... Laforgia, V and Capaldo, A. 1991. ... hormones induce changes in metabolism and/or ionic regu... more ... Laforgia, V and Capaldo, A. 1991. ... hormones induce changes in metabolism and/or ionic regulation that work to combat physiological factors and to eliminate or to neutralize the stressful stimulus, allowing the organism to adapt to its environment, and to survive (Norris 200718. ...
The influence of adrenocorticotropic hormone (ACTH) on the interrenal gland of Triturus carnifex ... more 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 Ϯ 1.60 pg/ml in carrierinjected newts to 597.02 Ϯ 3.35 pg/ml in June; from 187.45 Ϯ 1.34 pg/ml in carrier-injected animals to 651.00 Ϯ 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 Ϯ 0.60 granules/ m 2 in carrier-injected animals to 5.91 Ϯ 0.40 granules/ m 2) and November (from 7.78 Ϯ 0.75 granules/m 2 in carrier-injected newts to 4.87 Ϯ 0.40 granules/m 2). In June, however, when T. carnifex chromaffin cells contain almost exclusively NA granules (NA: 7.42 Ϯ 0.86 granules/m 2 ; A: 0.32 Ϯ 0.13 granules/m 2), ACTH decreased NA content (5.52 Ϯ 0.32 granules/m 2) increasing NA release (from 639.82 Ϯ 3.30 pg/ml in carrier-injected to 880.55 Ϯ 4.52 pg/ml). In November, when both catecholamines, NA (3.92 Ϯ 0.34 granules/m 2) and A (3.84 Ϯ 0.33 granules/m 2), are present in the chromaffin cells, ACTH administration reduced A content (1.02 Ϯ 0.20 granules/m 2), enhancing adrenaline secretion (from 681.30 Ϯ 3.62 pg/ml in carrier-injected newts to 1,335.73 Ϯ 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.
The adrenal gland is a complex endocrine organ composed of two components: a steroidogenic tissue... more The adrenal gland is a complex endocrine organ composed of two components: a steroidogenic tissue, which produces steroid hormones, and a chromaffin tissue, which mainly produces norepinephrine and epinephrine. Through evolution, their relationships with each other changed. They begin as isolated chromaffin and steroidogenic cell aggregates, typical of fish, and end with the advanced compact gland, typical of mammals, which consists of an external steroidogenic cortical zone and an internal chromaffin medullary zone. The adrenal gland of reptiles is unique because, with few exceptions, it is near the gonads and genital ducts, and the chromaffin and steroidogenic tissues are closely associated. However, the degree of mixing is variable. For example, in Squamata, the mixing degree of chromaffin and steroidogenic tissues, their reciprocal position in the gland, and the relative quantities of norepinephrine and epinephrine secreted by the chromaffin cells are extremely variable. This va...
The issue of Open Zoology Journal entitled: "Endocrine disruption in Rana temporaria and Podarcis... more The issue of Open Zoology Journal entitled: "Endocrine disruption in Rana temporaria and Podarcis sicula", focuses on one of the most important problems in our time, the increasing environmental contamination, and the consequent damages to amphibians and reptiles. Five papers deal with this topic. The first paper by Brande-Lavridsen et al. [1] shows that age and size at metamorphosis of tadpoles of the common frog, Rana temporaria, can be influenced by two known endocrine disruptors, the estrogenic pharmaceutical 17-ethinylestradiol and the antiandrogenic/antiestrogenic fungicide prochloraz. In the second paper, by Sciarrillo et al. [2], the Authors investigate the effects of nonylphenol, an estrogenic-like compound widespread in the aquatic environment, on the thyroid of the lizard Podarcis sicula. The results show a structural and functional disruption of the thyroid gland. The next three papers examine different effects of a heavy metal, cadmium, on the lizard Podarcis sicula. The third paper, by De Falco et al. [3], investigates the changes in the adrenal gland morphology of the lizard following the exposure to cadmium. This metal impairs the steroidogenic tissue and induces steroidogenic cord hyperplasia, disorganization of steroidogenic parenchyma until necrotic degeneration. It in turn evokes macrophage infiltration. The fourth paper, by Favorito et al. [4] shows an alteration of the normal endocrine function of the pituitary gland of the lizard Podarcis sicula following an acute exposure to cadmium. The last paper, by Simoniello et al. [5] shows that cadmium in Podarcis sicula stimulates oogonial proliferation and oocyte recruitment by mimicking gonadotropins activity. The metal also exerts toxic effects on the growing follicles thus reducing fecundity and the reproductive performance. This issue increases the knowledge of the effects of some environmental pollutants on amphibians and reptiles, two groups of organisms increasingly threatened by pollution, and now at risk of extinction. Moreover, it highlights the risks human health is exposed to.
