title: Effects of i.c.v. administration of leptin on copulatory and ingestive behavior in STZ-induced diabetic male rats.
abstract: It is well known that circulating leptin concentrations correlate with adiposity in both humans and rodents and decrease after fasting, energy restriction, or weight loss. The goal of the present study was to confirm whether the decreases of copulatory behavior and the increases of ingestive behavior in STZ-induced diabetic male rats could be reversed by i.c.v. administration of leptin. Adult male Wistar-Imamichi rats aged 9 weeks were used for the studies. Males received a single injection of STZ (60 mg/kg, i.p.) and vehicle. During the experiment, individual body weight, and food and water intake were measured. The copulatory and ingestive behaviors in STZ-induced diabetic males were observed at 2 and 4 weeks after STZ. At 6 weeks after STZ, leptin (10 microg/10 microl) or aCSF (artificial cerebrospinal fluid) was injected through a lateral ventricle cannula and the above two behaviors were observed again. The i.c.v. leptin injection to STZ-induced diabetic males resulted in a significant increase of ejaculation frequencies (3.6 +/- 0.26 vs. 2.9 +/- 0.30 times) and a significant decrease in amount of food ingested (36.2 +/- 1.93 vs. 23.2 +/- 3.76 g), compared with the aCSF-injected control (p<0.01). These findings suggest that the copulatory and ingestive behaviors in i.c.v. leptin-injected STZ diabetic males were restored to levels equivalent to those in control males.
authors.affiliation: Behavioral Neuroscience Laboratory, Graduate School of Veterinary Medicine, Nippon Veterinary and Animal Science University, Tokyo, Japan.
authors.forename: Toru R
authors.initials: TR
authors.lastname: Saito
authors.forename: Takayuki
authors.initials: T
authors.lastname: Tatsuno
authors.forename: Akira
authors.initials: A
authors.lastname: Takeda
authors.forename: Haruo
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Suzuki
authors.forename: Misao
authors.initials: M
authors.lastname: Terada
authors.forename: Shinobu
authors.initials: S
authors.lastname: Aoki-Komori
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.forename: Lajos
authors.initials: L
authors.lastname: Koranyi
authors.forename: Gyorgy M
authors.initials: GM
authors.lastname: Nagy
mesh_terms: D000818:Animals; D003307:Copulation / Q000187:drug effects*; D003921:Diabetes Mellitus, Experimental / Q000523:psychology*; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D007276:Injections, Intraventricular; D020738:Leptin / Q000008:administration & dosage* / Q000494:pharmacology* / Q000502:physiology; D008297:Male; D051381:Rats; D013311:Streptozocin
chemical_list: D020738:Leptin; D013311:Streptozocin