Review: Maintenance of the ruminant corpus luteum during pregnancy: interferon-tau and beyond

Milo C Wiltbank; Pedro L J Monteiro; Rafael R Domingues; João Paulo N Andrade; Megan A Mezera

doi:10.1016/j.animal.2023.100827

Review: Maintenance of the ruminant corpus luteum during pregnancy: interferon-tau and beyond

Animal. 2023 May:17 Suppl 1:100827. doi: 10.1016/j.animal.2023.100827.

Authors

Milo C Wiltbank¹, Pedro L J Monteiro², Rafael R Domingues³, João Paulo N Andrade², Megan A Mezera³

Affiliations

¹ Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53706, USA. Electronic address: Wiltbank@wisc.edu.
² Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
³ Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA; Endocrinology and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI 53706, USA.

PMID: 37567676
DOI: 10.1016/j.animal.2023.100827

Abstract

This manuscript reviews the mechanisms that maintain the corpus luteum (CL) of pregnancy in ruminants. In mammals, ovulation and luteinization of the remaining cells in the CL are due to a surge in Luteinizing Hormone (LH). In cattle, continued secretion of pulses of LH is essential for full development and function of the CL during the estrous cycle (LH pulses), however, the few studies on the CL after d20 of pregnancy do not indicate that LH is essential for maintaining the CL of pregnancy. The first essential step in maintaining the CL of pregnancy in ruminants is overcoming the mechanisms that cause regression of the CL in non-pregnant ruminants (d18-25 in cattle; d13-21 in sheep). These mechanisms have a uterine component involving oxytocin-induced prostaglandin F2α (PGF2A) pulses and a luteal component involving decreased progesterone production and luteal cell death. There is a critical role for embryonic interferon-tau (IFNT) in suppressing the uterine secretion of PGF2A during early pregnancy (d13-21 in sheep; d16-25 in cattle) and preventing luteolysis. There are also effects of IFNT on the expression of interferon-stimulated genes in other tissues including the CL but the physiologic role of these interferon-stimulated genes is not yet clear. After the IFNT period, there is another mechanism that maintains the CL of pregnancy in ruminants since embryonic IFNT is inhibited as attachment occurs and trophoblastic binucleate/giant cells begin secretion of pregnancy-associated glycoproteins. The second mechanism for luteal maintenance has not yet been defined but acts in a local manner (ipsilateral to pregnancy), and remains functional from d25 until just before parturition. The most likely mechanisms mediating later maintenance of the CL of pregnancy are increased uterine blood flow or decreased prostaglandin transporter expression in the utero-ovarian vasculature, preventing PGF2A reaching the CL. Finally, implications of these ideas on pregnancy loss in cattle are explored, highlighting the importance of inappropriate regression of the CL of pregnancy as a mechanism for pregnancy loss in cattle.

Keywords: Interferon-stimulated genes; Luteal; Pregnancy loss; Pregnancy-associated glycoproteins; Prostaglandin F2A.

Publication types

Review

MeSH terms

Animals
Cattle
Corpus Luteum*
Dinoprost
Female
Luteinizing Hormone
Luteolysis / metabolism
Ovary
Pregnancy
Progesterone
Ruminants* / physiology
Sheep

Substances

Progesterone
Luteinizing Hormone
Dinoprost