Effects of gestational exposure to di-n-butyl phthalate and mineral oil on testis development of the Mongolian gerbil.

Phthalate esters are endocrine disrupters that can affect the development of the testis in a species-specific manner. However, their interference in the male gonads of the Mongolian gerbil is unknown. The aim of the present study was to evaluate whether gestational exposure to di-n-butyl phthalate (DBP) interferes with the development of the gerbil testis during the first six weeks of life. Males were evaluated at 1, 7, 14, 28, 35 and 42 days of age in an untreated (control) group or groups exposed from 8 to 23 days gestation to DBP (100mgkg-1day-1 in mineral oil) or vehicle by maternal gavage. DBP exposure impaired cell proliferation within the seminiferous cords at birth, but increased proliferation at the end of the first week, when higher testosterone concentrations were observed. The vehicle (mineral oil) reduced the total number of gonocytes and attenuated the decrease in testosterone concentrations at 7 days. The vehicle also altered gonocyte relocation at 14 days and increased oestrogen concentrations at 28 days by approximately 112%. In summary, both DBP and oil interfered in gonadal development and testosterone plasma concentrations in the first week of postnatal life. However, the changes observed at the beginning of puberty were not seen after exposure to DBP, indicating a more harmful effect of mineral oil in this period.

Morphological and histological characters of penile organization in eleven species of molossid bats.

The penis is the reproductive organ that ensures efficient copulation and success of internal fertilization in all species of mammals, with special challenges for bats, where copulation can occur during flight. Comparative anatomical analyses of different species of bats can contribute to a better understanding of morphological diversity of this organ, concerning organization and function. In this study, we describe the external morphology and histomorphology of the penis and baculum in eleven species of molossid bats. The present study showed that penile organization in these species displayed the basic vascular mammalian pattern and had a similar pattern concerning the presence of the tissues constituting the penis, exhibiting three types of erectile tissue (the corpus cavernosum, accessory cavernous tissue, and corpus spongiosum) around the urethra. However, certain features varied among the species, demonstrating that most species are distinguishable by glans and baculum morphology and glans histological organization. Major variations in glans morphology were genus-specific, and the greatest similarities were shared by Eumops species and N. laticaudatus. The greatest interspecific similarities occurred between M. molossus and M. rufus and between Eumops species. Save for M. molossus and M. rufus, morphology of the baculum was species-specific; and in E. perotis, it did not occur in all specimens, indicating that it is probably under selection. In the histological organization, the most evident differences were number of septa and localization of the corpora cavernosa. In species with a baculum (Molossus, Eumops and Nyctinomops species), the corpora cavernosa predominantly occupied the dorsal region of the penile glans and is associated with the proximal (basal) portion of the baculum. In species that do not have a baculum (Cynomops, Molossops and Neoplatymops species), the corpora cavernosa predominantly occupied the ventro-lateral region of the glans.

Melatonin intake since weaning ameliorates steroidogenic function and sperm motility of streptozotocin-induced diabetic rats.

Melatonin may be used as an antioxidant in therapy against systemic sequelae caused by oxidative stress in diabetes. However, as melatonin has a major role in regulating reproductive activity, its consequence on reproductive parameters under diabetes needs to be better clarified. We have studied whether prior and concomitant treatment of juvenile Wistar rats with low doses of melatonin interferes in reproductive damage induced by experimental diabetes after 1 and 8 weeks. The consequences of melatonin administration since weaning on reproductive parameters of healthy rats at adulthood were also evaluated. Melatonin was provided in drinking water (10 µg/kg b.w./day) after weaning (5-week-old). Diabetes was induced by streptozotocin injection (4.5 mg/100 g b.w.) at 13-week-old rats, and rats were euthanized 1 and 8 weeks after disease onset. Diabetes decreased circulating testosterone levels (~35% to 1 week; ~62% to 2 months; p < 0.01) but did not affect testes sperm counts. Two months of diabetes reduced the sperm reserve and led to atrophy of epididymal cauda. Both 1-week and 2-month diabetes impaired sperm motility, decreased the number of spermatozoa with progressive movement, and increased the number of immotile sperm. Melatonin intake reduced serum testosterone levels ~29% in healthy 14-week-old and ~23% in 21-week-old rats and reduced daily testicular sperm production ~26% in the latter disease stage, but did not interfere in sperm reserves and transit time for both experimental periods. Exogenous melatonin prevented the serum testosterone decrease and damage to sperm motility in diabetic rats and attenuated reduction in sperm counts and transit time induced by 1-week diabetes but did not avoid this decrease at 2-month diabetes. Low doses of melatonin administered prior to and during experimental diabetes attenuated damage to testicular steroidogenic activity and preserved sperm motility, but not sperm reserves in the rat. Our data indicated a differential action of melatonin in normoglycemic and hyperglycemic conditions, particularly in sperm motility and testosterone production by Leydig cells.

