Δ-9-Tetrahydrocannabinol Suppression of Episodic Luteinizing Hormone Secretion in the Ovariectomized Rat*

Induction of Luteinizing Hormone Release by Electrochemical Stimulation of the Medial Preoptic Area in Δ⁹-Tetrahydrocannabinol-Blocked Proestrous Rats

“…Earlier reports that exogenous LHRH induces an LH surge in THC-blocked proestrous rats [3] and overcomes the THC-induced LH suppression in ovariectomized rats [28], together with similar findings from other species (I, 25). strongly suggest that THC alters LH secretion through cen tral action reducing the release of LHRH into the hypophy sial portal circulation.…”

“…These results are consistent with the hypothesis that THC inhibits gonadotropin secretion by action within the central nervous system, but demonstrate that the central inhibitory effect of THC' does not prevent the release of LH-releasing hormone (LHRH) when the LHRH neurosecretory units are activated by brain stimulation. Thus, the antiovulatory effect of THC appears to result from .an inhibition of LH secretion which does not involve the direct blockade of LHRH release.Inhibition of luteinizing hormone (LH) secretion by AMetrahydrocannabinol (THC), the predominant psy choactive constituent of marijuana [20j, occurs under a var iety of physiological circumstances in man and experimental animals [3,6,8,18,28,29]. In sexually mature cycling females, THC inhibits the preovulatory surge of LH secre tion through action at a site and by a mechanism which remains unclear [1,2,22].…”

“…In sexually mature cycling females, THC inhibits the preovulatory surge of LH secre tion through action at a site and by a mechanism which remains unclear [1,2,22]. However, since THC does not directly inhibit basal or stimulated LH release from pituitary cells in vitro [7,24], and since the administration of exoge nous LH-releasing hormone (LHRH) readily provokes an LH surge during THC-induced suppression of LH secretion [1,3,25,28], asuprapituitary locus forTHC action is indicat ed. Consistent with that indication are reports that the THCinduced inhibition of LH release is associated with changes in the uptake and turnover of hypothalamic neurotransmit ters which may be involved in the release of LHRH [4,15,26] and that the hypothalamic concentration of L.HRII is in creased following acute THC treatment [19].…”

Effects of Delta-9-Tetrahydrocannabinol, Cannabinol and Cannabidiol, Alone and in Combinations, on Luteinizing Hormone and Prolactin Release and on Hypothalamic Neurotransmitters in the Male Rat

“…In the rat, THC administration reduces LH release in intact [1] and castrated males [2] and recently, was shown to suppress the pulsatile pat tern of LH secretion in castrated testosterone-treated animals [3], Moreover, the tonic circulating level of PRL in the intact male is acutely suppressed following THC administration [4,5], The inhibitory effects ofTHC on LH and PRL secretion appear to result from a central drug action since THC is ineffective in suppressing basal or stimulated LH and PRL release from pitu itary cells in vitro [6][7][8], and since LH-releasing hormone (LHRH) stimulation or administration of exogenous thyrotro pin-releasing hormone readily provokes LH or PRL secretion, respectively, during THC-induced suppression of hormone re lease [9][10][11]. The recent findings that intracerebroventricular THC administration suppresses LH and PRL secretion in the male rat further substantiate a central nervous system site of Received: August 18, 1989 Accepted after revision: March 6, 1990 THC action [12,13].…”

Novel Aspects of Glucocorticoids Actions on Energy Homeostasis and Hydromineral Balance

“…However, over the past few years, the number of studies investigating the participation of CB1R in several areas has increased dramatically. Pioneer studies revealed that the exogenous administration of "cannabis-like" compounds inhibits the activity of diverse neuroendocrine functions (Lomax, 1970;Rettori et al, 1990;Tyrey, 1978). Accordingly, it has been demonstrated that the mRNA for the CB1R is expressed in the hypothalamus and in the external layer of the median eminence of rodents (Herkenham et al, 1991;Wittmann et al, 2007), as well as in both the anterior and intermediate lobes of the human pituitary gland (Pagotto et al, 2001).…”