Serotonergic involvement in the regulation of prolactin and vasoactive intestinal peptide mRNA expression in the rat anterior pituitary.
5-Hydroxytryptophan/pharmacology; alpha-Methyltyrosine; Animals; Anterior/*chemistry/drug effects/metabolism; Blotting; Bromocriptine/pharmacology; Gene Expression Regulation/drug effects/physiology; Genetic; Haloperidol/pharmacology; Ketanserin/pharmacology; Male; Messenger/*analysis/genetics; Methiothepin/pharmacology; Methoxydimethyltryptamines/pharmacology; Methyltyrosines/pharmacology; Northern; Pituitary Gland; Prolactin/analysis/*genetics/metabolism; Quipazine/pharmacology; Rats; RNA; Serotonin/*physiology; Sprague-Dawley; Time Factors; Transcription; Vasoactive Intestinal Peptide/analysis/*genetics/metabolism
These studies examined the contribution of serotonin (5-HT) to the control of prolactin (PRL) and vasoactive intestinal peptide (VIP) messenger RNA expression in rat anterior pituitary. Daily injection of rats with the biosynthetic precursor to serotonin, 5-hydroxytryptophan (5-HTP; 25 mg/kg, q.i.d.), resulted on day 5 in a 50% increase in the expression of PRL mRNA in the pituitary while at the same time reducing the levels of both the 1.0 and 1.7 kb VIP mRNA transcripts. Co-treatment of rats with 5-HTP plus the catecholamine biosynthesis inhibitor, alpha-methyl-tyrosine (alpha-MT; 150 mg/kg, q.d. x 2 days), or the dopamine receptor antagonist haloperidol (1.25 mg/kg, b.i.d. x 5 days), resulted in increases in pituitary PRL message levels that were greater than those observed with either anti-dopaminergic agent alone. In contrast, 5-HTP was unable to reverse the inhibition of PRL mRNA expression caused by treatment with the dopamine receptor agonist bromocriptine (2.5 mg/kg, b.i.d. x 5 days). Neither alpha-MT, haloperidol nor bromocriptine had a significant effect on pituitary VIP mRNA expression. Administration of the direct-acting 5-HT receptor agonist quipazine (5 mg/kg, b.i.d.) for 14 consecutive days caused a significant increase in pituitary PRL mRNA levels on day 1 and reached a plateau of 90% above control levels on days 7 and 14. VIP mRNA levels rose significantly on day 1 of quipazine treatment but thereafter fell to a minimum of 22% (1.0 kb) and 52% (1.7 kb) of control by day 14.(ABSTRACT TRUNCATED AT 250 WORDS)
Signs S A; Liu B; Wolford J; Carrillo A J
Molecular and cellular endocrinology
1994
1994-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0303-7207(94)90168-6" target="_blank" rel="noreferrer noopener">10.1016/0303-7207(94)90168-6</a>
Para-chlorophenylalanine treatment inhibits the expression of vasoactive intestinal peptide messenger RNA in rat anterior pituitary.
alpha-Methyltyrosine; Animals; Anterior/*drug effects/metabolism; Chemical; Depression; Dopamine/metabolism; Fenclonine/*pharmacology; Gene Expression Regulation/drug effects; Male; Messenger/*biosynthesis; Methyltyrosines/pharmacology; Pituitary Gland; Prolactin/metabolism; Rats; RNA; Serotonin/metabolism; Sprague-Dawley; Tryptophan Hydroxylase/antagonists & inhibitors; Vasoactive Intestinal Peptide/*biosynthesis/genetics
Adult male Sprague-Dawley rats were treated with para-chlorophenylalanine (pCPA) or alpha-methyl tyrosine (alpha-MT) to study the effect of serotonin or catecholamine depletion on the expression of vasoactive intestinal peptide (VIP) messenger RNA in the anterior pituitary. Single injections of pCPA (300 mg/kg) for two consecutive days resulted on the third day in a dramatic depletion of serotonin in the medial basal hypothalamus, and a significant reduction in the pituitary content of VIP mRNA (1.0 and 1.7 kb). The effect of pCPA on VIP mRNA appeared to be relatively specific for the anterior pituitary since VIP message levels in the cerebral cortex did not decrease. alpha-MT treatment, (150 mg/kg) for 2 consecutive days, reduced dopamine concentrations in the MBH but had no significant effect on pituitary VIP levels. In a time-course study, hypothalamic serotonin and pituitary VIP mRNA levels were significantly depressed 1-3 days after initiation of pCPA treatment; however, 12 days after pCPA treatment, serotonin concentrations in the hypothalamus approached control values and pituitary VIP mRNA content increased an average of 2-fold over control levels in an apparent rebound effect. pCPA-treated rats injected i.p. twice a day with
Signs S A; Dluzen D E; Carrillo A J
Brain research. Molecular brain research
1993
1993-01
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0169-328x(93)90070-6" target="_blank" rel="noreferrer noopener">10.1016/0169-328x(93)90070-6</a>