Microscopic evidence of the opportunistic reproductive strategy and early sexual maturation of the small-sized characin Knodus moenkhausii (Characidae, Pisces).

We investigated the reproductive biology of Knodus moenkhausii, an abundant small-sized characin fish with broad occurrence in the Paraná River basin, Brazil. Specimens were collected monthly to determine fecundity, length at first maturity, reproductive period and spawning type. Gonads were macroscopically classified according to their form, size and texture in three different stages (immature, maturing or mature). Histological procedures were conducted to confirm gonadal developmental stages, and it was possible to notice that maturing females actually presented atretic oocytes, and all males that were macroscopically classified as immature, maturing and mature actually presented abundant spermatozoa in their gonads. Because of these discrepancies, a reclassification of gonadal maturations stages was needed after histological analysis, reinforcing its importance to studies on the reproduction of small characins. Reproduction occurred throughout the year though with two peaks. The length of the smallest mature individuals was 13 mm SL for males and 24 mm SL for females. Despite presenting relatively small batch fecundity, some life history traits such as early reproduction, multiple spawning throughout the year, in association with known opportunistic feeding habits, explain the high abundance of this species in locations where it occurs.

Effects of maternal diabetes on male offspring: high cell proliferation and increased activity of MMP-2 in the ventral prostate.

This study presents a comprehensive view of the histological and functional status of the prostate of adult rat offspring of mothers subjected to gestational diabetes induced by alloxan. The ventral prostate of male adult offspring of diabetic (DP) or normal (CP) mothers was evaluated for collagen fibres, cell death, fibroblasts, smooth muscle cells, cell proliferation, matrix metalloproteinases (MMPs), androgen receptors (AR), transforming growth factor ß1 (TGFß-1), catalase and total antioxidant activity. The prostates of DP animals were lower in weight than those of the CP group. The DP group also exhibited hyperglycaemia and hypotestosteronemia, higher cell proliferation and AR expression, a reduction in α-actin (possibly interfering with the reproductive function of the prostate), and enhanced activity of MMP-2, although the absolute content of MMP-2 was lower in this group. These findings were associated with increased TGFß-1 and decreased collagen distribution. The prostates of DP rats additionally exhibited reductions in catalase and total antioxidant activity. Thus, rats developing in a diabetic intrauterine environment have glycaemic and hormonal changes that impact on the structure and physiology of the prostate in adulthood. The increased AR expression possibly leads to elevated cell proliferation. Stromal remodelling was characterized by enhanced activity of MMP-2 and collagen degradation, even with increased TGFß-1 activation. These changes associated with increased oxidative stress might interfere with tissue architecture and glandular homeostasis.

AKT and AMPK activation after high-fat and high-glucose in vitro treatment of prostate epithelial cells.

