PGE receptor characteristics on porcine luteal cells during
the estrous cycle and early pregnancy
S.-M. Feng, G.W. Almond*
Department of Food Animal and Equine Medicine, College of Veterinary Medicine, North Carolina State
University, 4700 Hillsborough Street, Raleigh, NC 27606, USA
Received 24 December 1997; received in revised form 14 August 1998
Abstract
This study examined the affinities and concentrations of prostaglandin E (PGE) receptors on
porcine luteal cells during the estrous cycle and early pregnancy. Corpora lutea (CL) were
obtained from nonpregnant gilts at days 9 (n = 4), 12 (n = 3), and 14 (n = 6); three gilts
possessed red, vascular CL and three gilts had white nonvascular CL) of the estrous cycle, and
days 9 (n = 4), 12 (n = 3), 14 (n = 5), and 30 (n = 5) of pregnancy. The CL were dissociated
enzymatically to disperse single cells and the red blood cells were removed by elutriation. The
luteal cells were assayed for specific PGE binding by displacement analysis with use of [
3
H] PGE
2
and varying concentrations of unlabeled PGE
2
. The specific binding of [
3
H] PGE
2
to luteal cells
decreased (p 0.05) from days 9 to 14 of the estrous cycle, but only decreased (p 0.05) from
days 9 to 12 of pregnancy. Specific binding was higher (p 0.05) on day 14 of pregnancy than
the comparable stage of the estrous cycle. The affinities of PGE receptors decreased (p 0.05)
only on the luteal cells dissociated from red, vascular CL of day 14 nonpregnant gilts compared
with those of other days of the estrous cycle and pregnancy. The number of PGE receptors on
porcine luteal cells was similar (p 0.05) in pregnant and nonpregnant gilts, but decreased (p
0.05) on days 12–14 postestrus. During early pregnancy, it was evident that high affinity PGE
receptors are sustained on porcine luteal cells; however, the role of the PGE receptors in maternal
recognition of pregnancy remains speculative. © 1999 Elsevier Science Inc. All rights reserved.
Keywords: Pig; Corpus luteum; Prostaglandin E; Receptors; Luteal cells
* Corresponding author. Tel.: +1-919-829-4240; fax: +1-919-829-4464.
Prostaglandins & other Lipid Mediators 57 (1999) 13–22
0090-6980/99/$ – see front matter © 1999 Elsevier Science Inc. All rights reserved.
PII: S0090-6980(98)00067-7