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The regulation of the Glucocorticoid Receptor (GR) transcript was investigated in the gills of Atlantic salmon (Salmo salar) during the parr-smolt transformation. Sampling of parr and smolt fish was performed between December and July and in particular during the smoltification period occurring in spring. Quantification of GR transcripts revealed differences between the two groups in March and at the beginning of April. During these dates, the amounts of GR mRNA in parr gills were respectively three and two fold lower than those measured in smolts. In order to determine which factors are responsible for these differences, we studied the long-term effects of prolactin and Cortisol treatments on GR transcript in the gills of presmolt fish. The plasma levels of these two hormones respectively drop and rise during smoltification. Contrary to Cortisol long-term treatment which did not modify the amount of gill GR transcript, short-term treatment induced a significant decrease within 12 hours. Prolactin long-term treatment caused a significant increase of GR transcript abundance after 13 days of implant treatment. This result is unexpected with regard to those obtained in the smoltification analysis but is in agreement with previous studies performed in mammary gland revealing a positive control of PRL on GR in epithelial cells. Our data suggest that the regulation of the GR transcript during the parr-smolt transformation probably involves several hormonal factors.

The distribution of the glucocorticoid receptor (GR)within the forebrain of rainbow trout has been studied by means of in situ hybridization (ISH) and immunohistochemistry (ICC) using probes and antibodies directed against the AB-domain of the rainbow trout GR (rtGR). Both rtGR mRNA and protein exhibited the same pattern of distribution. A strong labelling was observed in all subdivisions of the preoptic nucleus, in the thalamic region and in the mediobasal hypothalamus (nucleus recessus lateralis, nucleus lateralis tuberis).It was notably found that all magnocellular neurons of the nucleus preopticus pars magnocellularis (NPOmc) were positive with both ISH and ICC. Furthermore, numerous cells of the anterior lobe of the pituitary were positively stained. Double staining studies allowed to identify part of the rtGR expressing cells. At the telencephalic level, it was found that GnRH neurons frequently express rtGR in vitellogenic females. Virtually all tyrosine hydroxylase (TH) cells in the anteroventral part of the preoptic nucleus (NPOav) were rtGR-positive. In this same area, a colocalization between rainbow trout estradiol receptor (rtER) and TH has already been documented, indirectly demonstrating that rtER and rtGR are colocalized. The same holds true for the GTH-II cells of the anterior pituitary which express both types of receptors. These results provide information on the potential sites of cortisol action on the reproductive axis directly at the pituitary level or indirectly on neuroendocrine Systems controllingGTH-II secretion, possibly via GR-ER interactions.

In conflicts between primate groups, the resource-holding potential ( RHP) of competitors is frequently related to group size or male group size, which can remain relatively constant for long periods of time, promoting stable intergroup dominance relationships. Demographic changes in neighboring groups, however, could introduce uncertainty into existing relationships. Among tufted capuchin monkeys ( Cebus apella nigritus), dominant male replacement is a relatively infrequent demographic event that can have a profound effect on both the composition and size of the social group. Here, we report such a case and the consequences for home range use and intergroup aggression. Between June 2008 and August 2010, we periodically followed two neighboring groups (Macuco and Rita) in Iguazú National Park, recording daily paths ( N = 143) and encounters between the groups ( N = 28). We describe the events leading to a change in the male dominance hierarchy in the larger group (Macuco), which resulted in the death or dispersal of all adult males, followed by the succession of a young adult male to the dominant position. This takeover event reduced the numerical advantage in number of males between the two groups, although the ratio of total group sizes remained nearly constant. Following this shift in numerical asymmetry, the degree of escalation of intergroup aggression increased, and we observed reversals in the former intergroup dominance relationship. These changes in behavior during intergroup encounters were associated with changes in the use of overlapping areas. In the 6 months following the takeover, the area of home range overlap doubled, and the formerly dominant group's area of exclusive access was reduced by half. These results suggest that RHPin tufted capuchin monkeys is related to male group size. Furthermore, they highlight the importance of considering rare demographic events in attempts to understand the dynamics of aggression between primate groups. Am. J. Primatol. 74:804-810, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Transforming acidic coiled-coil (TACC) proteins are hypothesized to play a role in normal cellular growth and differentiation and to be involved in centrosomal microtubule stabilization. Our current studies aim to delineate the expression pattern of TACC3 protein during cellular differentiation and in a variety of normal human tissues. TACC3 is known to be upregulated in differentiating erythroid progenitor cells following treatment with erythropoietin and is required for replication of hematopoietic stem cells. However, we demonstrate that a dramatic upregulation of TACC3 also occurs during the early differentiation of NIH 3T3-L1 cells into adipocytes and PC12 cells into neurons, indicating that TACC3 mediates cellular differentiation in several cell types. Using real-time PCR, we quantitated the mRNA levels of TACC3 compared to TACC1 and TACC2 in various human adult tissues. We observed the highest expression of TACC3 mRNA in testis, spleen, thymus and peripheral blood leukocytes, all tissues undergoing high rates of differentiation, and a lower level of expression in ovary, prostate, pancreas, colon, small intestine, liver and kidney. In contrast, TACC1 and TACC2 mRNA levels are more widespread. By immunohistochemistry, we confirm that the TACC3 protein localizes to differentiating cell types, including spermatocytes, oocytes, epithelial cells, bone marrow cells and lymphocytes. Thus, these observations are concordant with a basic role for TACC3 during early stages of differentiation in normal tissues. [Copyright &y& Elsevier]