Mechanisms of ACTH- and angiotensin II-stimulated 1 alpha-hydroxycorticosterone secretion in the dogfish, Scyliorhinus canicula.
An isolated perifused interrenal gland preparation from the lesser-spotted dogfish, Scyliorhinus canicula, was used to investigate the mechanisms of action of ACTH and angiotensin II (AII) on elasmobranch adrenocortical cells. ACTH-stimulated 1 alpha-hydroxycorticosterone secretion was unaffected by dantrolene and significantly decreased in the absence of extracellular calcium. Dibutyryl cyclic AMP produced a dose-dependent increase in 1 alpha-hydroxycorticosterone secretion. The results suggest that the mechanism of ACTH action in elasmobranchs may be similar to that reported for mammals and amphibians, involving the synergistic action of calcium with the cyclic AMP messenger system. AII-stimulated 1 alpha-hydroxycorticosterone secretion was significantly inhibited in the presence of dantrolene and in the absence of extracellular calcium, indicating that both extracellular and intracellular calcium are required for the full action of AII. These results are consistent with results in mammals and amphibians where AII stimulates phosphatidylinositol 4,5-bisphosphate hydrolysis and changes in intracellular calcium concentration, and they suggest that AII may operate via this mechanism to stimulate 1 alpha-hydroxycorticosterone secretion in elasmobranchs.
Gatty Marine Laboratory, University of St Andrews, East Sands, Fife, UK.
K J
KJ
Armour
L B
LB
O'Toole
N
N
Hazon
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D003345:Corticosterone / Q000031:analogs & derivatives* / Q000378:metabolism; D003620:Dantrolene / Q000494:pharmacology; D004284:Dogfish / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D007401:Interrenal Gland / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010477:Perfusion
C002529:1 alpha-hydroxycorticosterone; D000804:Angiotensin II; D000001:Calcimycin; D003994:Bucladesine; D000324:Adrenocorticotropic Hormone; D003620:Dantrolene; D002118:Calcium; D003345:Corticosterone