The Adrenal Gland in Reptilia

Lofts, B.; Callard, İan P.; Callard, Gloria V.

doi:10.1016/b978-0-12-171502-1.50010-1

Cited by 19 publications

(12 citation statements)

References 61 publications

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“…In reptiles, Sanford and Stephens (1988) did not find any effect of ACTH on plasma corticosterone, cortisol, or aldosterone in the turtle Pseudemys scripta. In contrast, ACTH was found to stimulate steroidogenesis (Callard and Callard, 1978;Lofts, 1978). In the lizard Podarcis sicula, ACTH administration enhances corticosteroid production, increasing PNMT activity and increasing the number of adrenaline-producing cells (Laforgia and Varano, 1978;Laforgia and Muoio, 1997).…”

mentioning

confidence: 91%

Release of aldosterone and catecholamines from the interrenal gland of Triturus carnifex in response to adrenocorticotropic hormone (ACTH) administration

Capaldo

Valiante

Varlese

et al. 2004

Journal of Morphology

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The influence of adrenocorticotropic hormone (ACTH) on the interrenal gland of Triturus carnifex was investigated by in vivo administration of synthetic ACTH. The effects were evaluated by examination of the ultrastructural morphological and morphometrical features of the tissues as well as the circulating serum levels of aldosterone, noradrenaline (NA), and adrenaline (A). In June and November, ACTH administration increased aldosterone release (from 281.50 +/- 1.60 pg/ml in carrier-injected newts to 597.02 +/- 3.35 pg/ml in June; from 187.45 +/- 1.34 pg/ml in carrier-injected animals to 651.00 +/- 3.61 pg/ml in November). The steroidogenic cells showed clear signs of stimulation, together with a reduction of lipid content in June and an increase of lipid content in November. Moreover, ACTH administration decreased the mean total number of secretory vesicles in the chromaffin cells in June (from 7.73 +/- 0.60 granules/microm2 in carrier-injected animals to 5.91 +/- 0.40 granules/microm2) and November (from 7.78 +/- 0.75 granules/microm2 in carrier-injected newts to 4.87 +/- 0.40 granules/microm2). In June, however, when T. carnifex chromaffin cells contain almost exclusively NA granules (NA: 7.42 +/- 0.86 granules/microm2; A: 0.32 +/- 0.13 granules/microm2), ACTH decreased NA content (5.52 +/- 0.32 granules/microm2) increasing NA release (from 639.82 +/- 3.30 pg/ml in carrier-injected to 880.55 +/- 4.52 pg/ml). In November, when both catecholamines, NA (3.92 +/- 0.34 granules/microm2) and A (3.84 +/- 0.33 granules/microm2), are present in the chromaffin cells, ACTH administration reduced A content (1.02 +/- 0.20 granules/microm2), enhancing adrenaline secretion (from 681.30 +/- 3.62 pg/ml in carrier-injected newts to 1,335.73 +/- 9.03 pg/ml). The results of this study indicate that ACTH influences the steroidogenic tissue, eliciting aldosterone release. The effects on the chromaffin tissue, increase of NA or A secretion, according to the period of chromaffin cell functional cycle, may be direct and/or mediated through the increase of aldosterone release. Finally, the lack of an increase of A content in the chromaffin cells, or A serum level, following ACTH administration in June might suggest an independence of PNMT enzyme on corticosteroids.

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confidence: 91%

Release of aldosterone and catecholamines from the interrenal gland of Triturus carnifex in response to adrenocorticotropic hormone (ACTH) administration

Capaldo

Valiante

Varlese

et al. 2004

Journal of Morphology

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“…In primitive amphibians like gymnophiona and urodeles it consists of small bodies; in advanced anuran amphibians it is arranged in a stripe (Grassi Milano and Accordi 1986;Accordi and Grassi Milano 1990). In amniotes, the adrenal gland is arranged to form a compact organ surrounded by connective tissue (Coupland 1965;Gabe 1970;Holmes and Phillips 1976;Lofts 1978;Balment et al 1980). Except for turtles, the reptile adrenal gland lost direct contact with the kidney, being arranged in an encapsulated body at its cephalic tip, as in birds and mammals.…”

Section: Introductionmentioning

confidence: 97%

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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“…A parallel adrenocortical-gonadal cycle has also been reported in another species of turtle (Combescot, 1955) and other reptiles (Lofts, 1978). Furthermore, exogenous FSH and LH also caused adrenocortical stimulation in the same turtle species Lissemys (Ray, 1986).…”

Section: Discussionmentioning

confidence: 83%

Seasonal Adrenocortical Cycle of the Female Soft-shelled Turtle Lissemys p. punctata

Ray¹,

Chaudhuri-Sengupta²,

Maiti³

2003

Biological Rhythm Research

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The seasonal adrenocortical cycle in the female soft-shelled turtle Lissemys p. punctata was investigated by examining the adrenal gland once a month throughout the year from gravimetric, histological, histochemical and biochemical standpoints. The adrenal gland weight, nuclear diameter, histochemically detected 3b-hydroxysteroid dehydrogenase activity, corticosterone and RNA concentrations, and acid phosphatase and alkaline phosphatase activities began to increase from early summer (March-June), reached a peak in late summer (July-August) and declined subsequently (September-February), but adrenal cholesterol and ascorbic acid levels together with histochemically demonstrated sudanophilic lipids were altered reversely to those of other parameters. The results indicate that adrenocortical activity varies seasonally, being higher in early summer, highest in late summer and low in winter, that coincides with the seasonal ovarian cycle in Lissemys. It is suggested that there is a correlation between ovarian and adrenocortical activity and that the seasonality in adrenocortical activity may be related to environmental (temperature) and hormonal factors in the soft-shelled turtle.

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The Adrenal Gland in Reptilia

Cited by 19 publications

References 61 publications

Release of aldosterone and catecholamines from the interrenal gland of Triturus carnifex in response to adrenocorticotropic hormone (ACTH) administration

Release of aldosterone and catecholamines from the interrenal gland of Triturus carnifex in response to adrenocorticotropic hormone (ACTH) administration

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

Seasonal Adrenocortical Cycle of the Female Soft-shelled Turtle Lissemys p. punctata

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