Considering the increasing consumption of saturated fat and glucose in diets worldwide and its possible association to carcinogenesis, this investigation analysed the proliferation profile of nonmalignant human prostate epithelial cells after exposure to elevated levels of fat and glucose. PNT1A cells were cultured with palmitate (100 or 200 µM) and/or glucose (450 mg/dl) for 24 or 48 h. Treated cells were evaluated for viability test and cell proliferation (MTS assay). AKT and AMPK phosphorylation status were analysed by Western blotting. After 24 h of high-fat alone or associated with high-glucose treatment, there was an increase in AMPK and AKT activation associated to unchanged MTS-cell proliferation. Following 48 h of high-fat but not high-glucose alone, cells decreased AMPK activation and maintained elevated AKT levels. These data were associated to increased cell proliferation after further high-fat treatment. After longer high-fat exposure, MTS revealed that cells remained proliferating. High-glucose alone or associated to high-fat treatment was not able to increase cell proliferation and AKT activation. A high-fat medium containing 100 µM of palmitate stimulates proliferation in PNT1A cells by decreasing the activation of AMPK and increasing activation of AKT after longer exposure time. These findings improve the knowledge about the negative effect of high levels of this saturated fatty acid on proliferative disorders of prostate.

Cyclosporin A causes impairment of the ventral prostate tissue structure of Wistar rats.

Cyclosporin A (CsA) is an immunosuppressive drug widely used in medicine to reduce the immune system activity and, therefore, the risk of organ rejection after transplantation. However, many side effects can be related to its use, such as, reduction in serum testosterone levels due to damage of the testis structure and, consequently, male infertility. The present study aims to evaluate the effects of chronic CsA administration on the ventral prostate tissue (15 mg/kg per d, for 56 days). Stereological, morphometrical, morphological and ultrastructural observations were employed. The plasmatic testosterone and glucose levels were measured. An androgen receptor (AR) immunohistochemical method was applied on ventral prostate sections. Apoptosis was detected with the terminal deoxynucleotidyl transferase dUTP nick end labeling technique. CsA treatment caused reduction in plasmatic testosterone levels and an increase in glycemia. The volume of all ventral prostate tissue components (lumen, epithelium and muscular and nonmuscular stroma) and ventral prostate weight were reduced in the CsA-treated group. Light and transmission electron microscopy confirmed epithelium atrophy of treated animals. There was no alteration of AR expression or apoptotic index. CsA chronic treatment in the therapeutic doses caused damage to prostate tissue of adult Wistar rats, probably due to increase in the glucose levels and reduction in the plasmatic testosterone levels.

MMP-2 and TIMP-2 in the prostates of male and female mongolian gerbils: effects of hormonal manipulation.

TIMPs in the prostates of male and female gerbils and evaluated the effects of testosterone on the expression of these enzymes. Ventral prostates from male gerbils that were either intact or had been castrated for 7 or 21 days, along with prostates from female gerbils that were either intact or had been treated with testosterone for 7 or 21 days, were submitted to histological, stereological and immunohistochemical analyses. Stereology of prostatic components showed significant alterations of tissue compartments in the ventral male prostate after castration, especially after 21 days, with a significant increase in stroma. Administration of testosterone led to disorganization in the female prostate, with a significant increase in collagen fibers and smooth muscle cells after 21 days, along with the development of epithelial lesions such as PINs. MMP-2 increased after 21 days of castration in males; however, the TIMP-2 immunoreaction for this group was weak or absent. In females, the expression of MMP-2 appeared to decrease after 7 days of treatment with testosterone, but after 21 days, both epithelium and stroma showed a stronger reaction for MMP-2 than the controls. The expression of TIMP-2 in the treated females was similar to its expression in the castrated males. We conclude that the distribution of MMPs and TIMPs in both male and female prostates is altered by androgen manipulation, but the mechanism of stromal regulation appears to be distinct between genders because both the lack of T in castrated males and the excess levels of T in treated females lead to the same effect.

Hemoglobin polymorphism and hematological profile of Geoffroy's side-necked turtle (Phrynops geoffroanus, Testudines) in the northwestern region of São Paulo State, Brazil.

