Development of Adrenal Glands from the Embryonic Phase to Puberty in Spix's Yellow-toothed Cavies (Galea spixii, Wagler, 1831)

ABSTRACT Several authors have underscored the importance of establishing parameters in morphological development by gender comparison to establish clinical and pre-clinical assays through the use of experimental models. Current research compares the morphometry of right and left adrenal glands of males and females and describes differentiation of the cortex and medulla tissue during the embryonic, pre-puberty and puberty phases in Spix´s yellow-toothed cavies. Embryos aged 22 (22D), 25 (25D), 30 (30D), 40 (44D) and >50 (50D) days of gestation and neonates aged 15 (15DPN) (DPN= Days postnatal), 30 (30DPN) and 90 (90DPN) days after birth were analyzed. Comparisons included morphometric and histological analysis in all periods described. When compared the right and left adrenal glands, results show that the length and width have statistical differences (p<0.05). Statistical difference between right and left glans for weight occurred only after 30D in males and after 50D in females. When compared male and females, no statistical difference in the right and left glands was extant. In the case of tissue differences, the glomerular zone is the first to emerge after 22D, followed by the fasciculate zone after 25D and by the reticular zone during the post-natal period. Medullar tissue was spread between the cortical tissue at the onset of development, establishing itself at the center of the organ since the end of pregnancy (>50D) up to puberty. Considering tissue differentiation, there was no difference between the adrenal glands of male and female cavies or between the right and left adrenal glands.

Morphological and ultrastructural analysis of the tongue of Gracilinanus microtarsus (Wagner, 1842) / Análise morfológica e ultraestrutural da língua da Gracilinanus microtarsus (Wagner, 1842)

The G. microtarsus is a small marsupial belonging to the Didelphidae family and may be found mainly in the Atlantic Rainforest of the Brazilian Southeastern region. G. microtarsus has important ecological importance in the dispersion of seeds of several plant species. Current research characterizes morphologically six tongues of adult male and female specimens, which are fixed in 10% formaldehyde. The tongues were analyzed, measured and photographed "in situ" and "ex situ". Anatomy, light microscopy and ultrastructural analysis were performed. Macroscopically the tongue has root, a fixed body and a free apex. The tongue has fungiform papillae and high conical and acute filiform papillae across the dorsal surface. It also featured three vallate papillae located at the root and marginal fungiform papillae at the apex. Microscopically, the tongue is composed of longitudinal and transversal muscle fibers. Blood vessels, nerves, serous, mucous and mixed acini are found in non-modeled connective tissue. Ventrally, the tongue is lined by a keratinized stratified pavement epithelium. The morphology of the tongue of G. microtarsus resembles that described in carnivores and marsupials Didelphidae regarding its microscopic structure, differing only in the distribution and number of papillae.

O G. microtarsus é um pequeno marsupial pertencente à família Didelphidae, que pode ser encontrado principalmente na Mata Atlântica da região sudeste brasileira. O G. microtarsus possui importância ecológica na dispersão de sementes de diversas espécies de plantas. A pesquisa atual caracteriza morfologicamente as línguas de seis animais adultos, fixados em formol a 10%. As línguas foram analisadas, mensuradas e fotografadas. Foram realizadas análises anatômicas, microscópicas de luz e ultraestruturais. Macroscopicamente a língua possui raiz, um corpo fixo e um ápice livre. A língua possui papilas fungiformes, filiformes cônicas altas e agudas em toda a superfície dorsal. Também possui três papilas valadas localizadas na raiz e papilas fungiformes marginais no ápice da língua. Microscopicamente, a língua é composta por fibras musculares longitudinais e transversais. Os vasos sanguíneos, nervos e ácinos serosos, mucosos e mistos são encontrados em tecido conjuntivo não modelado. Ventralmente, a língua é revestida por um epitélio pavimentoso estratificado queratinizado. A morfologia da língua de G. microtarsus se assemelha ao descrito em carnívoros e marsupiais Didelphidae quanto à sua estrutura microscópica, diferindo apenas na distribuição e número de papilas.

