Rose R, Fadem B H
School of Zoology, University of Tasmania, Hobart, Tasmania, 7001, Australia.
Horm Behav. 2000 Mar;37(2):163-7. doi: 10.1006/hbeh.1999.1568.
In all major groups of Australian marsupials, prostaglandin F2alpha (PGF) or oxytocin injection initiates birth behavior in adult females, adult males and pouch young. Because inhibitors of PGF synthesis block this initiation, oxytocin may activate birth behavior via the stimulation of PGF synthesis. In this study, the role of PGF and oxytocin in the activation of birth behavior was examined in an American marsupial, the gray short-tailed opossum (Monodelphis domestica). Adult male and female gray opossums were given PGF, oxytocin, or saline (control) before behavioral observation. On the next day, the animals in the oxytocin group were injected with the PGF inhibitor flunixin meglumide (Finadyne, Schering Corp., U.S.A.) before oxytocin reinjection and behavioral observation. Both males and females showed birth behavior in response to PGF but only females responded to oxytocin. There was no significant difference in the latency of response of females to oxytocin alone versus response to oxytocin after receipt of the PGF inhibitor. These results suggest that, in contrast to Australian species, in this American marsupial, oxytocin initiates birth behavior only in females and does not operate via stimulation of prostaglandin secretion.
在澳大利亚有袋类动物的所有主要群体中，注射前列腺素F2α（PGF）或催产素会引发成年雌性、成年雄性和育儿袋幼崽的分娩行为。由于PGF合成抑制剂会阻断这种引发作用，催产素可能通过刺激PGF合成来激活分娩行为。在本研究中，对一种美洲有袋动物——灰短尾负鼠（Monodelphis domestica）中PGF和催产素在激活分娩行为中的作用进行了研究。在行为观察前，给成年雄性和雌性灰负鼠注射PGF、催产素或生理盐水（对照）。第二天，在再次注射催产素和进行行为观察前，给催产素组的动物注射PGF抑制剂氟尼辛葡甲胺（Finadyne，美国先灵公司）。雄性和雌性对PGF均表现出分娩行为，但只有雌性对催产素产生反应。雌性单独对催产素的反应潜伏期与接受PGF抑制剂后对催产素的反应潜伏期之间没有显著差异。这些结果表明，与澳大利亚物种不同，在这种美洲有袋动物中，催产素仅在雌性中引发分娩行为，且不是通过刺激前列腺素分泌来起作用。