Complete blood counts and hemoglobin isoform data were gathered from 36 specimens of the turtle species Phrynops geoffroanus from the northwestern region of São Paulo State, Brazil. They were collected in an urban area. The hemoglobin profiles were obtained after red blood cell lysis and by electrophoretic migration in alkaline pH, acid pH, and neutral pH buffer. The hemoglobin components were confirmed using high-performance liquid chromatography (HPLC). Erythrogram analysis included hematocrit, total hemoglobin concentration, total red blood cell count, and red blood cell indices. The leukogram included a total white blood cell count and a calculation of the percent values of neutrophils, lymphocytes, monocytes, basophils, eosinophils, heterophils, and azurophils. HPLC analysis revealed three hemoglobin components; the first with a concentration of 5.5%, the second was a major component with an average concentration of 67.1%, and the third with a concentration of 28.5%. The hematological profile obtained for these specimens allowed us to establish a pattern for P. geoffroanus in São Paulo State Northwestern region. The average hematocrit values were 22.5% for females and 24.0% for males. For total hemoglobin, we found average values of 6.66 g/dL in females and 7.22 g/dL in males. The number of white blood cells was 2725 x 10(3)/microL for females and 2775 x 10(3)/microL for males. There was a predominance of heterophils, eosinophils, and monocytes in both sexes. No significant differences were found between males and females for hematological profile. The hematological results were compared to literature data for other Chelonia. They were similar to what is known for fresh water turtles.

The adaptive compensations in endocrine pancreas from glucocorticoid-treated rats are reversible after the interruption of treatment.

AIM: Glucocorticoid administration induces insulin resistance (IR) and enhances islet mass and insulin secretion in rodents and humans. Here, we analysed whether these effects are still present after the interruption of dexamethasone treatment. METHODS: Adult Wistar rats were distributed into CTL (daily injection of saline for five consecutive days), DEX (daily injection of 1 mg kg(-1) body wt of dexamethasone for five consecutive days) and DEX(10) (5 days of dexamethasone treatment, followed by a period of 10 days without dexamethasone). RESULTS: In vivo experiments indicated that the marked hyperinsulinemia found in DEX rats during fasting and fed states was normalized in the DEX(10) group. Furthermore, the IR and glucose intolerance observed in DEX were restored in DEX(10) rats. Islets from DEX rats secreted more insulin in response to increasing concentrations of glucose and other metabolic and non-metabolic stimuli, compared with that in the CTL group. The insulin secretion for the most compounds studied returned to CTL values in DEX(10) islets. Increased insulin secretion correlated well with the augmentation in ß-cell proliferation and mass in DEX rats, and these morphological alterations were normalized in islets from DEX(10) rats. In parallel, the increased levels of proteins involved in ß-cell proliferation such as Cd2 and Cdk4 observed in DEX islets were also normalized in DEX(10) islets. CONCLUSION: These data strongly support the view that almost all the morphophysiological alterations induced by dexamethasone in the endocrine pancreas are reverted after discontinuation of the treatment. This information is important, considering the frequent use of glucocorticoids in humans.

Expression of acid phosphatase in the seminiferous epithelium of vertebrates.

Acid phosphatases (AcPs) are known to provide phosphate to tissues that have high energy requirements, especially during development, growth and maturation. During spermatogenesis AcP activity is manifested in heterophagous lysosomes of Sertoli cells. This phagocytic function appears to be hormone-independent. We examined the expression pattern of AcP during the reproductive period of four species belonging to different vertebrate groups: Tilapia rendalli (Teleostei, Cichlidae), Dendropsophus minutus (Amphibia, Anura), Meriones unguiculatus (Mammalia, Rodentia), and Oryctolagus cuniculus (Mammalia, Lagomorpha). To demonstrate AcP activity, cryosections were processed for enzyme histochemistry by a modification of the method of Gömöri. AcP activity was similar in the testes of these four species. Testes of T. rendalli, D. minutus and M. unguiculatus showed an intense reaction in the Sertoli cell region. AcP activity was detected in the testes of D. minutus and O. cuniculus in seminiferous epithelium regions, where cells are found in more advanced stages of development. The seminiferous epithelium of all four species exhibited AcP activity, mainly in the cytoplasm of either Sertoli cells or germ cells. These findings reinforce the importance of AcP activity during the spermatogenesis process in vertebrates.

