This experiment determined the amount of leptin required to correct different abnormalities in leptin-deficient ob/ob mice. Baseline food intakes and body weights lean (+/?) obese (ob/ob) C57B1/6J <ob> mice were recorded for 7 days. An Alzet miniosmotic pump was placed peritoneal cavity each mouse delivered 0, 1, 2, 5, 10, or 42 microg/day human In mice, 2 microg leptin/day reduced intake weight, increased hypothalamic brain stem serotonin concentrations. All fat pads 35-40% by 10...

Although dependent on the integrity of a central pacemaker in suprachiasmatic nucleus hypothalamus (SCN), endogenous daily (circadian) rhythms are expressed wide variety peripheral organs. The pathways by which controls periphery unclear. Here, we used parabiosis between intact and SCN-lesioned mice to show that nonneural (behavioral or bloodborne) signals adequate maintain circadian clock gene expression liver kidney, but not heart, spleen, skeletal muscle. These results indicate SCN...

A precise understanding of neural circuits controlling lipid mobilization and thermogenesis remains to be determined. We have been studying the sympathetic nervous system (SNS) contributions white adipose tissue (WAT) lipolysis largely in Siberian hamsters. Central melanocortins are implicated control outflow WAT, and, moreover, melanocortin 4 receptors (MC4-R) appear principally involved. previously found that acute third ventricular melanotan II (MTII; an MC3/4-R agonist) injections...

Acute release of corticotropin-releasing factor (CRF) during repeated restraint (3-h on each 3 days) causes temporary hypophagia but chronic suppression body weight in rats. Here we demonstrated that a second bout caused additional loss, continuing daily for 10 days did not increase loss because the rats adapted to stress. In these two studies serum leptin, which suppresses endocrine response stress, was reduced restrained Peripheral infusion leptin before and prevent stress-induced although...

Energy balance results from the coordination of multiple pathways affecting energy expenditure and food intake. Candidate neuropeptides involved in are melanocortins. Several species, including Siberian hamsters studied here, decrease increase intake response to stimulation blockade melanocortin 4-receptor (MC4-R). In addition, central application MC3/4-R agonist melanotan-II decreases body fat (increases lipolysis) beyond that accounted for by its ability Because an sympathetic nervous...

We previously reported that rats exposed to repeated restraint (3 h/day for 3 days) experience temporary hypophagia and a sustained reduction in body weight compared with nonrestrained controls. Studies described here determined the involvement of central corticotropin-releasing factor (CRF) receptors initiation this chronic response acute stress. In experiment 1, Sprague-Dawley were fitted cannulas lateral ventricle infused 50 μg αhCRF-(9—41) or saline immediately before on each days...

Inhibition of fatty acid oxidation stimulates feeding behavior in rats. To determine whether a decrease hepatic triggers this behavioral response, we compared the effects different doses methyl palmoxirate (MP), an inhibitor oxidation, on food intake with those vivo and vitro liver muscle metabolism. Administration 1 mg/kg MP selectively decreased but did not stimulate intake. In contrast, increased rats given 5 or 10 MP, which inhibited to same extent as low dose addition suppressed...

Leptin has been shown to reduce body fat in vivo. Adipocytes express the leptin receptor; therefore, it is realistic expect a direct effect of on adipocyte growth and metabolism. In vitro studies examining metabolism require supraphysiological doses protein see decrease lipogenesis or stimulation lipolysis, implying an indirect action leptin. It also possible that reduces adipose mass by inhibiting preadipocyte proliferation (increase cell number) and/or differentiation (lipid filling). Thus...

Surgical removal of the epididymal white adipose tissue (EWAT) depot (lipectomy; EWATx) in laboratory rats or mice decreases spermatogenesis, but this phenomenal finding has not been investigated depth. Specifically, detailed histology, neuroendocrine profiles, copulatory behavior, lipectomy other WAT depots, rescue by autologous EWAT transplants, tests whether EWATx effect is due to disruption testes innervation occurring during have performed. Therefore, first study, we performed male...

The purpose of this study was to assess the effects voluntary wheel running on expression leptin mRNA in rats that are either sensitive (OM) or resistant (S5B/P1) diet-induced obesity. Male OM and S5B/P1 had ad libitum access standard rodent diet water. At 3–5 weeks age, animals both strains were randomly assigned an exercise sedentary control group. groups 24-h a wheel, they trained for 7 weeks. During 1–4, progressively increased their running. 5–7, exercisers tended run more than did (∼60...

Leptin preserves lean tissue but decreases adipose by increasing lipolysis and/or inhibiting lipogenesis. The sympathetic nervous system (SNS) is a primary regulator of lipolysis, it not known if leptin increases norepinephrine turnover (NETO) in white tissue. In this study, we examined the effect administered either as chronic physiological dose (40 microg/day for 4 days from ip miniosmotic pumps) or an acute injection third ventricle (1.5 microg injected two times daily 2 days) on NETO and...

It has been suggested that high-fat (HF) diet exaggerates the stress-induced release of glucocorticoids due to activation hypothalamic-pituitary-adrenal (HPA) axis. In an initial experiment, in which rats were fed HF for 4 days, we found HF-fed controls stopped gaining weight, indicating they hyperresponsive mild stress tail bleeding but responded same as low-fat (LF)-fed more severe restraint. A second experiment confirmed these results when a days showed exaggerated corticosterone response...

Leptin increases sympathetic nervous system (SNS) activity in brown adipose tissue and renal nerves. Experiments described here tested whether SNS innervation is required for peripheral, physiological concentrations of leptin to reduce body fat. In experiment 1, one epididymal (EPI) fat pad was sympathectomized by local injection 6-hydroxydopamine (6OHDA) C57BL/6 mice that were then infused 13 days with PBS or 10 microg leptin/day from an intraperitoneal miniosmotic pump. Surprisingly, EPI...