The action of the regulatory neuropeptides vasoactive intestinal polypeptide (VIP) and pituitary ... more The action of the regulatory neuropeptides vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) carries out through the shared receptors VPAC1 and VPAC2 and the exclusive PACAP receptor PAC1, all of which are G protein-coupled receptors. Formerly, we showed that the administration of both peptides enhance catecholamine, corticosterone and aldosterone release from adrenal cell co-culture. Further, the distribution of VIP and PACAP receptors in the adrenal glands of the Italian wall lizard, Podarcis sicula, was previously demonstrated: VPAC1 was found within steroidogenic tissue, VPAC2 and PAC1 within chromaffin tissue. In the present study we investigated the c-AMP signaling pathway involved in the VIP and PACAP-induced secretion of adrenal cell co-cultures. Using VPAC1 antagonist [Ac-His1, D-Phe2,Lys15,Arg16]VIP-(3-7),GH-releasing factor-(8-27)-NH2 (VPAC1-A), the PAC1 antagonist PACAP6-38 (PAC1-A) and VPAC2 immunoneutralized cells, i...
The administration of insulin to Triturus cristatus confirms its action in depletion of the adren... more The administration of insulin to Triturus cristatus confirms its action in depletion of the adrenalin (A) granules of the adrenal chromaffin cells and the subsequent activation of phenylethanolamine‐N‐methyltransferase (PNMT). Treatment was carried out in March, when noradrenalin (NA) and A granules are present in almost equal quantities in the chromaffin cells, and in June, when NA granules largely prevail. After insulin administration, adrenalin content of the specimens treated in March decreases from 2.44 granules/μm2 to 0.28 granules/μm2; on the other hand, adrenalin content of the specimens treated in June increases from 0.19 granules/μm2 to 0.31 granules/μm2. These results suggest that in T. cristatus insulin acts both as an adrenalin‐releasing agent and as a stimulator of PNMT activity.
The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-relate... more The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family that occurs in two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. First discovered in the brain, it was then localized in several peripheral ...
If severe enough, periods of acute stress in animals may be associated with the release of catech... more If severe enough, periods of acute stress in animals may be associated with the release of catecholamine hormones (noradrenaline and adrenaline) into the circulation; a response termed the acute humoral adrenergic stress response. The release of catecholamines from the sites of storage, the chromaffin cells, is under neuroendocrine control, the complexity of which appears to increase through phylogeny. In the agnathans, the earliest branching vertebrates, the chromaffin cells which are localized predominantly within the heart, lack neuronal innervation and thus catecholamine secretion in these animals is initiated solely by humoral mechanisms. In the more advanced teleost fish, the chromaffin cells are largely confined to the walls of the posterior cardinal vein at the level of the head kidney where they are intermingled with the steroidogenic interrenal cells. Catecholamine secretion from teleost chromaffin cells is regulated by a host of cholinergic and non-cholinergic pathways that ensure sufficient redundancy and flexibility in the secretion process to permit synchronized responses to a myriad of stressors. The complexity of catecholamine secretion control mechanisms continues through the amphibians, reptiles and birds although neural (cholinergic) regulation may become increasingly important in birds. Discrete adrenal glands are present in the non-mammalian tetrapods but unlike in mammals, there is no clear division of a steroidogenic cortex and a chromaffin cell enriched medulla. However, in all groups, there is an obvious intermingling of chromaffin and steroiodogenic cells. The association of the two cell types may be particularly important in the amphibians and birds because like in mammals, the enzyme catalysing the methylation of noradrenaline to adrenaline, PNMT, is under the control of the steroid cortisol.
Because of the similarities of the adrenal glands of mammals and of the lizard Podarcis s. sicula... more Because of the similarities of the adrenal glands of mammals and of the lizard Podarcis s. sicula, the latter has already been the subject of various studies on the effects of Propofol and other anaesthetics. Because a relationship between the activities of the thyroid and adrenal glands of this species has been demonstrated, the authors administered Propofol to a species of lizard to investigate its effects on the thyroid gland. Propofol inhibited thyroid activity, promoted steroid synthesis, and caused the contemporaneous appearance of both adrenaline and noradrenaline granules in the cytoplasm of the chromaffin cells. These results suggest that inhibition of the activity of the thyroid gland is secondary to the action of Propofol on the adrenal gland.
