Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2003-9-12
pubmed:abstractText
Previous observations from this laboratory indicated that horses with high BCS could have resting plasma leptin concentrations ranging from low (1 to 5 ng/mL) to very high (10 to 50 ng/mL). To study the possible interactions of leptin secretion with other endocrine systems, BCS and plasma leptin concentrations were measured on 36 mares and 18 geldings. From mares and geldings that had a mean BCS of at least 7.5, five with the lowest (low leptin) and five with the highest (high leptin) leptin concentrations were selected. Jugular blood samples were collected twice daily for 3 d from the 20 selected horses to determine average resting hormone concentrations. Over the next 12 d, glucose infusion, injection of thyrotropin-releasing hormone (TRH), exercise, and dexamethasone treatment were used to perturb various hormonal systems. By design, horses selected for high leptin had greater (P < 0.0001) leptin concentrations than horses selected for low leptin (14.1 vs. 2.8 +/- 0.92 ng/mL, respectively). In addition, mares had greater (P = 0.008) leptin concentrations than geldings. Horses selected for high leptin had lower (P = 0.027) concentrations of GH but higher (P = 0.0005) concentrations of insulin and thriiodothyronine (T3) than those selected for low leptin. Mares had greater (P = 0.0006) concentrations of cortisol than geldings. There was no difference (P > 0.10) in concentrations of IGF-1, prolactin, or thyroid-stimulating hormone (TSH). Horses selected for high leptin had a greater (P = 0.0365) insulin response to i.v. glucose infusion than horses selected for low leptin. Mares had a greater (P = 0.0006) TSH response and tended (P = 0.088) to have a greater prolactin response to TRH than geldings; the T3 response was greater (P = 0.047) in horses selected for high leptin. The leptin (P = 0.0057), insulin (P < 0.0001), and glucose (P = 0.0063) responses to dexamethasone were greater in horses selected for high leptin than in those selected for low leptin. In addition, mares had a greater (P < 0.0001) glucose response to dexamethasone than geldings. Cortisol concentrations were decreased (P = 0.029) by dexamethasone equally in all groups. In conclusion, differences in insulin, T3, and GH associated with high vs. low leptin concentrations indicate a likely interaction of these systems with leptin secretion in horses and serve as a starting point for future study of the cause-and-effect nature of the interactions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-8812
pubmed:author
pubmed:issnType
Print
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2311-21
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed-meshheading:12968707-Animals, pubmed-meshheading:12968707-Blood Glucose, pubmed-meshheading:12968707-Body Composition, pubmed-meshheading:12968707-Body Constitution, pubmed-meshheading:12968707-Dexamethasone, pubmed-meshheading:12968707-Endocrine Glands, pubmed-meshheading:12968707-Female, pubmed-meshheading:12968707-Glucose, pubmed-meshheading:12968707-Growth Hormone, pubmed-meshheading:12968707-Horses, pubmed-meshheading:12968707-Hydrocortisone, pubmed-meshheading:12968707-Insulin, pubmed-meshheading:12968707-Leptin, pubmed-meshheading:12968707-Male, pubmed-meshheading:12968707-Physical Conditioning, Animal, pubmed-meshheading:12968707-Prolactin, pubmed-meshheading:12968707-Sex Factors, pubmed-meshheading:12968707-Thyrotropin, pubmed-meshheading:12968707-Thyrotropin-Releasing Hormone, pubmed-meshheading:12968707-Thyroxine, pubmed-meshheading:12968707-Time Factors, pubmed-meshheading:12968707-Triiodothyronine
pubmed:year
2003
pubmed:articleTitle
Endocrine responses in mares and geldings with high body condition scores grouped by high vs. low resting leptin concentrations.
pubmed:affiliation
Department of Animal Sciences, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.
pubmed:publicationType
Journal Article