Abstract
Long-term nutritional background is thought to influence hypothalamic appetite and reproductive neuroendocrine responses to short-term nutritional feedback. In order to investigate this phenomenon, the effects of intracerebroventricular
administration of insulin or neuropeptide-Y (NPY) on LH secretion and voluntary food intake (VFI) were examined in sheep that were initially thin and kept on an increasing nutritional plane (INP), or initially fat and kept on a decreasing nutritional plane (DNP), for 10 weeks. Intracerebroventricular insulin stimulated LH secretion and suppressed VFI in INP sheep when initially thin, but not when they became fat, and had no effect on LH in DNP sheep when initially
fat, and stimulated LH secretion when they became thin. Intracerebroventricular NPY had no effect on LH or VFI in INPsheep when initially thin, decreased LH secretion and increased VFI when they became fat, and decreased LH secretion
in DNP sheep when initially fat but had no effect when they became thin. Therefore, sensitivity to insulin increases with low or decreasing nutritional status and decreases with high or increasing nutritional status, whereas sensitivity to NPY increases with high or increasing nutritional status and decreases with low or decreasing nutritional status. In conclusion, reproductive neuroendocrine and appetite responses to acute changes in nutritional feedback signals depend on the individual’s longer-term nutritional background.
administration of insulin or neuropeptide-Y (NPY) on LH secretion and voluntary food intake (VFI) were examined in sheep that were initially thin and kept on an increasing nutritional plane (INP), or initially fat and kept on a decreasing nutritional plane (DNP), for 10 weeks. Intracerebroventricular insulin stimulated LH secretion and suppressed VFI in INP sheep when initially thin, but not when they became fat, and had no effect on LH in DNP sheep when initially
fat, and stimulated LH secretion when they became thin. Intracerebroventricular NPY had no effect on LH or VFI in INPsheep when initially thin, decreased LH secretion and increased VFI when they became fat, and decreased LH secretion
in DNP sheep when initially fat but had no effect when they became thin. Therefore, sensitivity to insulin increases with low or decreasing nutritional status and decreases with high or increasing nutritional status, whereas sensitivity to NPY increases with high or increasing nutritional status and decreases with low or decreasing nutritional status. In conclusion, reproductive neuroendocrine and appetite responses to acute changes in nutritional feedback signals depend on the individual’s longer-term nutritional background.
Original language | English |
---|---|
Pages (from-to) | 329-338 |
Number of pages | 10 |
Journal | Reproduction, Fertility and Development |
Volume | 23 |
Issue number | 2 |
DOIs | |
Publication status | Published - Jan 2011 |
Keywords
- body fat
- food intake
- GnRH
- hypothalamus
- LH