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Leptin-mediated effects of undernutrition or fasting on luteinizing hormone and growth hormone secretion in ovariectomized ewes depend on the duration of metabolic perturbation.
J Neuroendocrinol 2004; 16(3):244-55JN

Abstract

We aimed to determine the importance of leptin in the regulation of luteinizing hormone (LH) and growth hormone (GH) secretion in ovariectomized (OVX) ewes. Lean and fat sheep were produced by dietary manipulation over 8 months and were then fasted for 32 h. Plasma concentrations of glucose, insulin and leptin were higher in the fat group. Fasting decreased plasma concentrations of glucose and insulin and increased concentrations of nonesterified fatty acids (NEFA) in fat and lean ewes, but leptin concentrations were reduced in the fat group only. Plasma GH concentrations were higher in the lean group and LH concentrations were lower; there was no effect of fasting. These data suggested that long-term changes in plasma leptin concentrations might affect LH and GH secretion, but acute changes with fasting had no effect. OVX ewes of normal body weight were fasted for 72 h with or without intracerebroventricular (i.c.v.) infusion of leptin (4 microg/h), achieving similar metabolic effects to the 32 h fast. The 72-h fast increased LH pulse amplitude, mean GH and cortisol concentrations, but these changes were corrected towards normal by leptin treatment. Thus, leptin could attenuate fasting-induced alterations in the secretion of LH, GH and cortisol. Finally, we food-restricted OVX ewes for 4 months (lean), leading to a 20-kg reduction in body weight. Plasma concentrations of leptin and insulin were decreased, and plasma GH concentrations increased, but there was no effect on plasma concentrations of LH, glucose or NEFA. Icv infusion of leptin did not affect any endocrine or metabolic parameter in these ewes. In summary, maintenance of a lean or fat condition for a prolonged period (8 months) or an extended fasting (72 h) can affect LH and GH secretion, but short-term food restriction (4 months) affected only GH secretion and short-term fasting (32 h) had no effect on either LH or GH secretion. This is in spite of altered plasma leptin concentrations in all circumstances studied. Although leptin treatment can restore plasma concentrations of LH, GH and cortisol towards normal in sheep fasted for 72 h, some other factor(s) must signal to the brain to cause shifts in neuroendocrine function in other conditions where nutritional/metabolic status is altered.

Authors+Show Affiliations

Prince Henry's Institute of Medical Research, Clayton, Victoria, Australia. Belinda.Henry@bristol.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15049855

Citation

Henry, B A., et al. "Leptin-mediated Effects of Undernutrition or Fasting On Luteinizing Hormone and Growth Hormone Secretion in Ovariectomized Ewes Depend On the Duration of Metabolic Perturbation." Journal of Neuroendocrinology, vol. 16, no. 3, 2004, pp. 244-55.
Henry BA, Goding JW, Tilbrook AJ, et al. Leptin-mediated effects of undernutrition or fasting on luteinizing hormone and growth hormone secretion in ovariectomized ewes depend on the duration of metabolic perturbation. J Neuroendocrinol. 2004;16(3):244-55.
Henry, B. A., Goding, J. W., Tilbrook, A. J., Dunshea, F. R., Blache, D., & Clarke, I. J. (2004). Leptin-mediated effects of undernutrition or fasting on luteinizing hormone and growth hormone secretion in ovariectomized ewes depend on the duration of metabolic perturbation. Journal of Neuroendocrinology, 16(3), pp. 244-55.
Henry BA, et al. Leptin-mediated Effects of Undernutrition or Fasting On Luteinizing Hormone and Growth Hormone Secretion in Ovariectomized Ewes Depend On the Duration of Metabolic Perturbation. J Neuroendocrinol. 2004;16(3):244-55. PubMed PMID: 15049855.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Leptin-mediated effects of undernutrition or fasting on luteinizing hormone and growth hormone secretion in ovariectomized ewes depend on the duration of metabolic perturbation. AU - Henry,B A, AU - Goding,J W, AU - Tilbrook,A J, AU - Dunshea,F R, AU - Blache,D, AU - Clarke,I J, PY - 2004/3/31/pubmed PY - 2004/6/16/medline PY - 2004/3/31/entrez SP - 244 EP - 55 JF - Journal of neuroendocrinology JO - J. Neuroendocrinol. VL - 16 IS - 3 N2 - We aimed to determine the importance of leptin in the regulation of luteinizing hormone (LH) and growth hormone (GH) secretion in ovariectomized (OVX) ewes. Lean and fat sheep were produced by dietary manipulation over 8 months and were then fasted for 32 h. Plasma concentrations of glucose, insulin and leptin were higher in the fat group. Fasting decreased plasma concentrations of glucose and insulin and increased concentrations of nonesterified fatty acids (NEFA) in fat and lean ewes, but leptin concentrations were reduced in the fat group only. Plasma GH concentrations were higher in the lean group and LH concentrations were lower; there was no effect of fasting. These data suggested that long-term changes in plasma leptin concentrations might affect LH and GH secretion, but acute changes with fasting had no effect. OVX ewes of normal body weight were fasted for 72 h with or without intracerebroventricular (i.c.v.) infusion of leptin (4 microg/h), achieving similar metabolic effects to the 32 h fast. The 72-h fast increased LH pulse amplitude, mean GH and cortisol concentrations, but these changes were corrected towards normal by leptin treatment. Thus, leptin could attenuate fasting-induced alterations in the secretion of LH, GH and cortisol. Finally, we food-restricted OVX ewes for 4 months (lean), leading to a 20-kg reduction in body weight. Plasma concentrations of leptin and insulin were decreased, and plasma GH concentrations increased, but there was no effect on plasma concentrations of LH, glucose or NEFA. Icv infusion of leptin did not affect any endocrine or metabolic parameter in these ewes. In summary, maintenance of a lean or fat condition for a prolonged period (8 months) or an extended fasting (72 h) can affect LH and GH secretion, but short-term food restriction (4 months) affected only GH secretion and short-term fasting (32 h) had no effect on either LH or GH secretion. This is in spite of altered plasma leptin concentrations in all circumstances studied. Although leptin treatment can restore plasma concentrations of LH, GH and cortisol towards normal in sheep fasted for 72 h, some other factor(s) must signal to the brain to cause shifts in neuroendocrine function in other conditions where nutritional/metabolic status is altered. SN - 0953-8194 UR - https://www.unboundmedicine.com/medline/citation/15049855/Leptin_mediated_effects_of_undernutrition_or_fasting_on_luteinizing_hormone_and_growth_hormone_secretion_in_ovariectomized_ewes_depend_on_the_duration_of_metabolic_perturbation_ L2 - https://doi.org/10.1111/j.0953-8194.2004.01157.x DB - PRIME DP - Unbound Medicine ER -