title: Dietary melatonin alters uterine artery hemodynamics in pregnant Holstein heifers.
abstract: The objective was to examine uterine artery hemodynamics and maternal serum profiles in pregnant heifers supplemented with dietary melatonin (MEL) or no supplementation (CON). In addition, melatonin receptor-mediated responses in steroid metabolism were examined using a bovine endometrial epithelial culture system. Twenty singleton pregnant Holstein heifers were supplemented with 20 mg of melatonin (n = 10) or no melatonin supplementation (control; n = 10) from days 190 to 262 of gestation. Maternal measurements were recorded on days 180 (baseline), 210, 240, and 262 of gestation. Total uterine blood flow was increased by 25% in the MEL-treated heifers compared with the CON. Concentrations of progesterone were decreased in MEL vs CON heifers. Total serum antioxidant capacity was increased by 43% in MEL-treated heifers when compared with CON. Activity of cytochrome P450 1A, 2C, and superoxide dismutase was increased in bovine endometrial epithelial cells treated with melatonin, whereas the melatonin receptor antagonist, luzindole, negated the increase in cytochrome P450 2C activity. Moreover, estradiol or progesterone treatment altered bovine uterine melatonin receptor expression, which could potentiate the melatonin-mediated responses during late gestation. The observed increase in total uterine blood flow during melatonin supplementation could be related to its antioxidant properties. Compromised pregnancies are typically accompanied by increased oxidative stress; therefore, melatonin could serve as a therapeutic supplementation strategy. This could lead to further fetal programming implications in conjunction with offspring growth and development postnatally.
authors.affiliation: Department of Animal and Dairy Sciences, Mississippi State University, Mississippi, MS, 39762, USA.
authors.forename: K E
authors.initials: KE
authors.lastname: Brockus
authors.affiliation: Department of Animal and Dairy Sciences, Mississippi State University, Mississippi, MS, 39762, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: Hart
authors.affiliation: Department of Animal and Dairy Sciences, Mississippi State University, Mississippi, MS, 39762, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Gilfeather
authors.affiliation: Department of Animal and Dairy Sciences, Mississippi State University, Mississippi, MS, 39762, USA.
authors.forename: B O
authors.initials: BO
authors.lastname: Fleming
authors.affiliation: Department of Animal and Dairy Sciences, Mississippi State University, Mississippi, MS, 39762, USA. Electronic address: clemley@ads.msstate.edu.
authors.forename: C O
authors.initials: CO
authors.lastname: Lemley
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D002417:Cattle / Q000097:blood / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D005260:Female; D006439:Hemodynamics; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D011247:Pregnancy; D055988:Uterine Artery / Q000187:drug effects* / Q000502:physiology; D014599:Uterus / Q000098:blood supply*
chemical_list: D008550:Melatonin
keywords: Antioxidant; Dairy cow; Melatonin; Pregnancy; Uterine artery