Differentiation of Steroidogenic Cells in the Developing Adrenal Gland ofTestudo hermanniGmelin, 1789 (Chelonian Reptiles)

Abstract

The aim of this study was to investigate the development and differentiation of steroidogenic cells in the embryonic adrenal gland of Testudo hermanni using histological, histochemical, immunohistochemical and ultrastructural methods. The 26 developmental stages were divided into three periods: early (stages 1-18, up to 20 days of incubation), intermediate (stages 19-22, incubation days 21-35) and advanced (stages 23-26, from incubation day 36 to hatching). A small presumptive bud of steroidogenic cells was visible at the end of the early period, protruding into the coelom from the lateral wall of intermediate mesoderm. Ultrastructural characteristics suggested that young and scarcely differentiated cells could already be able to perform steroidogenic activity: lipid droplets, large amount of SER and RER, small rounded mitochondria with variously shaped cristae and dense matrix. The cell membrane showed microvilli and coated pits. During the intermediate period, the interrenal bud deepened into the haemopoietic tissue, close to the mesonephros and the newly formed metanephros. The ultrastructural, immunohistochemical and immunocytochemical characteristics pointed to enhanced steroidogenic activity. The contact with both kidney types (mesonephros and metanephros) continued in the advanced period, and chromaffin cells were also extensively mixed with steroidogenic cells. This is a peculiar feature of chelonian adrenal gland, in comparison with that of other reptiles. The variable cytological characteristics of embryonic steroidogenic cells in the advanced period suggest a four-phase cycle of steroidogenic activity.

The adrenocortical homolog of the beluga sturgeon Huso huso (Chondrostei)

“…The fact that the steroidogenic cells, depending on their functional moment, may appear under different aspects has been observed in various vertebrate classes (Hanke, 1978;Nussdorfer, 1986). Nevertheless, to our knowledge, such a cycle linking the various cyto logical aspects of the steroidogenic cells in the adrenal gland or its homolog among vertebrate species was evidenced, besides the chondrostean Huso huso and the teleost Gasterosteus aculeatus (Civinini et al, 2001;Civinini and Gallo, 2007), in the steroidogenic cells of the developing adrenal gland of Testudo hermanni (Chimenti and Accordi, 2013). Further accurate elec tron microscopic studies could reveal if it is typical of the steroid producing cells in general.…”

Peculiarities of microstructure of the suprarenal glands of rabbits with different types of autonomic tone

“…Some species of amphibians have cells located chaotically and therefore the gland is not divided into zones, and chromaffin cells have granules of adrenaline and noradrenaline (Milano & Accordi, 1986;Capaldo et al, 2006;Crivellato et al, 2009). Seasonal changes in activity of the gland, and also its intrauterine development, as links of philogenesis, were studied in reptiles (Lofts et al, 1971;Rupik, 2002;Chimenti & Accordi, 2013). In the changes, the histochemical peculiarities of chromaffin cells were found (Orezzoli et al, 1994).…”