The morphology of the adrenal gland and relationships between noradrenalin (NA) and adrenalin (A)... more The morphology of the adrenal gland and relationships between noradrenalin (NA) and adrenalin (A) cells were studied in selected species of the genus Podarcis. As in other previously-studied genera, the morphology of the adrenal gland is not homogeneous, and the species examined can be divided into two groups according to the relationship between chromaffin and steroidogenic tissue. Podarcis taurica and P. hispanica, in which the two tissues are strongly separated, belong to one group. P. wagleriana, P. muralis, P. sicula, P. pelofionnesiaca and P. melisellensis belong to a second group in which dorsal chromaffin ribbons send digitations between the steroidogenic cords. The NA/A cell ratio is higher in species of the first group than in those of the second.
Galanin (GAL) is a 29-amino acid residue neuropeptide, which was initially isolated from porcine ... more Galanin (GAL) is a 29-amino acid residue neuropeptide, which was initially isolated from porcine intestine extracts and since then, widely found in a variety of vertebrate organs, in correlation with multiple neuro-hormonal actions exerted and so receiving a constantly growing attention. Moreover, although the studies undertaken so far suggest a local intrathyroidal peptidergic regulatory action, the exact role of GAL on thyroid gland remains to be established. The aim of this study was to determine in the lizard, Podarcis sicula, (1) the presence of GAL immunoreactivity in the thyroid gland and (2) the short-and long-term effects of in vivo GAL administration by intraperitoneal injection on thyroid gland physiology. First of all, the presence of GAL in the thyroid gland of P. sicula was demonstrated by immunohistochemical technique (avidin-biotin-peroxidase complex-ABC method). Second, the role of GAL in the control of thyroid gland activity was studied in vivo using light microscopy (LM) technique coupled to a specific radioimmunoassay for thyroid-stimulating hormone (TSH) and thyroid hormones (T 4 and T 3). Prolonged GAL administration [(0.4 mg/100 g body wt)/day] increased T 4 and T 3 release, but decreased the plasma concentration of TSH. In addition, using LM clear signs of stimulation of the thyroid gland were observed. These findings suggest that systemic administration of GAL was able to stimulate the thyroid gland of the lizard both at morphological and physiological level.
... Laforgia, V and Capaldo, A. 1991. ... hormones induce changes in metabolism and/or ionic regu... more ... Laforgia, V and Capaldo, A. 1991. ... hormones induce changes in metabolism and/or ionic regulation that work to combat physiological factors and to eliminate or to neutralize the stressful stimulus, allowing the organism to adapt to its environment, and to survive (Norris 200718. ...
The influence of adrenocorticotropic hormone (ACTH) on the interrenal gland of Triturus carnifex ... more 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 Ϯ 1.60 pg/ml in carrierinjected newts to 597.02 Ϯ 3.35 pg/ml in June; from 187.45 Ϯ 1.34 pg/ml in carrier-injected animals to 651.00 Ϯ 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 Ϯ 0.60 granules/ m 2 in carrier-injected animals to 5.91 Ϯ 0.40 granules/ m 2) and November (from 7.78 Ϯ 0.75 granules/m 2 in carrier-injected newts to 4.87 Ϯ 0.40 granules/m 2). In June, however, when T. carnifex chromaffin cells contain almost exclusively NA granules (NA: 7.42 Ϯ 0.86 granules/m 2 ; A: 0.32 Ϯ 0.13 granules/m 2), ACTH decreased NA content (5.52 Ϯ 0.32 granules/m 2) increasing NA release (from 639.82 Ϯ 3.30 pg/ml in carrier-injected to 880.55 Ϯ 4.52 pg/ml). In November, when both catecholamines, NA (3.92 Ϯ 0.34 granules/m 2) and A (3.84 Ϯ 0.33 granules/m 2), are present in the chromaffin cells, ACTH administration reduced A content (1.02 Ϯ 0.20 granules/m 2), enhancing adrenaline secretion (from 681.30 Ϯ 3.62 pg/ml in carrier-injected newts to 1,335.73 Ϯ 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.
