title: Effect of glucose administration during the estrous cycle on serum hormone profiles, mRNA for steroidogenic enzymes, and breeding performance of ewes.
abstract: Thirty mature Debouillet ewes were used to examine effects of exogenous glucose on endocrine, ovarian, and reproductive responses. Treatments were administered from d 5 through 15 of a normal estrous cycle (d 0 = estrus). Fifteen ewes received daily i.p. injections containing 100 mL of saline (.9%, control), and 15 ewes received daily i.p. injections containing 50 g of glucose (100 mL of 50% dextrose). Ovaries were removed from five ewes per group on d 15, and luteal mRNA encoding steroidogenic enzymes and follicular fluid progesterone (P4) were determined. Serum glucose in treated ewes increased rapidly after injection and remained elevated (P < .01) for 4 h after treatment on d 10 and 14 compared with control values. Serum insulin concentration was also greater (P < .01) after glucose treatment on d 10 and 14, but serum growth hormone concentration was similar (P > .10) in both groups on these days. Serum LH concentration and pulsatility were not altered by glucose injection (P > .15). Serum P4 remained elevated longer (P < .05) during the estrous cycle in treated than in control ewes. Corpora lutea from treated ewes also had more (P < .10) mRNA encoding for cytochrome P450 side-chain cleavage enzyme, but mRNA for 3 beta-hydroxysteriod dehydrogenase/delta 5- delta 4 isomerase and follicular fluid P4 were similar (P > .40) between groups. Glucose-treated ewes conceived later (P < .10) and produced fewer lambs (P < .10) than did controls. These data indicate that exogenous glucose and(or) the subsequent increased serum insulin resulted in ovarian changes associated with elevated luteal P4 production.
authors.affiliation: Department of Animal and Range Sciences, New Mexico State University, Las Cruces 88003, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Rubio
authors.forename: D M
authors.initials: DM
authors.lastname: Hallford
authors.forename: D E
authors.initials: DE
authors.lastname: Hawkins
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000032:analysis / Q000235:genetics*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D015152:Blotting, Northern / Q000379:methods / Q000662:veterinary; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000032:analysis / Q000235:genetics*; D003338:Corpus Luteum / Q000737:chemistry; D004971:Estrus / Q000187:drug effects* / Q000502:physiology; D005260:Female; D015571:Follicular Fluid / Q000737:chemistry; D005947:Glucose / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D011863:Radioimmunoassay / Q000379:methods / Q000662:veterinary; D012756:Sheep / Q000097:blood / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D011374:Progesterone; D007986:Luteinizing Hormone; D013006:Growth Hormone; D015096:3-Hydroxysteroid Dehydrogenases; D002786:Cholesterol Side-Chain Cleavage Enzyme; D005947:Glucose