International journal of molecular medicine
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Neuropeptide-B (NPB) and neuropeptide-W (NPW) are recently discovered endogenous ligands of the GPR7- and GPR8-receptors (R), which in humans are expressed in the hypothalamus and probably involved in the regulation of energy homeostasis and neuroendocrine axes. GPR8-Rs are absent in rodents, where the GPR8-like-R has been described. Reverse transcription-polymerase chain reaction detected the expression of NPB, NPW, GPR7-R and GPR8-like-R mRNAs in rat adrenocortical cells (both freshly-dispersed and 4-day-cultured cells). ⋯ Both NPB and NPW enhanced ACTH-stimulated aldosterone secretion and did not affect either basal or ACTH-stimulated corticosterone production by dispersed zona fasciculata/reticularis (ZF/R) cells. The prolonged (4-day) exposure to NPW, but not NPB, raised corticosterone secretion from cultured ZF/R cells, and both neuropeptides increased the proliferation rate of cultured cells. Taken together, our findings indicate that NPB and NPW affect rat adrenocortical function, so they may be included in that large family of peptides involved in the autocrine-paracrine stimulation of secretion and growth of adrenal cortex.
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The aim of this study was to evaluate the morphometric changes of adipose tissue of lean and obese rats as assessed by computerized image analysis (IA) system in experimental conditions, with different degrees of adiposity. Moreover, to validate measures obtained by image analysis by correlation with direct measures of adiposity (body weight, epididimal fat, mean fat cell size and serum leptin). Finally to correlate these changes to expression of genes involved in lipid deposition and mobilization in adipose tissue. ⋯ Distribution of measures for each sample, an index of spread of adipose tissue texture, as expressed by the standard deviation, correlated with adiposity (standard deviation vs epididimal fat depot: p=0.002) thus suggesting that adipose tissue texture increases its heterogeneity when adiposity is lower. This observation is in agreement with the hypothesis that the process of lipid mobilization from adipose tissue is not uniform, but a subpopulation of slimming adipocytes undergoes a complete release of their fat content while the rest of the tissue is much less affected. Moreover, image analysis system seems a reliable quantitative tool for assessment of adipose tissue texture.