There are controversies about adverse effects of bisphenol A (BPA), a ubiquitous xenoestrogen, on reproduction and development of male animals. To understand BPA action and assess its risk more completely, we examined the impact of BPA at high doses on the testes of pubertal male Kunming (China) mice. BPA at 0 (control), 160, 480, and 960 mg/kg/day was given by gavage to mice from postnatal days (PND) 31-44, followed by observation of morphology and detection of apoptosis and expressions of Fas/FasL and active caspase-3 on PND 45, 60, and 90 by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling, immunohistochemistry, and Western blotting. There was no effect of BPA at 160 mg/kg/day, however, at 480 and 960 mg/kg/day there was underdevelopment of testes and disruption of spermatogenesis. There were many apoptotic Leydig and germ cells in the testes with apoptotic indices being significantly increased compared with controls. The expression of Fas and active caspase-3 was localized in the same cell types as apoptosis occurred, and expression levels of Fas, FasL, and active caspase-3 were significantly increased compared with controls. The disturbed spermatogenesis, apoptosis and upregulation of Fas, FasL, and active caspase-3 expression persisted to PND 90. The results suggest that high-dose BPA induces apoptosis of Leydig and germ cells in the mouse testis through the Fas-signaling pathway. Therefore, there is concern about reproductive health for humans occupationally exposed to high levels of BPA.

Analysis of global methylation in cells has revealed correlations between overall DNA methylation status and some biological states. Recent studies suggest that epigenetic regulation through DNA methylation could be responsible for neuroadaptations induced by addictive drugs. However, there is no investigation to determine global DNA methylation status following repeated exposure to addictive drugs. Using mice conditioned place preference (CPP) procedure, we measured global DNA methylation level in the nucleus accumbens (NAc) and the prefrontal cortex (PFC) associated with drug rewarding effects. We found that cocaine-, but not morphine- or food-CPP training decreased global DNA methylation in the PFC. Chronic treatment with methionine, a methyl donor, for 25 consecutive days prior to and during CPP training inhibited the establishment of cocaine, but not morphine or food CPP. We also found that both mRNA and protein level of DNMT (DNA methytransferase) 3b in the PFC were downregulated following the establishment of cocaine CPP, and the downregulation could be reversed by repeated administration of methionine. Our study indicates a crucial role of global PFC DNA hypomethylation in the rewarding effects of cocaine. Reversal of global DNA hypomethylation could significantly attenuate the rewarding effects induced by cocaine. Our results suggest that methionine may have become a potential therapeutic target to treat cocaine addiction.

In order to localize neuroendocrine gonadotropin-releasing hormone (GnRH) neurons in the monkey hypothalamus, four juvenile cynomolgus macaques (one female, three males) were each given two or three microinjections (0.2 to 0.3 pl per site) of the retrograde tracer wheat germ agglutinin-apoHorseradish peroxidase-10 nrn colloidal gold into the superficial, median eminence region of the infundibular stalk. Five to 15 days following surgery, the brains were fixed by perfusion and vibratomed at 40 pm in the frontal plane.Every 12th section was immunostained with rabbit anti-GnRH using the peroxidase anti-peroxidase technique with diaminobenzidine as the chromogen. Neuroendocrine GnRH neurons were easily identified in tissue sections as brown, imrnunostained cell bodies containing more than three distinct, dark blue, tracer-filled lysosomes. Neuronal counts from each complete series of sections were compiled by anatomical region, and the percentages of GnRH and neuroendocrine GnRH neurons determined.The highest proportion of neuroendocrine GnRH neurons (with projections to the median eminence) occurred in the ventral hypothalamic tract, especially in its medial third (71%), and in the supraoptic decussation just anterior to it. Proportions decreased moving laterally into the middle third (58%) and lateral third (25%) of the ventral hypothalamic tract. Further anterior and lateral, progressively smaller but significant neuroendocrine GnRH contributions were found in the supraoptic nucleus (57%) and lateral hypothalamus (33%), and in the medial preoptic area (26%). Although the medial preoptic area contained a greater percentage of the total GnRH-imrnunoreactive cell bodies (36%) than the ventral hypothalamic tract (27%), as a whole, the ventral hypothalamic tract contained 60% of the neuroendocrine GnRH neurons compared to only 25% from the medial preoptic area. Large numbers of GnRH cell bodies found in the diagonal band of Broca near the organum vasculosum of the lamina terrninalis were not retrogradely labeled. GnRH neurons were not observed in the arcuate nucleus, the few in the paraventricular nucleus were not neuroendocrine, and the contribution from the periventricular zone was negligible.Our results here are the first to identify the neurons giving rise to the neuroendocrine GnRH system in juvenile monkeys. The data indicate that more GnRH neurons close to the infundibulum serve a neuroendocrine (perhaps hypophysiotropic) role than do those in more anterior areas. Furthermore, they suggest that the ventral hypothalamic tract is the most important, and perhaps most influential, neuroendocrine GnRH cell group in primates. The data substantiate the observed autonomy of the medial basal hypothalamus in controlling gonadotropin secretion and menstrual cyclicity in these animals. However, they also infer that perhaps 60% of the GnRH neurons do not project to the primate median eminence, and thus may serve other non-neuroendocrine functions.Gonadotropin-releasing hormone (GnRH)-containing neurons in the forebr...

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Acute myeloid leukemia (AML) is a myeloid malignancy characterized by the proliferation of abnormal and immature myeloid blasts in the bone marrow. Circular RNA (circRNA) is a novel class of long non-coding RNA with a stable circular conformation that regulates various biological processes. The aberrant expression of circRNA and its impact on AML progression has been reported by a number of studies. Despite recent advances in circRNA research, our understanding of the leukemogenic mechanism of circRNA remains very limited, and translating the current circRNA-related research into clinical practice is challenging. This review provides an update on the functional roles of and research progress on circRNAs in AML with an emphasis on mechanistic insights. The challenges and opportunities associated with circRNA-based diagonostic and therapeutic development in AML are also outlined.