Disturbance of the reproductive axis induced by negative energy balance
| Autor: | Stephen J. Judd |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Leptin
endocrine system medicine.medical_specialty Hypothalamus Reproductive technology Biology Feedback Endocrinology Internal medicine Genetics medicine Humans Molecular Biology Reproduction Proteins Neuropeptide Y receptor Adipose Tissue Reproductive Medicine Female Animal Science and Zoology Animal studies Energy Metabolism Food Deprivation Luteinizing hormone hormones hormone substitutes and hormone antagonists Homeostasis Developmental Biology Biotechnology Hormone |
| Zdroj: | Reproduction, Fertility and Development. 10:65 |
| ISSN: | 1031-3613 |
| DOI: | 10.1071/r98024 |
| Popis: | Animal reproduction is impaired when intake of energy is so restricted that activities essential to life are threatened; this is seen as a homeostatic adjustment that restricts wasteful energy expenditure. Fasting or exercising to a degree requiring considerable energy expenditure has major effects on the hypothalamus, including activation of corticotrophin-releasing factor (CRF) neurons, suppression of thyrotrophin-releasing hormone synthesis, and increased growth hormone secretion; these are associated with increased concentrations of hypothalamic neuropeptide Y mRNA and are corrected by administration of leptin, an adipose-tissue protein with a tertiary structure similar to the cytokine interleukin-2. This response to fasting results from a disordered pattern of activity in the gonadotrophin-releasing hormone (GnRH) pacemaker, characterized by reduced luteinizing hormone pulsatility, particularly during daytime. Animal studies have suggested that the response depends on an intact afferent vagal system from the stomach and the presence of oestrogen. Noradrenergic neurons forming the A2 group increase the activity of CRF neurons that, in turn, inhibit GnRH pulsatility. Reproductive impairment due to fasting is reversed by leptin, and abnormalities of leptin are described in individuals who fast or who develop exercise-induced amenorrhoea. This paper discusses these changes induced by negative energy balance and speculates on the involvement of leptin as a contributor to these abnormalities. |
| Databáze: | OpenAIRE |
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