The adrenal gland is a complex endocrine organ composed of two components: a steroidogenic tissue... more The adrenal gland is a complex endocrine organ composed of two components: a steroidogenic tissue, which produces steroid hormones, and a chromaffin tissue, which mainly produces norepinephrine and epinephrine. Through evolution, their relationships with each other changed. They begin as isolated chromaffin and steroidogenic cell aggregates, typical of fish, and end with the advanced compact gland, typical of mammals, which consists of an external steroidogenic cortical zone and an internal chromaffin medullary zone. The adrenal gland of reptiles is unique because, with few exceptions, it is near the gonads and genital ducts, and the chromaffin and steroidogenic tissues are closely associated. However, the degree of mixing is variable. For example, in Squamata, the mixing degree of chromaffin and steroidogenic tissues, their reciprocal position in the gland, and the relative quantities of norepinephrine and epinephrine secreted by the chromaffin cells are extremely variable. This va...
The issue of Open Zoology Journal entitled: "Endocrine disruption in Rana temporaria and Podarcis... more The issue of Open Zoology Journal entitled: "Endocrine disruption in Rana temporaria and Podarcis sicula", focuses on one of the most important problems in our time, the increasing environmental contamination, and the consequent damages to amphibians and reptiles. Five papers deal with this topic. The first paper by Brande-Lavridsen et al. [1] shows that age and size at metamorphosis of tadpoles of the common frog, Rana temporaria, can be influenced by two known endocrine disruptors, the estrogenic pharmaceutical 17-ethinylestradiol and the antiandrogenic/antiestrogenic fungicide prochloraz. In the second paper, by Sciarrillo et al. [2], the Authors investigate the effects of nonylphenol, an estrogenic-like compound widespread in the aquatic environment, on the thyroid of the lizard Podarcis sicula. The results show a structural and functional disruption of the thyroid gland. The next three papers examine different effects of a heavy metal, cadmium, on the lizard Podarcis sicula. The third paper, by De Falco et al. [3], investigates the changes in the adrenal gland morphology of the lizard following the exposure to cadmium. This metal impairs the steroidogenic tissue and induces steroidogenic cord hyperplasia, disorganization of steroidogenic parenchyma until necrotic degeneration. It in turn evokes macrophage infiltration. The fourth paper, by Favorito et al. [4] shows an alteration of the normal endocrine function of the pituitary gland of the lizard Podarcis sicula following an acute exposure to cadmium. The last paper, by Simoniello et al. [5] shows that cadmium in Podarcis sicula stimulates oogonial proliferation and oocyte recruitment by mimicking gonadotropins activity. The metal also exerts toxic effects on the growing follicles thus reducing fecundity and the reproductive performance. This issue increases the knowledge of the effects of some environmental pollutants on amphibians and reptiles, two groups of organisms increasingly threatened by pollution, and now at risk of extinction. Moreover, it highlights the risks human health is exposed to.
The action of the regulatory neuropeptides vasoactive intestinal polypeptide (VIP) and pituitary ... more The action of the regulatory neuropeptides vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) carries out through the shared receptors VPAC1 and VPAC2 and the exclusive PACAP receptor PAC1, all of which are G protein-coupled receptors. Formerly, we showed that the administration of both peptides enhance catecholamine, corticosterone and aldosterone release from adrenal cell co-culture. Further, the distribution of VIP and PACAP receptors in the adrenal glands of the Italian wall lizard, Podarcis sicula, was previously demonstrated: VPAC1 was found within steroidogenic tissue, VPAC2 and PAC1 within chromaffin tissue. In the present study we investigated the c-AMP signaling pathway involved in the VIP and PACAP-induced secretion of adrenal cell co-cultures. Using VPAC1 antagonist [Ac-His1, D-Phe2,Lys15,Arg16]VIP-(3-7),GH-releasing factor-(8-27)-NH2 (VPAC1-A), the PAC1 antagonist PACAP6-38 (PAC1-A) and VPAC2 immunoneutralized cells, i...
The administration of insulin to Triturus cristatus confirms its action in depletion of the adren... more The administration of insulin to Triturus cristatus confirms its action in depletion of the adrenalin (A) granules of the adrenal chromaffin cells and the subsequent activation of phenylethanolamine‐N‐methyltransferase (PNMT). Treatment was carried out in March, when noradrenalin (NA) and A granules are present in almost equal quantities in the chromaffin cells, and in June, when NA granules largely prevail. After insulin administration, adrenalin content of the specimens treated in March decreases from 2.44 granules/μm2 to 0.28 granules/μm2; on the other hand, adrenalin content of the specimens treated in June increases from 0.19 granules/μm2 to 0.31 granules/μm2. These results suggest that in T. cristatus insulin acts both as an adrenalin‐releasing agent and as a stimulator of PNMT activity.
The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-relate... more The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family that occurs in two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. First discovered in the brain, it was then localized in several peripheral ...
