Bilateral adrenal enucleation-induced changes in adenohypophyseal pro-opiomelanocortin (POMC)-related peptides synthesis and secretion: A comparative study with adrenalectomized rats

PERONE, MJ; CHISARI, AN; GOMEZ DUMM, CI; SPINEDI, E; ESTIVARIZ, FE

JOURNAL OF ENDOCRINOLOGICAL INVESTIGATION

EDITRICE KURTIS S R L

Año: 1997

0391-4097

The aim of the present study was toelucidate the modulatory effect of transient changesin endogenous glucocorticoids, occurring after bilateraladrenal enucleation (ENUC), on anterior pituitary(AP) proopiomelanocortin (POMC)-derivedpeptides synthesis and output in rats. For this purpose,adult female rats were either bilaterally ENUC,adrenalelectomized (ADX), or sham-operated(SHAM) and killed by decapitation 2,7, 14, and 21days after surgery. Trunk blood was collected formeasurements of ACTH, ~-endorphin (~-END) andcorticosterone (8) concentrations; APs were quicklydissected for the determination of ACTH, ~-endorphin(~-END)-like (~-END-Ll) and Y3-MSH contentsand adrenal glands were removed and submittedto histological study. The results indicate thatENUC and ADX increased AP POMC-related peptidessynthesis and release in association withchanges in the AP processing of peptides belongingto the N-terminal (Y3-MSH), mid (ACTH) and C-terminal(~-LPH/ENDs) portions of POMC. While ADXabolished plasma 8 levels, ENUC induced a transient(day 2) decrease in plasma 8 concentrationswhich returned to SHAM levels at 7 days aftersurgery. These data tallied with the histological observationscarried out, indicating a time-dependentregenerative process of the adrenal which was completedby three weeks after ENUC. There was a differentpattern in plasma ACTH and ~-END levelsbetween ENUC and ADX; maximal plasma peptidelevels were found 7-14 days after ENUC, then fallingdown to SHAM values at 21 days post ENUC.