Abstract #M221
Section: Physiology and Endocrinology
Session: Physiology and Endocrinology: Effects of nutrition and metabolism on ruminant reproduction
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Physiology and Endocrinology: Effects of nutrition and metabolism on ruminant reproduction
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# M221
Ovine maternal nutrient restriction from mid to late gestation induces steroid metabolizing enzyme activity in maternal and fetal reproductive and liver tissues.
Megan P. T. Coleson*1, Christa L. Gilfeather1, Kimberly A. Vonnahme2, Caleb O. Lemley1, 1Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS, 2Department of Animal Sciences, North Dakota State University, Fargo, ND.
Key Words: cytochrome P450, nutrient restriction, steroid
Ovine maternal nutrient restriction from mid to late gestation induces steroid metabolizing enzyme activity in maternal and fetal reproductive and liver tissues.
Megan P. T. Coleson*1, Christa L. Gilfeather1, Kimberly A. Vonnahme2, Caleb O. Lemley1, 1Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS, 2Department of Animal Sciences, North Dakota State University, Fargo, ND.
The objective was to determine the effects of nutrient restriction on steroid metabolizing enzymes within maternal, placental, and fetal tissues. Singleton pregnant ewe lambs (n = 30) were allocated to receive either 100% [adequate (ADQ; n = 14)] or 60% [restricted (RES; n = 16)] of nutrient requirements from d 50 until d 130 of gestation. At slaughter both maternal and fetal livers and maternal (caruncle; CAR) and fetal (cotyledon; COT) placentas were collected for analysis. Activity of cytochrome P450 2C (CYP2C), cytochrome P450 1A (CYP1A), and cytochrome P450 3A (CYP3A), were determined using specific luminogenic substrates. Activities were expressed relative to mg of protein, total tissue weight, or BW. Data were analyzed using MIXED procedure of SAS and the model statement included nutritional plane. Activity of CYP2C was not detected in CAR or COT tissues. Activity of CYP1A and CYP3A were not different in CAR tissue between the 2 treatments. Activity of CYP1A relative to BW was increased (P = 0.03) in COT tissue of RES ewes compared with ADQ fed; however, CYP3A activity in COT was not different between treatments. Maternal liver activity of CYP2C was decreased (P < 0.01) in RES ewes compared with ADQ; however, activity of CYP1A (relative to mg of protein), and CYP3A (relative to mg of protein or maternal BW) were increased (P ≤ 0.05) in RES ewes compared with ADQ. Fetal liver activity of CYP1A (relative to liver weight or fetal BW), CYP2C (relative to liver weight), and CYP3A (relative to mg of protein, liver weight, or fetal BW) were decreased (P < 0.05) in RES ewes compared with ADQ. In conclusion, maternal nutrient restriction increased activity of CYP1A and CYP3A in maternal liver, but decreased the activity of CYP1A and CYP3A in fetal liver. A similar downregulation of CYP2C activity was observed in both maternal and fetal liver. The differential regulation of hepatic cytochrome P450 in maternal and fetal tissues may influence peripheral steroid concentrations during late pregnancy and deserves future investigation.
Key Words: cytochrome P450, nutrient restriction, steroid
