STIMULATION OF PARTURITION IN A VIVIPAROUS LIZARD (SCELOPORUS-JARROVI) BY ARGININE VASOTOCIN

Pregnant, adult female Sceloporus jarrovi were randomly partitioned into three groups. The control subjects received a single intraperitoneal injection (0.1 ml) of 0.75% physiological saline (N = 4), whereas the experimental animals received 0.02 μg AVT/0.1 ml saline (N = 5) or 2.0 μg AVT/0.1 ml saline (N = 5). Several dependent measures of parturition were obtained, including (1) initial contraction latency, measured as the duration from injection to first effective contraction, (2) parturition latency, or the time lapse between injection and first birth, and (3) interbirth duration, representing the period of time between individual births. Neither oviductal contractions nor parturition were observed in saline-treated females, whereas both concentrations of AVT induced parturition in all experimental subjects. No significant differences were indicated between the two AVT groups for initial contraction latency and parturition latency. Mean duration between individual births for the 2.0 and 0.02 μg AVT groups did not differ and were found to be similar to those reported for natural births. © 1979.