Expression of functional melanocortin-4 receptor in the hypothalamic GT1-1 cell line.

Mutations in the melanocortin-4 receptor (MC4-R) cause obesity in both mice and humans, and the receptor is presumed to have an important role in the regulation of energy homeostasis. The MC4-R is expressed in discrete sets of neurons in the central nervous system, and thus it has been technically difficult to study the regulation of expression and the signaling mechanisms of this receptor. We report here a neuronal cell line that exhibits endogenous functional expression for the MC4-R. Initially, RT-PCR analysis showed the presence of MC4-R RNA in the hypothalamic GT1-1 and GT1-7 cells. In addition, GT1-7 cells expressed melanocortin-3 receptor while the GT1-1 subclone specifically expressed predominantly the MC4-R RNA. High-affinity binding sites were demonstrated in the GT1-1 and GT1-7 cells for NDP-alpha melanocyte-stimulating hormone (MSH; K(i) = 1.1 x 10(-10) and 1.8 x 10(-10) M) and agouti-related protein (AGRP; K(i) = 1.548 x 10(-9) and 1.663(-9) M). alpha-MSH-stimulated cAMP production in GT1-1 cells with an EC(50) of 2.2 x 10(-8) M, and cAMP production was inhibited in the presence of AGRP, an endogenous antagonist of the MC4-R. Stimulation of gonadotropin-releasing hormone (GnRH) secretion was achieved with 1 nM to 1 microM concentrations of NDP-alpha-MSH while no GnRH secretion was observed when the GT1-1 cells were treated with AGRP. The data presented here show that GT1-1 cells specifically express a functional MC4-R that couples to GnRH release.

Luteal phase sertraline treatment for premenstrual dysphoric disorder. Results of a double-blind, placebo-controlled, crossover study.

OBJECTIVE: To test the efficacy of late-luteal phase dosing of sertraline hydrochloride in women with moderate-to-severe premenstrual dysphoric disorder. This highly prevalent disorder often causes significant psychosocial impairment. DESIGN: Double-blind, crossover trial of each 2-menstrual cycle of baseline, sertraline treatment, and placebo. Randomization to sertraline treatment vs placebo occurred after a 2-cycle, drug-free period. SETTING: A large outpatient multispecialty clinic in central Texas. PATIENTS: Fifty-seven women aged 19 to 49 years with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of premenstrual dysphoric disorder. INTERVENTIONS: Late-luteal phase treatment with sertraline hydrochloride in daily doses of 50 mg (cycle 1) followed by 100 mg (cycle 2) vs placebo. MAIN OUTCOME MEASURES: The 22-item calendar of premenstrual experiences was completed daily and constituted the primary outcome measure, consisting of a total score and behavioral and physical factor scores. RESULTS: A repeated-measures analysis of variance for crossover designs found a significant beneficial effect from sertraline treatment in improving the calendar of premenstrual experiences total (P < .01), behavioral factor (P < .01), and physical factor (P < .04) scores. Most women improved when taking sertraline, 50 mg, although a dose increase to 100 mg yielded further improvement in approximately 25% of women. Use of sertraline was extremely well tolerated; the only adverse event reported by 10% or more of women was insomnia in 8 (14%) of them. CONCLUSIONS: Luteal phase treatment with sertraline was a safe and effective treatment for moderate-to-severe premenstrual dysphoric disorder. Further controlled studies are needed to confirm the results of this preliminary study.