Matrix metalloproteinase (MMP)-2 and MMP-9 activity and localization during ventral prostate atrophy and regrowth.

Matrix metalloproteinses (MMPs) are enzymes involved in prostatic development, growth, disease-induced tissue remodelling and secretory fluid. Although the prostate function depends upon androgen regulation, the relationship between MMPs and androgen has not been well established. Here, we evaluated MMP-2 and MMP-9 gelatinolytic activity in association with tissue localization during ventral prostate atrophy and regrowth induced by testosterone replacement (TR). Adult male Wistar rats were divided into three experimental groups: control, castrated (CS) and TR 21 days after castration. Ventral prostate (VP) was excised at 3, 5, 7 and 21 days after castration in CS group, and at 3, 5, 7 and 10 days after TR (4 mg/kg/day) in TR group. The VP was dissected, weighed and processed for histology, immunohistochemistry, ultrastructure and zymography analyses. Castration elicited the typical parenchymal atrophy and stromal condensation. TR induced intense epithelial growth towards the stromal space to restore the prostate histoarchitecture. MMP-2 and MMP-9 immunostaining presented intense reaction in CS and TR groups, mainly in the epithelial and endothelial cells. After TR, a strong immunoreaction for MMP-2 was observed in the activated stromal fibroblasts. Zymography showed that MMP-2 and MMP-9 activity, mainly the active form, increased after castration. In contrast, TR induced an additional increase in MMP-2 activity, but not in MMP-9. In conclusion, the overall behaviour of MMP-2 and MMP-9 within the prostate under androgen handling is highly complex, as each glandular compartment and cell type is affected differently by the androgenic status. Prostate regrowth appears to involve a more effective participation of MMP-2 in both epithelial and stromal compartments, while MMP-9 plays a major role in the late prostate atrophy and early regrowth.

Short-term antiandrogen flutamide treatment causes structural alterations in somatic cells associated with premature detachment of spermatids in the testis of pubertal and adult guinea pigs.

In spite of widespread application of flutamide in the endocrine therapies of young and adult patients, the side effects of this antiandrogen on spermatogenesis and germ-cell morphology remain unclear. This study evaluates the short-term androgen blockage effect induced by the administration of flutamide to the testes of pubertal (30-day old) and adult (65- and 135-day old) guinea pigs, with an emphasis on ultrastructural alterations of main cell types. The testes removed after 10 days of treatment with either a non-steroidal antiandrogen, flutamide (10 mg/kg of body weight) or a pharmacological vehicle alone were processed for histological, quantitative and ultrastructural analysis. In pubertal animals, flutamide androgenic blockage induces spermatogonial differentiation and accelerates testes maturation, causing degeneration and detachment of primary spermatocytes and round spermatids, which are subsequently found in great quantities in the epididymis caput. In post-pubertal and adult guinea pigs, in addition to causing germ-cell degeneration, especially in primary spermatocytes, and leading to the premature detachment of spherical spermatids, the antiandrogen treatment increased the relative volume of Leydig cells. In addition, ultrastructural evaluation indicated that irrespective of age antiandrogen treatment causes an increase in frequency of organelles involved with steroid hormone synthesis in the Leydig cells and a dramatic accumulation of myelin figures in their cytoplasm and, to a larger degree, in Sertoli cells. In conclusion, the transient exposition of the guinea pigs to flutamide, at all postnatal ages causes some degenerative lesions including severe premature detachment of spermatids and accumulation of myelin bodies in Leydig and Sertoli cells, compromising, at least temporarily, the spermatogenesis.

