Development of the Adrenal Gland in the Tropical Lizard Calotes versicolor

Doddamani, Laxmi S.

doi:10.1006/gcen.1999.7385

Cited by 11 publications

(12 citation statements)

References 15 publications

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“…The egg incubation period (50 days at 37°C) was divided into three parts (early, intermediate and advanced), according to the morphological characteristics of the chromaffin cells and to their organization with respect to the kidney and to the steroidogenic cells. Other authors described several periods in different species: Rupik (2002) divided the development of the grass snake Natrix natrix into six phases; Doddamani (2000) divided the development of the red-headed lizard Calotes versicolor into four periods. The chromaffin cells derive from the sympathoadrenal cells, which represent a major sublineage of the trunk neural crest cells, together with the sympathetic neuronal elements (Le Douarin 2004).…”

Section: Discussionmentioning

confidence: 99%

Differentiation of chromaffin cells in the developing adrenal gland of Testudo hermanni

et al. 2006

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The aim of this study was to investigate the development and differentiation of chromaffin cells in the adrenal gland of the turtle Testudo hermanni during ontogenesis using histological, immunocytochemical and ultrastructural methods. The 26 developmental stages were divided into three periods: in the early period (stages 1-18, up to 20 days of incubation at 37 degrees Celsius and 85% humidity), the chromaffin cells were observed from stage 12. They followed a ventro-lateral migration pathway with respect to the notochord and dorsal aorta, forming groups embedded in undifferentiated mesenchymal tissue. They reached the kidney surface only at the end of this period. Under the EM the chromaffin cells showed typical embryonic characters, such as rounded shape, high nucleus/plasmatic ratio, cell membrane with elongated processes; the cytoplasm contained a large number of free ribosomes, Golgi complexes, RER and a few chromaffin granules distributed in small sets. The granules were small and displayed a high electrondensity. Numerous unmyelinated fibres ran close to the chromaffin cells. At the end of this period both nervous elements and chromaffin cells were positive to the antigen for DbetaH. The intermediate period (stages 19-22, incubation days 21-35) was characterized by the first occurrence of steroidogenic cells on the ventro-medial kidney surface. Some chromaffin cells were still found in the same position, whereas other cells were still migrating, maintaining their embryonic character. It was possible to divide the secretory granules into two types according to their shape and electrondensity: the more numerous N-type granules had a dark content, whereas the small number of A-type granules (consistent with the scarce PNMT reaction) displayed a light content. They occurred for the first time in this period. In the advanced period (stages 23-26, from incubation day 36 to hatching) the adrenal gland reached its definitive shape, although remaining immature; groups of variously sized chromaffin cells intermingled with steroidogenic cells, both lying on the kidney surface. Chromaffin granules were more numerous and larger than in the previous stages, frequently mingling in the same cell. A migration pathway of the chromaffin cells along the nerve fibres can be hypothesized on the basis of their common origin and closeness. The polymorphic shape of chromaffin cells with long cytoplasmic processes also accounts for their migrating fitness. We can assume that steroidogenic differentiation from the mesodermic blastema begins after the first chromaffin cells have completed their migration.

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Section: Discussionmentioning

confidence: 99%

Differentiation of chromaffin cells in the developing adrenal gland of Testudo hermanni

et al. 2006

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“…For the demonstration of G-6-PDH, D-glucose-6 phosphate-disodium salt (1.5 mg/m1) was the substrate. The preparation of incubation media and other details of protocol have already been described (Doddamani, 2000). All chemicals were obtained from Sigma Chemical Company.…”