If severe enough, periods of acute stress in animals may be associated with the release of catech... more If severe enough, periods of acute stress in animals may be associated with the release of catecholamine hormones (noradrenaline and adrenaline) into the circulation; a response termed the acute humoral adrenergic stress response. The release of catecholamines from the sites of storage, the chromaffin cells, is under neuroendocrine control, the complexity of which appears to increase through phylogeny. In the agnathans, the earliest branching vertebrates, the chromaffin cells which are localized predominantly within the heart, lack neuronal innervation and thus catecholamine secretion in these animals is initiated solely by humoral mechanisms. In the more advanced teleost fish, the chromaffin cells are largely confined to the walls of the posterior cardinal vein at the level of the head kidney where they are intermingled with the steroidogenic interrenal cells. Catecholamine secretion from teleost chromaffin cells is regulated by a host of cholinergic and non-cholinergic pathways that ensure sufficient redundancy and flexibility in the secretion process to permit synchronized responses to a myriad of stressors. The complexity of catecholamine secretion control mechanisms continues through the amphibians, reptiles and birds although neural (cholinergic) regulation may become increasingly important in birds. Discrete adrenal glands are present in the non-mammalian tetrapods but unlike in mammals, there is no clear division of a steroidogenic cortex and a chromaffin cell enriched medulla. However, in all groups, there is an obvious intermingling of chromaffin and steroiodogenic cells. The association of the two cell types may be particularly important in the amphibians and birds because like in mammals, the enzyme catalysing the methylation of noradrenaline to adrenaline, PNMT, is under the control of the steroid cortisol.
Because of the similarities of the adrenal glands of mammals and of the lizard Podarcis s. sicula... more Because of the similarities of the adrenal glands of mammals and of the lizard Podarcis s. sicula, the latter has already been the subject of various studies on the effects of Propofol and other anaesthetics. Because a relationship between the activities of the thyroid and adrenal glands of this species has been demonstrated, the authors administered Propofol to a species of lizard to investigate its effects on the thyroid gland. Propofol inhibited thyroid activity, promoted steroid synthesis, and caused the contemporaneous appearance of both adrenaline and noradrenaline granules in the cytoplasm of the chromaffin cells. These results suggest that inhibition of the activity of the thyroid gland is secondary to the action of Propofol on the adrenal gland.
The morphology of the adrenal gland and relationships between noradrenalin (NA) and adrenalin (A)... more The morphology of the adrenal gland and relationships between noradrenalin (NA) and adrenalin (A) cells were studied in selected species of the genus Podarcis. As in other previously-studied genera, the morphology of the adrenal gland is not homogeneous, and the species examined can be divided into two groups according to the relationship between chromaffin and steroidogenic tissue. Podarcis taurica and P. hispanica, in which the two tissues are strongly separated, belong to one group. P. wagleriana, P. muralis, P. sicula, P. pelofionnesiaca and P. melisellensis belong to a second group in which dorsal chromaffin ribbons send digitations between the steroidogenic cords. The NA/A cell ratio is higher in species of the first group than in those of the second.
Galanin (GAL) is a 29-amino acid residue neuropeptide, which was initially isolated from porcine ... more Galanin (GAL) is a 29-amino acid residue neuropeptide, which was initially isolated from porcine intestine extracts and since then, widely found in a variety of vertebrate organs, in correlation with multiple neuro-hormonal actions exerted and so receiving a constantly growing attention. Moreover, although the studies undertaken so far suggest a local intrathyroidal peptidergic regulatory action, the exact role of GAL on thyroid gland remains to be established. The aim of this study was to determine in the lizard, Podarcis sicula, (1) the presence of GAL immunoreactivity in the thyroid gland and (2) the short-and long-term effects of in vivo GAL administration by intraperitoneal injection on thyroid gland physiology. First of all, the presence of GAL in the thyroid gland of P. sicula was demonstrated by immunohistochemical technique (avidin-biotin-peroxidase complex-ABC method). Second, the role of GAL in the control of thyroid gland activity was studied in vivo using light microscopy (LM) technique coupled to a specific radioimmunoassay for thyroid-stimulating hormone (TSH) and thyroid hormones (T 4 and T 3). Prolonged GAL administration [(0.4 mg/100 g body wt)/day] increased T 4 and T 3 release, but decreased the plasma concentration of TSH. In addition, using LM clear signs of stimulation of the thyroid gland were observed. These findings suggest that systemic administration of GAL was able to stimulate the thyroid gland of the lizard both at morphological and physiological level.
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Papers by Anna Capaldo