Characterization of Mongolian gerbil chromatoid bodies and their correlation with nucleolar cycle during spermatogenesis.

The aims of the present study were to monitor the nucleolar cycle in Mongolian gerbil spermiogenesis, to verify the relationship between the nucleolar component and chromatoid body (CB) formation and to investigate the function of this cytoplasmic supramolecular structure in spermatogenic cells. Histological sections of adult seminiferous tubules were analysed cytochemically by light microscopy and ultrastructurally by transmission electron microscopy. The results reveal that in early spermatids, the CB was visualized in association with Golgi vesicles indicating that this structure may participate in the acrosome formation process as had been reported in other rodents. In late spermatids, the CB was observed near the axoneme region suggesting that this structure may support spermatozoon tail formation as happens in other species. Chromatoid body was joined with lipid droplets in this same cell type. This observation should be investigated to verify whether CB may be related to steroidal hormone metabolism. In conclusion, our data showed that there is disintegration of primary spermatocyte nucleoli at the beginning of prophase I and a fraction of this nucleolar material migrates to the cytoplasm, where a specific structure is formed, known as the 'chromatoid body', which apparently participates in some parts of the gerbil spermiogenesis process.

Cellular changes in the prostatic stroma of glucocorticoid-treated rats.

Glucocorticoid hormones (GCs) have been widely used for the treatment of prostate cancer because of their inhibitory property against tumour growth. However, their mechanism of action in the prostate has received little attention. Excess GCs can lead to peripheral insulin resistance resulting in hyperglycaemia and hyperinsulinaemia. Insulin plays an important role as a cellular stimulant and high levels are related to low levels of androgens. Our objective has been to describe the effects of insulin resistance induced by dexamethasone treatment on the morphology of rat ventral prostate. Male adult Wistar rats received daily intraperitoneal injections of dexamethasone or saline for five consecutive days after which the rats were killed and the ventral prostate was removed, weighed and prepared for conventional and transmission electron microscopy (TEM). Dexamethasone treatment resulted in atrophy and decreased proliferative activity of prostatic epithelial cells. TEM analysis revealed changes in the epithelium-stroma interface, with some interruptions in the basement membrane. Fibroblasts showed a secretory phenotype with dilated endoplasmic reticulum. Smooth muscle cells exhibited a contractile pattern with 50% atrophy, an irregular membrane and twisted nuclei. Mitochondrial alterations, such as enlarged size and high electron density in the mitochondrial matrix, were also detected in smooth muscle cells. Insulin resistance induced by dexamethasone is thus associated with epithelial atrophy similar to that described for diabetic rats. However, GCs are responsible for morphological changes in the stromal cell population suggesting the activation of fibroblasts and atrophy of the smooth muscle cells.

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.

Nuclear alterations associated to programmed cell death in larval salivary glands of Apis mellifera (Hymenoptera: Apidae).

The silk glands of bees are a good model for the study of cell death in insects. With the objective to detect the nuclear features during glandular regression stage, larvae at the last instar and pre-pupae were collected and their silk glands were dissected and processed for ultrastructural analysis and histologically for cytochemical and imunocytochemical analysis. The results showed that the cellular nuclei exhibited characteristics of death by atypical apoptosis as well as autophagic cell death. Among the apoptosis characteristic were: nuclear strangulation with bleb formation in some nuclei, DNA fragmentation in most of the nuclei and nucleolar fragmentation. Centripetal chromatin compaction was observed in many nuclei, forming a perichromatin halo differing from typical apoptotic nuclei. With regards to the characteristics of autophagic-programmed cell death, most relevant was the delay in the collapse of many nuclei.

Dexamethasone-induced insulin resistance is associated with increased connexin 36 mRNA and protein expression in pancreatic rat islets.

