PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 2319107

Bromocriptine reduces rat thyrotropin beta-subunit mRNA stability.

A Levy·S L Lightman
View original source ↗Export metadata ↓

Abstract

We have examined the effect of orally administered bromocriptine on TSH beta-subunit messenger (m)RNA in the anterior pituitary glands of Sprague-Dawley rats using in situ and dot-blot hybridization histochemistry. Quantitative in situ hybridization of pituitary sections demonstrated a 60% reduction in TSH beta-subunit mRNA probe binding from rats fed a diet containing bromocriptine 10 mg/kg/day. This was confirmed by dot-blot analysis of nuclear and cytoplasmic pituitary extracts from the same tissue. Hybridization of cytoplasmic extracts of pituitary cells cultured under actinomycin D-induced transcription arrest showed that part of the effect of bromocriptine appeared to be mediated through a change in TSH beta-subunit mRNA stability and implies that the acute influence of dopamine on TSH metabolism may be transduced by control of TSH beta-subunit mRNA catabolism. This suggests a mechanism by which cells with relatively stable tissue specific mRNAs appear to respond rapidly to hormonal effects at the transcriptional level.

Explore related subjects

Administration, OralAnimalsBase SequenceBlotting, NorthernBromocriptineCells, CulturedDactinomycinDopamineGene Expression RegulationMaleMolecular Sequence DataNucleic Acid HybridizationOligonucleotide ProbesPituitary Gland, AnteriorRNA, MessengerRatsRats, Inbred StrainsThyrotropinTranscription, GeneticJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A Levy, S L Lightman. 1990. Bromocriptine reduces rat thyrotropin beta-subunit mRNA stability.. https://doi.org/10.1007/bf03348580

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Alginate microparticles as novel carrier for oral insulin delivery.

Alginate microparticles produced by emulsification/internal gelation were investigated as a promising carrier for insulin delivery. The procedure involves the dispersion of alginate solution containing insulin protein, into a water immiscible phase. Gelation is triggered in situ by instantaneous release of ionic calcium from carbonate complex via gentle pH adjustment. Particle size is controlled through the emulsification parameters, yielding insulin-loaded microparticles. Particle recovery was compared using several washing protocols. Recovery strategies are proposed and the influence on particle mean size, morphology, recovery yield (RY), encapsulation efficiency, insulin release profile, and structural integrity of released insulin were evaluated. Spherical micron-sized particles loaded with insulin were produced. The recovery process was optimized, improving yield, and ensuring removal of residual oil from the particle surface. The optimum recovery strategy consisted in successive washing with a mixture of acetone/hexane/isopropanol coupled with centrifugation. This strategy led to small spherical particles with an encapsulation efficiency of 80% and a RY around 70%. In vitro release studies showed that alginate itself was not able to suppress insulin release in acidic media; however, this strategy preserves the secondary structure of insulin. Particles had a mean size lower than the critical diameter necessary to be orally absorbed through the intestinal mucosa followed by their passage to systemic circulation and thus can be considered as a promising technology for insulin delivery.

Administration, Oral↗
PubMed2007

Treatment of recurrent pulmonary vein stenoses with endovascular stenting and adjuvant oral sirolimus.

The increasing use of radiofrequency catheter ablation for the cure of atrial fibrillation has led to iatrogenic pulmonary vein stenosis as a new clinical entity. The optimal diagnostic modality and treatment for pulmonary vein stenosis and restenosis remain unclear. We report the successful treatment of pulmonary vein restenosis following percutaneous balloon angioplasty, and for the first time, following surgical bovine pericardial patch angioplasty, with endovascular stenting and adjuvant oral sirolimus. Both patients remain asymptomatic at 1 year follow-up without evidence of restenosis.

Administration, Oral↗
PubMed2007

Induction of salivary polypeptides associated with parotid hypertrophy by gallotannins administered topically into the mouse mouth.

Isoproterenol-induced salivary polypeptides (IISP), a group of proline-rich proteins synthesized by mouse parotids, have been considered as markers for isoproterenol-induced parotid hypertrophy. Rodents fed diets containing high-tannin cereals (sorghum), also develop parotid hypertrophy. To test whether tannins are directly involved in provoking sialotrophic growth, we studied the effect of intraperitoneal and topical oral administrations of tannic acid (TA) on the induction of IISP polypeptides in endogamic mice (A/Snell). TA was characterized by HPLC chromatography and spectral analysis and shown to be composed solely of gallotannins, a complex family of glucose and gallic acid esters. IISP polypeptides were monitored in saliva by SDS-polyacrylamide gel electrophoresis during 36 h after ending TA stimulation. Single daily intraperitoneal administrations of TA for 3 consecutive days (0.033 mg/g bw/day), at variance of parallel administrations of isoproterenol (0.042 mg/g bw/day) failed to induce IISP polypeptides. However, repeated topical applications of TA into the mouse mouths (1.21 mg/g bw divided into three equal doses given at 4-h intervals within a single day) resulted in unequivocal induction of IISP polypeptides. That response was clearly intensified by increasing the stimulation frequency to eight equivalent doses given at 1.5-h intervals within a single day (corresponding to 3.23 mg/g bw) and even further by repeating this protocol for 3 days. Under these productive schemes of stimulations by TA, electrophoretic fractionation of parotid homogenates showed new polypeptide bands migrating in parallel to salivary IISP. These results suggest that topically administered gallotannins are effective inducers of trophic growth in mouse parotids.

Administration, Oral↗