Objective: To examine the regulatory aspects of zinc-a2-glycoprotein (ZAG) association with obesityrelated insulin resistance. Methods: ZAG mRNA and protein were analyzed in subcutaneous adipose tissue (AT) and circulation of lean, obese, prediabetic, and type 2 diabetic men; both subcutaneous and visceral AT were explored in lean and extremely obese. Clinical and ex vivo findings were corroborated by results of in vitro ZAG silencing experiment. Results: Subcutaneous AT ZAG was reduced in obesity, with a trend to further decrease with prediabetes and type 2 diabetes. ZAG was 3.3-fold higher in subcutaneous than in visceral AT of lean individuals. All differences were lost in extreme obesity. Obesity-associated changes in AT were not paralleled by alterations of circulating ZAG. Subcutaneous AT ZAG correlated with adiposity, adipocyte hypertrophy, whole-body and AT insulin sensitivity, mitochondrial content, expression of GLUT4, PGC1a, and adiponectin. Subcutaneous AT ZAG and adipocyte size were the only predictors of insulin sensitivity, independent on age and BMI. Silencing ZAG resulted in reduced adiponectin, IRS1, GLUT4, and PGC1a gene expression in primary human adipocytes. Conclusions: ZAG in subcutaneous, but not in visceral AT, was markedly reduced in obesity. Clinical, cellular, and molecular evidence indicate that ZAG plays an important role in modulating whole-body and AT insulin sensitivity.

The situation following anti-obesity drug termination is rarely investigated, eventhough a decrease in body weight needs to be sustained. Therefore, this study examined the impact of twice-daily peripheral administration of 5 mg/kg [N-palm-γGlu-Lys] prolactin-releasing peptide 31 (palm-PrRP31) in mice with diet-induced obesity (DIO from consuming a high-fat diet) after 28 days of treatment (palm-PrRP31 group) and after 14 days of peptide treatment followed by 14 days of discontinuation (palm-PrRP31 + saline group). At the end of the treatment, cumulative food intake, body weight and subcutaneous fat weight/body weight ratio and leptin plasma level were reduced significantly in both the palm-PrRP31 group and the palm-PrRP31 + saline group compared to the saline control group. This reduction correlated with significantly increased FOSB, a marker of long-term neuronal potentiation, in the nucleus arcuatus and nucleus tractus solitarii, areas known to be affected by the anorexigenic effect of palm-PrRP31. Moreover, activation of leptin-related hypothalamic signaling was registered through an increase in phosphoinositide-3-kinase, increased phosphorylation of protein kinase B (PKB, AKT) and enhanced extracellular signal-regulated kinase 1/2 phosphorylation. Besides, lowered apoptotic markers c-JUN N-terminal kinase and c-JUN phosphorylation were registered in the hypothalami of both palm-PrRP31-treated groups. This study demonstrates that palm-PrRP31 positively affects feeding and leptin-related hypothalamic signaling, not only after 28 days of treatment but even 14 days after the termination of a 14-day long treatment without the yo-yo effect.

Clozapine (CLZ) stimulates several brain areas some of them being sensitive to stress. Aim of the present study was to reveal whether 7-day CLZ administration may: (1) activate the selected forebrain areas; (2) modulate response of these structures to a single forced swimming episode (FSW); (3) modulate response of these structures to FSW after 13-day preconditioning with mild unpredictable stress complex (CMS). Used groups of male Wistar rats: (a) vehicle or CLZ treated for 7 days; (b) vehicle or CLZ treated for 7 days and on the 7th day exposed to FSW; (c) CMS exposed for 13 days, from the 8th day injected with vehicle or CLZ and on the 14th day exposed to FSW. Vehicle or CLZ (10 mg kg day in 0.1% acetic acid) were administered intraperitoneally. c-Fos quantification was performed 90 min after FSW in the medial prefrontal cortex (mPFC), dorsolateral (dLS) and ventrolateral (vLS) septum, dorsolateral (DLStr) and dorsomedial (DMStr) striatum, nucleus accumbens shell (NAc shell) and core (NAc core), and hypothalamic paraventricular nucleus (PVN). In unstressed animals CLZ increased c-Fos expression in the mPFC, vLS, and PVN. After a single FSW, CLZ decreased the number of c-Fos immunoreactive cells in the vLS, DMStr, NAc shell, and NAc core. In CMS rats, CLZ suppressed c-Fos immunoreactivity in response to FSW in the PVN. Our data indicate that CLZ elicits different impact on neuronal activities in the brain areas studied and modifies the response of these structures to stress. CLZ effect seems to be affected by stress duration.