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Pinealectomy impairs adipose tissue adaptability to exercise in rats
Cristina N Borges-Silva1, Maria I C Alonso-Vale, Solange M Franzói-De-Moraes
1Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Journal of Pineal Research
|April 9, 2005
Summary
Pinealectomy impairs rat adipose tissue metabolism, reducing insulin-stimulated glucose uptake. Exercise training benefits intact rats but not pinealectomized ones, highlighting the pineal gland's role in metabolic adaptation.
Area of Science:
- Endocrinology
- Metabolic research
- Adipose tissue biology
Background:
- The pineal gland's role in metabolic regulation is not fully understood.
- Exercise training is known to influence adipose tissue metabolism.
Purpose of the Study:
- To investigate the impact of pinealectomy and exercise training on rat adipose tissue metabolism.
- To determine if pinealectomy affects the adaptive responses of adipocytes to exercise.
Main Methods:
- Adult male Wistar rats underwent pinealectomy (PINX) or sham-operation (CONTROL).
- Rats were subjected to an 8-week exercise training program or remained untrained.
- Peri-epididymal adipocytes were isolated to assess insulin-stimulated glucose uptake, substrate oxidation (glucose, lactate, acetate, palmitate), and insulin binding.
Main Results:
- Pinealectomy significantly decreased insulin-stimulated glucose uptake in adipocytes, independent of insulin binding capacity.
- Exercise training increased baseline glucose uptake in control rats but not in pinealectomized rats.
- Training enhanced glucose and palmitate oxidation while reducing lactate and acetate oxidation in control adipocytes; these adaptations were blunted in pinealectomized rats.
- Pinealectomized rats showed increased palmitate oxidation even without training.
Conclusions:
- The pineal gland plays a crucial role in modulating adipocyte substrate utilization patterns.
- Absence of the pineal gland disrupts the adaptive metabolic responses of adipose tissue to exercise training in rats.