Section: Enzyme Histochemistrymentioning

confidence: 99%

“…Further, histoenzymology of the developing ovary (Doddamani,'94) and ontogenic steroidogenesis of the adrenal gland of C. versicolor (Doddamani, 2000) have already been reported. The proposed work is to study the embryogenesis of the testis,-with the following objectives : (i) the day of onset of testis differentiation, (ii) the differentiation and development of Sertoli and Leydig cells, (iii) the quantitative estimation of germ cells in the developing testis and (iv) the onset of steroidogenesis, steroidogenic cellular sites and their ability to synthesize C-18, C-19 and C-21 steroid hormones during the embryogenesis of the testis in the tropical oviparous lizard, C. versicolor, from the day of oviposition (stage 27) to 60 days after hatching.…”

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confidence: 94%

“…Further, the presence of D 5 -3b-HSDH enzyme activity in the developing testis of C. versicolor indicates the potency of these cells to synthesize to convert D 5 -3b-hydroxysteroids into 4-3-ketosteroids, a major step involved in the early synthesis of biologically active steroid hormones (Hanukoglu,'92). My earlier study on the developing ovary (Doddamani,'94) and the adrenal gland (Doddamani, 2000) in C. versicolor revealed that the adrenocortical cells attain steroidogenic potential earlier than gonads. Hence, the likelihood of adrenal steroid action on gonadal differentiation cannot be ruled out.…”

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confidence: 98%

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Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Doddamani

2006

J. Exp. Zool.

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The differentiation and development of the testis in the lizard Calotes versicolor was studied histologically and histoenzymatically from the day of oviposition (stage 27) to 2 months after hatching. The study reveals the appearance of the gonadal component as a genital ridge at stage 27. The first sign of testis differentiation is observed at stage 33, which displays a well-developed medulla consisting of seminiferous cords comprising Pre-Sertoli cells. The sex differentiation of the embryonic gonads occurs at stage 34. At this stage, seminiferous cords of the testis are prominent and extensive with many pre-Sertoli cells and few spermatogonia. The interstitial space consists of immature fibroblast-type Leydig cells. Pre-Sertoli cells of the seminiferous cords differentiate into Sertoli cells with a triangular nucleus becoming apparent around stages 36-37. The fibroblast-like Leydig cells differentiate into round matured Leydig cells at stage 40. Quantitative estimation of germ cells reveals that the number of germ cells increases in individual gonads, and in 5-day-old hatchling's, this number multiplies by manifold. Spermatogonia show reductional division in the testis of 1-day-old hatchlings. Histochemical localization of Delta5-3beta-HSDH and G-6-PDH activity appears in the seminiferous cords (medulla) of the testis after sexual differentiation (stage 36), indicating that the embryonic medulla is the site of steroidogenesis and not the cortex in C. versicolor. This study also suggests that morphological differentiation of the gonad precedes detectable steroidogenesis in this species. In 10-day-old hatchling's, Delta5-3beta-HSDH activity is seen in the interstitial cells of the testis, which, however, is not detected in the seminiferous tubules. The intensity of the enzyme activity remains more or less the same in the testis up to 10 days after hatching and begins to increase thereafter. The increase in steroidogenesis parallels the progressive post-hatching increase of the interstitial/Leydig cells.

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“…Doddamani (2000) e Rupik (2002) demonstraram que a diferenciação de cromafinoblastos em células cromafins é, provavelmente, estimulada pela influência dos hormônios que são produzidos pelas células do tecido interrenal.…”

Section: A Glândula Adrenal Dos Répteisunclassified

Determinação dos níveis séricos de corticosterona e hormônios esteróides sexuais, induzidos pelo estresse da contenção física e da extração de veneno, em Bothrops jararaca (Ophidia: Viperidae).

Grego¹

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Development of the Adrenal Gland in the Tropical Lizard Calotes versicolor

Cited by 11 publications

References 15 publications

Differentiation of chromaffin cells in the developing adrenal gland of Testudo hermanni

Differentiation of chromaffin cells in the developing adrenal gland of Testudo hermanni

Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Determinação dos níveis séricos de corticosterona e hormônios esteróides sexuais, induzidos pelo estresse da contenção física e da extração de veneno, em Bothrops jararaca (Ophidia: Viperidae).

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