Indomethacin influences arginine vasotocin-induced parturition and oviposition in lizards (Sceloporus jarrovi and Sceloporus undulatus ).
The effect of the prostaglandin blocker indomethacin on arginine vasotocin-induced birth was examined. Gravid female, oviparous (Sceloporus undulatus ) and viviparous (Sceloporus jarrovi ) lizards were pretreated with saline or indomethacin, a potent blocker of PG synthesis. Pretreatment was followed by an intraperitoneal injection of AVT. Pretreatment with indomethacin significantly delayed the onset of AVT-induced oviposition in S. undulatus , whereas it had no effect on latency to birth in S. jarrovi . Female S. jarrovi treated with indomethacin, however, gave birth to only part of the total litter, whereas control females gave birth to complete litters. In viviparous females, an interaction of embryonic age with pretreatment was evident; females having more developed embryos decreased birth latency significantly and increased the percentage of parturition when compared with females that had embryos at earlier stages of development. Our data suggest that although exogenous AVT can stimulate oviposition or parturition, these events occur more rapidly and completely when prostaglandin synthesis is not inhibited.
Guillette
L J
LJ
Laboratory of Vertebrate Reproduction Department of Zoology University of Florida Gainesville, FL 32611 USA.
Pfrimmer Hensley
A
A
Matter
J M
JM
Jaffe
P H
PH