Effects of pineal-derived indolic compounds and of certain neuropeptides on the growth processes in the thyroid gland.
Thyroidology
; 4(1): 11-5, 1992 Apr.
Article
em En
| MEDLINE
| ID: mdl-1284326
ABSTRACT
The aim of the present study was to examine the effects of melatonin (Mel) and of pinealectomy (PX) [in a long-term experiment in vivo - 10 weeks], as well as of Mel and N-acetylserotonin (NAc-5HT) [in experiments ex vivo in vitro and in vitro], on the rat thyroid growth processes. Additionally, the incubations in vitro of rat thyroid lobes with 3H-thymidine, in the presence of TSH, vasoactive intestinal polypeptide (VIP), VIP-antagonist ([4Cl-D-Ph6, Leu17]VIP), somatostatin (SS), all the substances used separately or jointly in combinations, were performed. It was shown that (a) Mel--administered in late afternoon injections--decreased, while PX increased examined indices of thyroid growth in vivo, (b) Mel--administered in s.c. implanted pellets--reversed the inhibitory effect of Mel injections, (c) in experiments ex vivo in vitro and in vitro, the inhibitory effect of Mel revealed only for the lowest applied dose/concentration of the hormone, (d) NAc-5HT showed no effect, (e) VIP decreased 3H-thymidine incorporation into DNA of thyroid lobes in vitro and enhanced the inhibitory effect of SS on the process in question, (f) VIP-antagonist failed to reverse the inhibitory action of VIP on the thyroid growth.
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Base de dados:
MEDLINE
Assunto principal:
Glândula Pineal
/
Glândula Tireoide
/
Neuropeptídeos
/
Indóis
Limite:
Animals
Idioma:
En
Ano de publicação:
1992
Tipo de documento:
Article