Effect of acute intravenous administration of delta-9-tetrahydrocannabinol on the episodic secretion of immunoassayable growth hormone in the rat

Endocannabinoids and the Endocrine System in Health and Disease

Some of the earliest reports of the effects of cannabis consumption on humans were related to endocrine system changes. In this review, the effects of cannabinoids and the role of the CB1 cannabinoid receptor in the regulation of the following endocrine systems are discussed: the hypothalamic-pituitary-gonadal axis, prolactin and oxytocin, thyroid hormone and growth hormone, and the hypothalamic-pituitary-adrenal axis. Preclinical and human study results are presented.

The effects of prenatally administered endogenous cannabinoid on rat offspring

We reported previously that the main psychoactive component of marihuana, delta9 tetrahydrocannabinol (THC), when injected prenatally, temporarily inhibited the developing hypothalamo-pituitary system in rat offspring. In the present study, we investigated the effects of the recently described endogenous ligand for the central cannabinoid receptor, arachidonyl-ethanolamide (anandamide, ANA), on the postnatal development of the hypothalamo-pituitary axis (HPA) when administered during the third week of gestation. Rat pups were killed every fifth day from delivery to the 20th postnatal day; gonads, pituitary, and rest of body were weighed, and samples were collected for analysis of gonadotropin releasing hormone in the hypothalamus and luteinizing hormone, follicle stimulating hormone, prolactin, and growth hormone in the pituitaries and sera. The effects of ANA and THC were compared. Both ANA and THC caused predominantly inhibitory effects on the measured parameters. The inhibition was most pronounced immediately following delivery, whereas at the end of the investigated period (20th postnatal day) no differences were observed. We conclude that endogenous and exogenous cannabinoids have similar but slightly different effects on the developing HPA and that the action is transitory. We postulate that ANA probably acts via central cannabinoid receptors and/or neuroendocrine receptors to function as a neuromodulator.

Effects of anandamide (endogen cannabinoid) on anterior pituitary hormone secretion in adult ovariectomized rats

It has been shown that the main psychoactive component of marihuana, delta 9-tetrahydrocannabinol (THC) has mainly inhibitory effects on pituitary luteinizing hormone (LH), prolactin (PRL) and growth hormone (GH) and has no or little effect on follicle stimulating hormone (FSH) secretion. Recently the purification and availability of the putative endogenous ligand for the cannabinoid receptor, anandamide (arachidonyl ethanol-amide, anandamide) (ANA) provided us the opportunity to compare the effects of THC and ANA on the female neuroendocrine system in ovariectomized (OVX) rats. OVX was performed three weeks prior to the experimental period to avoid cyclic differences. OVX rats were injected i.p. with either THC or ANA (0.02 mg/kg.b.w./day, respectively) or vehicle for two weeks. The results show that both ANA and THC decrease serum LH level although THC with a higher degree. No significant differences were observed in serum FSH level. Both drugs decreased serum PRL. Serum GH was increased after THC administration and significantly decreased after ANA. The results indicate that ANA and THC alter pituitary hormone secretion, mainly by inhibitory action. The site of action requires further investigations.