanism in the onset of labour.