Regulation of fluid secretion. Stimulates primary urine secretion by Malpighian tubules and causes a dose-dependent stimulation of cAMP levels in the tubules. Has a nonselective effect on Na(+)/K(+) ion transport. In vitro, primarily elevates intracellular Ca(2+). Has synergistic effects with the larger diuretic hormone DH(46) which co-occurs with it. Belongs to the diuretic hormone class 2 family.