Hj. Mcmillan et Ke. Wynne-edwards, Divergent reproductive endocrinology of the estrous cycle and pregnancy indwarf hamsters (Phodopus), COMP BIOC A, 124(1), 1999, pp. 53-67
Citations number
71
Categorie Soggetti
Animal Sciences",Physiology
Journal title
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY
Progesterone (P4) and prolactin (PRL) in peripheral circulation of Siberian
hamsters (Phodopus sungorus) throughout an estrous cycle and pregnancy wer
e determined by repeated, small volume sampling from individuals housed in
modified home cages. As predicted, the endocrinology of P. sungorus reprodu
ction is similar to the rat, mouse and golden hamster and shows none of the
eight distinctive features known for Djungarian hamsters (Phodopus campbel
li). Specifically, in P. sungorus there is no evidence for resumption of pi
tuitary PRL surges in late pregnancy, P4 concentrations during the differen
tiation of the: corpus luteum on day 2 of pregnancy are higher las opposed
to lower) than concentrations on the comparable day of an unmated estrous c
ycle (diestrus 1), P4 concentrations increase throughout pregnancy. PRL sur
ges are common during the estrous cycle, including a reliable surge on proe
strus, and P4 plays an important role in facilitating the expression of beh
avioral receptivity. We conclude that 'novel' P, campbelli reproductive end
ocrinology has evolved since a common ancestor was shared with P. sungorus.
With a time frame (the available time since the divergence of the two spec
ies) and an ecological context (known niches and behavior in the wild) thes
e: species offer the opportunity to study endocrinological evolution in pro
gress. (C) 1999 Elsevier Science Inc. All rights reserved.