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The existence of independent control mechanisms of beta-endorphin (beta-EP) secretion from the anterior (AP) and intermediate (NIL) pituitary lobes is now ascertained. The aim of this study was to evaluate the effect of surgical separation from the hypothalamus of the two pituitary lobes on beta-EP secretion. Two experimental models of surgical hypothalamo-pituitary disconnection were used: 1) rats with ablation of the medial basal hypothalamus (MBH); 2) rats bearing two entire ectopic pituitaries or two anterior pituitaries (APs) only, transplanted under the kidney capsule. In rats with MBH-ablation plasma beta-EP levels were significantly higher than in sham-operated controls. Plasma beta-EP levels increased in rats transplanted with entire pituitaries 3 days after surgery and were still elevated after 1 week. In rats transplanted with APs only, no significant beta-EP changes in plasma were evident. In both experimental conditions no significant difference was present in beta-LPH plasma levels. Concentrations of beta-EP in the ectopic NILs decreased gradually after transplantation. In all these results indicate that that NIL but not the AP is capable, when is disconnected from the hypothalamus, or secreting autonomously beta-EP.
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V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
January 1986,
Endocrinology,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
August 1984,
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F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
January 1997,
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F Petraglia, and
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A Penalva, and
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D Cocchi
January 1985,
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F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
August 1985,
Neuroscience letters,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
June 1984,
Endocrinology,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
June 1981,
The Journal of neuroscience : the official journal of the Society for Neuroscience,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
January 1983,
Peptides,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
October 1990,
Neuropeptides,
F Petraglia, and
V Locatelli, and
A Penalva, and
S G Cella, and
A R Genazzani, and
D Cocchi
December 1994,
The Anatomical record,
