Arginine vasotocin (AVT) and AVT-related peptide are major aldosterone-releasing factors in the bullfrog neurointermediate lobe

Iwamuro, Shawichi; Hayashi, Hiroaki; Yamashita, Masamichi; Kikuyama, Sakaé

doi:10.1016/0016-6480(91)90089-o

Cited by 18 publications

(4 citation statements)

References 15 publications

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“…Several subsequent studies conducted in vitro confirmed that AVP could stimulate directly aldosterone secretion, not only in rat adrenal glomerulosa cells (40), but also in humans (41), cats (42), sheep (43), dogs (34), cattle (44) and rabbits (45), as well as in the interrenal tissue of frogs (46,47). AVP stimulates aldosterone secretion by about two fold, which is much lower than what has been observed with ACTH (ten-to twentyfold increase).…”

Section: Adrenalsteroid Secretionmentioning

confidence: 86%

Regulation of Adrenocortical Function by Vasopressin

Gallo‐Payet

Guillon

1998

Horm Metab Res

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Accumulating data obtained from various animal species indicate that vasopressin (AVP) participates in the regulation of adrenocortical function. AVP doubled aldosterone and cortisol secretion but did not affect corticosterone secretion. Pharmacological studies indicate that the AVP receptors in the cortex belong to the V1 a subtype. Activation of V1 a receptors induces breakdown of membrane phosphoinositides, with subsequent accumulation of inositol phosphates and diacylglycerol. These effects occur after receptor binding, G-protein activation and coupling to a specific phospholipase C. Inositol trisphosphate, transiently produced, induces a rapid release of Ca2+ from intracellular stores. Diacylglycerol activates protein kinase C, which, together with calcium, is responsible for steroid secretion. The early events of AVP action are mediated by two types of G-proteins. One is coupled to phospholipase C, and insensitive to pertussis toxin (probably Gq/11) and a second one, which is inactivated by pertussis toxin (Gi protein), is involved in the stimulation of calcium influx. This Ca2+ influx pathway is very important, as no steroidogenic effect of AVP could be observed when experiments were performed in a calcium-free medium or in pertussis toxin-treated cells. Besides the pituitary, the adrenal is also a source for AVP production. Indeed, AVP is synthesized and secreted by chromaffin cells either present in the medulla or scattered throughout the cortex with a more prominent concentration in zona glomerulosa. AVP receptors are also present on chromaffin cells. However, in contrast to AVP receptors in the cortex, these mainly belong to the V1 b subtype, although V1 a receptors are also detected. The results summarized in this review conclusively indicate that AVP is one of the regulators of both cortex and medulla, an influence which may be mediated in part via pituitary AVP and in part via local production of AVP.

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Section: Adrenalsteroid Secretionmentioning

confidence: 86%

Regulation of Adrenocortical Function by Vasopressin

Gallo‐Payet

Guillon

1998

Horm Metab Res

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“…In semiaquatic species, AVT also increases tubular reabsorption (Sawyer 1951(Sawyer , 1957. In addition, AVT appears to indirectly regulate urine output and ion excretion in amphibians, by stimulating aldosterone secretion from the interrenal glands (Iwamuro et al 1991).…”

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confidence: 99%

Development of arginine vasotocin innervation in two species of anuran amphibian:Rana catesbeiana andRana sylvatica

1996

Histochem Cell Biol

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Arginine vasotocin (AVT) is a neurotransmitter in the amphibian central nervous system and is released from the neurohypophysis in the regulation of hydromineral balance and other homeostatic functions. Many amphibians experience drastic changes in habitat with respect to water availability during their transformation from aquatic larvae to terrestrial adults. To examine whether metamorphosis is accompanied by a reorganization of central vasotocinergic neurons, the developmental organization of vasotocin neurons and nerve fibers was studied with immunocytochemistry in the brains of bullfrogs (Rana catesbeiana) and woodfrogs (R. sylvatica). In bullfrogs, early limb-bud-stage tadpoles had AVT-immunoreactive neurons and nerve fibers in the lateral septal nucleus, amygdala, preoptic hypothalamus, suprachiasmatic nucleus, and posterodorsal tegmentum. Woodfrog larvae showed similar patterns of hypothalamic AVT immunoreactivity, although neuronal staining in the amygdala did not appear until metamorphic climax, and never appeared in septal neurons or in the posterodorsal tegmentum. Whereas the highly terrestrial R. sylvatica adults must adapt to an adult habitat with prolonged periods of dehydration, R. catesbeiana adults remain semiaquatic and, as such, need not develop extreme mechanisms for water retention. Nonetheless, vasotocinergic pathways showed developmental similarities in the two species. The early appearance of AVT innervation in both Rana suggests that AVT has neuroregulatory functions well before metamorphosis.

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“…It is also probable that, during metamorphosis, not only ACTH but also some other stimulants are involved in corticoid secretion by the adrenal glands. It is well known that arginine vasotosin (AVT) and its related peptides possess corticoid-releasing activity in several anurans (Iwamuro et al, 1989(Iwamuro et al, , 1991(Iwamuro et al, , 1992Lacher et al, 1989Lacher et al, , 1992Kloas and Hanke, 1990). However, no information about the plasma and pituitary AVT levels and hypothalamic AVT mRNA levels of metamorphosing tadpoles is available.…”

Section: Discussionmentioning

confidence: 99%