Water-retention effect of suberogorgin was due to secretion of antidiuretic hormone in rat.
AIM
To study the mechanism of antidiuretic effect of suberogorgin (Sub).


METHODS
Conscious rat was given i.g. Sub 3.16 mg.kg-1 20 min after water-loaded treatment and then urine was collected in metabolic cage. Ion excretion was determined in atomic emission spectrometry. Urinary prostaglandin E (PGE), plasma PGE, antidiuretic hormone (ADH), and aldosterone were measured with RIA. Sub vs pituitrin or DOCA effects were carried out in hypophysectomized or adrenalectomized rats.


RESULTS
The urine volume and the excretions of urinary sodium and potassium were decreased, maximally by 91%, 76%, and 86%, during the 24-h period after Sub. This antidiuretic effect possessed a progressive weakening with time. The concentrations of urinary PGE, plasma PGE, and ADH were increased by 25%, 212%, and 538%, respectively, but plasma aldosterone was not significantly influenced, 2 h after Sub dosing. The response of urine-excretion of rat to Sub was almost resisted by hypophysectomy but not by adrenalectomy.


CONCLUSION
Sub decreased the urine excretion by, at least in part, accelerating the secretion of ADH but neither by PGE nor by aldosterone.