Immunohistochemical detection of estrogen receptor beta in alveolar bone cells of estradiol-treated female rats: possible direct action of estrogen on osteoclast life span

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structural and functional changes in the alveolar bone osteoclasts of estrogen-treated rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of combined hormonal and insulin therapy on the steroid hormone receptors and growth factors signalling in diabetic mice prostate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrastructural and proliferative features of the ventral lobe of the prostate in non-obese diabetic mice (NOD) following androgen and estrogen replacement associated to insulin therapy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Expression of fibroblast growth factor-8 and its cognate receptors, fibroblast growth factor receptor (FGFR)-3c and-4, in fetal bovine preantral follicles

Paracrine cell signaling is thought to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family have been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR-3c and FGFR-4) are expressed in bovine preantral follicles. Reverse transcription-polymerase chain reaction was used to amplify bovine FGF-8, FGFR-3c, and FGFR-4 from preantral follicle samples and a variety of fetal and adult tissues. All three genes were widely expressed in fetal tissues, with a restricted expression pattern in adult tissues. FGF-8 and FGFR-3c were expressed in secondary follicles in 70% of fetuses examined, whereas FGFR-4 expression was significantly less frequent (20%). FGFR-3c expression frequency was significantly lower in primordial compared to secondary follicles, and FGF-8 expression showed a similar trend. FGFR-4 was only observed when all follicle classes of an individual were expressing both FGF-8 and FGFR-3c. We conclude that FGF-8 and its receptors are expressed in preantral follicles in a developmentally regulated manner. (C) 2005 Wiley-Liss, Inc.

Use of knowledge regarding LH receptors to improve superstimulatory treatments in cattle

Embryo transfer is a biotechnology that has been used worldwide to increase the production of offspring from female bovines. Treatments to induce multiple ovulations (superovulation) have evolved from superstimulatory protocols that depended upon detection of oestrus to treatments that synchronise follicle growth and ovulation, allowing for improved donor management and fixed-timed AI (FTAI). The protocols associated with FTAI facilitate animal handling and produce at least as many viably embryos as conventional treatment protocols that required detection of oestrus. Recent knowledge regarding LH receptors (LHR) and follicular development can be applied to improve embryo transfer protocols. In fact, improvements in the superstimulatory treatment called the 'P-36 protocol', which include hormones that stimulate LHR, indicate that adjustments related to LHR availability may increase bovine embryo yield compared with conventional protocols based on the detection of oestrus.

Propolis Immunomodulatory Action In Vivo on Toll-Like Receptors 2 and 4 Expression and on Pro-Inflammatory Cytokines Production in Mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Morphological aspects of neuromuscular junctions and gene expression of nicotinic acetylcholine receptors (nAChRs) in skeletal muscle of rats with heart failure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Upregulation of muscarinic receptors by long-term nitric oxide inhibition in the rat ileum

1. The aim of the present study was to examine the effects of long-term nitric oxide (NO) blockade on contractions of the rat ileum induced by muscarinic agonists.2. Male Wistar rats received the NO synthesis inhibitor N (G) -nitro-l-arginine methyl ester (l-NAME; 20 mg/rat per day) in drinking water for 7, 15, 30 and 60 days. Concentration-responses curves to methacholine and carbachol were obtained and pEC(50) values were calculated. Saturation binding assays were performed in membranes prepared from rat ileum after 60 days of l-NAME treatment and the dissociation constant (K-D ) and maximal number of binding sites (B-max ) were determined by Scatchard analysis.3. The NO synthase activity of the ileum was markedly reduced in all l-NAME-treated groups. At 60 days after l-NAME treatment, a significant increase in the potency of methacholine (fourfold) and carbachol (threefold) was observed. In binding studies, we found a significant increase in B-max for [(3) H]-quinuclidinyl benzilate of approximately 57% in the l-NAME treated group without any significant change in K-D values. The contractile response to methacholine was not modified by the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (3 mumol/L). No morphological alterations in the rat ileum were observed in l-NAME-treated rats.4. Our findings suggest that treatment with l-NAME for 60 days induces a marked increase in the potency of methacholine and carbachol, as well as an increase in receptor number in the rat ileum.

Pulmonary receptors in reptiles: discharge patterns of receptor populations in snakes versus turtles

This study examines the effects of lung inflation/deflation with and without CO2 on the entire population of pulmonary receptors in the vagus nerve in two species of snakes and two species of turtles. We asked the question, how does the response of the entire mixed population of pulmonary stretch receptors (PSR) and intrapulmonary chemoreceptors (IPC) in species possessing both differ from that in species with only PSR? This was studied under conditions of artificial ventilation with the secondary goal of extending observations on the presence/absence of IPC to a further three species. Our results indirectly illustrate the presence of IPC in the Burmese python and South American rattlesnake but not the side necked turtle, adding support to the hypothesis that IPC first arose in diapsid reptiles. In both species of snake, CO2-sensitive discharge (presumably from IPC) predominated almost to the exclusion of CO2-insensitive discharge (presumably arising from PSR) while the opposite was true for both species of turtle. The data suggest that for animals breathing air under conditions of normal metabolism there is little to distinguish between the discharge profiles of the total population of receptors arising from the lungs in the different groups. Interestingly, however, under conditions of elevated environmental CO2 most volume-related feedback from the lungs is abolished in the two species of snakes, while under conditions of elevated metabolic CO2, it is estimated that volume feedback from the lungs would be enhanced in these same species.

Microscopic evaluation of proliferative disorders in the gerbil female prostate: Evidence of aging and the influence of multiple pregnancies

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exposure of young rats to high estrogen doses leads to degeneration of elongated spermatids

Single high doses of estrogen (35 mg/kg body weight) were administered to young rats aiming to exacerbate its effects on germ cell populations. The short-term (1 week) and medium-term (7 weeks) consequences of this estrogenic treatment (ET) on the testis were evaluated using light and electron microscopies, quantitative methods and TUNEL reaction. Short-term ET led to 50% atrophy of the testis, however, in the medium term the gonado-somatic index was recovered. No histopathological alterations were found at seminiferous epithelium except for short-term severe degeneration of elongated spermatids (EL) and low frequency of these cells in both time intervals. Two morphologically distinct patterns of degeneration were observed: (1) clusters of EL which were TUNEL-negative and exhibited bizarre appearance and nuclear fragmentation, (2) isolated apoptotic EL within the cytoplasm of Sertoli cells (SC). Both degenerative phenomena were more frequent in stages III - VIII of seminiferous cycle, whereas at stages I and II only coiling of flagellum was observed. One week after ET, small amounts of EL were detected in stages IX - XII, suggesting spermiation failure. Signs of functional SC damage such as an accumulation of myelin-like inclusions in their cytoplasm were observed in the short but not medium-term. However, the apoptotic rates still remained five times higher and the number of elongated spermatids was three-fold lower. Our data indicate that exposure to a high dose of estrogen around puberty has stage-specific effects on the testis and causes massive degeneration of elongated spermatids. (c) 2007 Elsevier Ltd. All rights reserved.