Relaxin Inhibits Central Angiotensin II Expression in Killifish: A Central Osmoregulatory Role for Relaxin and Angiotensin II in the Killifish Fundulus heteroclitus
Abstract: We investigated whether relaxin and brain angiotensin II (AII) are osmoregulatory hormones in killifish. Four groups of killifish acclimatized to different saline environments (freshwater, 25% sea water, 50% sea water [brackish], and sea water) were euthanized and their brains were embedded in paraffin. A separate group of brackish water killifish were injected with relaxin 1 h before dissection and embedding. Serial sagittal sections were immunohistochemically stained for AII. Angiotensin II immunostaining did not differ between saline environments. Contrary to expectation, relaxin decreased the number of AII-immunoreactive cells in hypothalami of brackish water fish.
relaxin angiotensin ii killifish osmoregulation