Intrauterine sexual differentiation: biosyntesis and action of sexual steroid hormones

The objective of this review was to describe sexual differentiation events in mammals, relating them to biosynthesis of sexual steroid hormones and their mechanisms of action. Cholesterol is the precursor of sexual steroid hormone biosynthesis via action of several enzymes converting these hormones. Progestagens hormones serve as substrate for the production of androgens, which in turn serve as substrate for estrogen hormones. These hormones are responsible for sexual differentiation and reproductive cycles of mammals. Sexual differentiation process comprises determining the sexual chromosomes XX or XY + SRY and other genes linked to them, differentiation of gonads in testis or ovary, differentiation of internal and external male or female genital organs from undifferentiated anatomical structures present in the embryo, which is dependent on the presence or absence of testes and the production of anti-Müllerian hormone and testosterone; and secondary sexual differentiation, which is the response of various tissues to hormones produced by the gonads, interacting with genes linked to sexual chromosomes to increase or decrease the differences in sexual phenotype. However, some differences between the sexes and some anomalies of sexual differentiation are not explained only by these sexual hormonal effects, but also by the effect of genes encoded in sexual chromosomes.

Morphological study of the male genital organs of Gracilinanus microtarsus / Estudo morfológico dos órgãos genitais masculinos em Gracilinanus microtarsus

Gracilinanus microtarsus is one of the smallest marsupials on earth. Since it spreads seeds, it has great ecological relevance. However, its reproduction data, especially those related to the anatomy of its reproduction apparatus, are scarce in the literature. Current analysis describes the male genital organs of six adult specimens of G. microtarsus. Macroscopic studies were undertaken on dissected organs, whereas histological studies were performed by inclusion technique in paraffin and by hematoxylin and eosin and Masson trichrome staining. The male genital organs of G. microtarsus consist of a penis with bifid glans, two testicles within a pendular scrotum, placed cranially to the penis, featuring a histology consisting of seminiferous tubules with spermatogonic cells, spermatozoa and Sertoli cells, and a peritubular region with Leydig cells. Testicles are closely associated with epididymis with head, body and tail, with histological differences between the different regions. Deferent ducts, spermatic funicles and annexed glands were reported. The latter were composed of prostate glands divided into three distinct segments and bulbourethral glands. Results show that the male reproduction system of G. Microtarsus is anatomically similar to that of Didelphis sp. and other marsupials groups, with slight details such as the site of each organ...

Gracilinanus microtarsus é um dos menores marsupiais do mundo. Possui grande potencial dispersor de sementes e por esta razão apresenta grande importância ecológica. No entanto, dados em relação à reprodução desses animais são escassos na literatura, principalmente, aqueles relacionados à anatomia dos órgãos do aparelho reprodutor. Por essa razão, objetivamos com este estudo realizar uma descrição dos órgãos genitais masculinos em seis exemplares de G. microtarsus adultos. Para tanto, realizamos estudos macroscópicos por dissecação dos órgãos e estudos histológicos por técnica de inclusão em parafina e coloração em hematoxilina e eosina, e tricromo de Masson. Encontramos, que os órgãos genitais masculinos e glândulas acessórias em G. microtarsus são representados por dois testículos localizados dentro de um escroto pendular, posicionados cranialmente ao pênis, cuja histologia revelou túbulos seminíferos com espermatogônias, espermatozoides e células de Sertoli e região peritubular com células de Leydig; testículos em íntima associação com os epidídimos, divididos em cabeça, corpo e cauda, com diferenças histológicas entre as diferentes regiões; ductos deferentes; funículo espermático; glândulas anexas compostas pelas glândulas prostáticas divididas em três distintos segmentos e glândulas bulbouretrais; uretra pélvica e peniana e um pênis com glande bífida. Concluímos que os órgãos genitais e as glândulas acessórias masculina de G. microtarsus, anatomicamente são muito semelhantes aos dos Didelphis sp. e outros grupos de marsupiais, diferenciando-se apenas em alguns detalhes, como a localização de cada órgão...