title: The impact of gonadal hormones on cannabinoid dependence.
abstract: Cannabis is the most widely used illicit substance in the United States. Women report greater positive subjective effects of cannabis, and greater cannabis withdrawal compared to men. Female rodents are more sensitive than males to some acute effects of Δ⁹-tetrahydrocannabinol (THC), and females also develop greater tolerance to THC in some assays. The purpose of this study was to determine whether gonadal hormones modulate THC dependence in rats. Adult rats were gonadectomized (GDX) or sham-GDX, and hormone was replaced in half of the GDX rats of each sex (testosterone in males; estradiol and/or progesterone in females). THC (30 mg/kg) or vehicle was administered twice daily for 6.5 days, followed on the seventh day by vehicle or rimonabant challenge and assessment for withdrawal-related behaviors. Sham-GDX females developed greater tolerance than males to THC-induced hypothermia, and GDX females given progesterone showed greater tolerance to THC-induced locomotor suppression. Rimonabant precipitated withdrawal, as evidenced by increased somatic signs (forepaw tremors, licking) and increased startle amplitude. Testosterone in GDX males decreased withdrawal-induced licking. Estradiol and progesterone in GDX females increased withdrawal-induced chewing, and progesterone increased withdrawal-induced sniffing. These results suggest that estradiol and progesterone may promote the development of dependence, whereas testosterone may protect against dependence. While the present study indicates that testosterone and estradiol produce opposite effects on THC-induced behavior, estradiol appears to play a broader role than testosterone in modulating THC's behavioral effects.
authors.affiliation: Center for Drug Discovery, RTI International.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Marusich
authors.affiliation: Department of Psychology, Washington State University.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Craft
authors.affiliation: Center for Drug Discovery, RTI International.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Lefever
authors.affiliation: Center for Drug Discovery, RTI International.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Wiley
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002369:Castration; D004195:Disease Models, Animal; D013759:Dronabinol / Q000633:toxicity; D004361:Drug Tolerance; D030762:Estrous Cycle / Q000187:drug effects; D005260:Female; D042341:Gonadal Hormones / Q000627:therapeutic use*; D020249:Hormone Replacement Therapy / Q000379:methods*; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000188:drug therapy*; D009043:Motor Activity / Q000187:drug effects; D010147:Pain Measurement / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013216:Reflex, Startle / Q000187:drug effects; D012727:Sex Characteristics; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy / Q000209:etiology; D013997:Time Factors
chemical_list: D042341:Gonadal Hormones; D013759:Dronabinol