Augmented glucose-stimulated insulin secretion (GSIS) is an adaptive mechanism exhibited by pancreatic islets from insulin-resistant animal models. Gap junction proteins have been proposed to contribute to islet function. As such, we investigated the expression of connexin 36 (Cx36), connexin 43 (Cx43), and the glucose transporter Glut2 at mRNA and protein levels in pancreatic islets of dexamethasone (DEX)-induced insulin-resistant rats. Study rats received daily injections of DEX (1 mg/kg body mass, i.p.) for 5 days, whereas control rats (CTL) received saline solution. DEX rats exhibited peripheral insulin resistance, as indicated by the significant postabsorptive insulin levels and by the constant rate for glucose disappearance (KITT). GSIS was significantly higher in DEX islets (1.8-fold in 16.7 mmol/L glucose vs. CTL, p < 0.05). A significant increase of 2.25-fold in islet area was observed in DEX vs. CTL islets (p < 0.05). Cx36 mRNA expression was significantly augmented, Cx43 diminished, and Glut2 mRNA was unaltered in islets of DEX vs. CTL (p < 0.05). Cx36 protein expression was 1.6-fold higher than that of CTL islets (p < 0.05). Glut2 protein expression was unaltered and Cx43 was not detected at the protein level. We conclude that DEX-induced insulin resistance is accompanied by increased GSIS and this may be associated with increase of Cx36 protein expression.

Programmed cell death in the larval salivary glands of Apis mellifera (Hymenoptera, Apidae).

The morphological and histochemical features of degeneration in honeybee (Apis mellifera) salivary glands were investigated in 5th instar larvae and in the pre-pupal period. The distribution and activity patterns of acid phosphatase enzyme were also analysed. As a routine,the larval salivary glands were fixed and processed for light microscopy and transmission electron microscopy.Tissue sections were subsequently stained with haematoxylin -eosin,bromophenol blue,silver,or a variant of the critical electrolyte concentration (CEC) method.Ultrathin sections were contrasted with uranyl acetate and lead citrate.Glands were processed for the histochemical and cytochemical localization of acid phosphatase,as well as biochemical assay to detect its activity pattern. Acid phosphatase activity was histochemically detected in all the salivary glands analysed.The cytochemical results showed acid phosphatase in vesicles, Golgi apparatus and lysosomes during the secretory phase and,additionally, in autophagic structures and luminal secretion during the degenerative phase. These findings were in agreement with the biochemical assay. At the end of the 5th instar, the glandular cells had a vacuolated cytoplasm and pyknotic nuclei, and epithelial cells were shed into the glandular lumen.The transition phase from the 5th instar to the pre-pupal period was characterized by intense vacuolation of the basal cytoplasm and release of parts of the cytoplasm into the lumen by apical blebbing; these blebs contained cytoplasmic RNA, rough endoplasmic reticule and, occasionally, nuclear material. In the pre-pupal phase, the glandular epithelium showed progressive degeneration so that at the end of this phase only nuclei and remnants of the cytoplasm were observed.The nuclei were pyknotic,with peripheral chromatin and blebs. The gland remained in the haemolymph and was recycled during metamorphosis. The programmed cell death in this gland represented a morphological form intermediate between apoptosis and autophagy.

Prostatic stromal microenvironment and experimental diabetes.

The diabetes causes alterations in various organ systems, including the male accessory sex glands. The prostate is very important in the reproductive process and it is a frequent target of malignant changes. The aim of this work was to demonstrate the histochemical and ultrastructural alterations in the prostate of diabetic animals. Two groups of animals were utilized: control and non-obese diabetic mice (NOD). Twelve days after the characterization of diabetic status the ventral prostate was collected, fixed in Karnovsky and paraformaldehyde, processed for histochemistry and TEM associated to stereology. The results showed reduction of the epithelial area and increasing of the stromal area with muscular and collagen hypertrophy in the prostatic gland. It was characterized the development of prostatic intraepithelial neoplasia, inflammatory processes and dilation of the organelles involved in the secretory process. It was concluded that diabetes besides damaging the reproductive process, affects the glandular homeostasis favoring the development of prostatic pathologies.