Physiologic and pharmacologic studies on the motility of isolated guinea pig ovaries

The spontaneous motility of ovaries isolated from guinea pigs in early and late proestrus and estrus was explored. The influences of oxytocin, prostaglandin F2alpha (PGF2alpha), and adrenergic agonists and antagonists were also studied. Spontaneous ovarian isometric developed tension (IDT) and rate of contractions (RC) were greater in late proestrus than in early proestrus or estrus. Furthermore, in late proestrus, oxytocin and PGF2alpha induced ovarian motilities of comparable magnitude and significantly greater than those elicited in other stages of the cycle. Norepinephrine and phenylephrine either failed to alter or inhibited IDT and RC of ovaries in estrus, but stimulated motility in the presence of propranolol. The depressive influence of norephinephrine upon the IDT of ovaries in early proestrus was not seen in late proestrus, when the neurotransmitter was clearly stimulating. The hormonal status of guinea pigs seems to influence spontaneous ovarian motility as well as pharmacologic reactivity to several agents, including those presumably acting upon alpha- and beta-adrenergic receptors.