EFFECTS OF IONS AND BIOACTIVE SUBSTANCES ON OVARIAN CONTRACTION IN FUNDULUS-HETEROCLITUS

The effects of potassium, calcium, angiotensin II, urotensin II, melat onin, gonadotropin releasing hormone analogue (GnRH-a), and human chor ionic gonadotropin (hCG) on in vitro ovarian smooth muscle contraction were observed in Fundulus heteroclitus. Calcium induced contractions and modified spontaneous contractions in a dose-dependent manner. Pota ssium, angiotensin II and urotension II induced dose-dependent contrac tions while melatonin, GnRH-a and HCG had no observable effect on the system. These data highlight the integral role of calicum in ovarian c ontraction and suggest possible roles in reproduction for angiotensin II and urotensin II. (C) 1993 Wiley-Liss, Inc.