Hypothalamic Thyrotropin-Releasing Hormone Regulates Pituitary Thyrotropin Beta- and Alpha-Subunit mRNA Levels in the Rat

1991 ◽  
Vol 53 (3) ◽  
pp. 276-280 ◽  
Author(s):  
Masami Murakami ◽  
Masatomo Mori ◽  
Yukio Kato ◽  
Isao Kobayashi
Keyword(s):  
Thyrotropin Releasing Hormone ◽  
Alpha Subunit ◽  
Mrna Levels ◽  
Releasing Hormone ◽  
Subunit Mrna

scholarly journals Mechanism of action of gonadotropin-releasing hormone upon gonadotropin α-subunit mRNA levels in the α T3-1 cell line: role of Ca2+ and protein kinase C

1995 ◽  
Vol 309 (1) ◽  
pp. 325-329 ◽  
Author(s):  
D Ben-Menahem ◽  
Z Shraga-Levine ◽  
P L Mellon ◽  
Z Naor
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Gonadotropin Releasing Hormone ◽  
Alpha Subunit ◽  
Similar Response ◽  
Mrna Levels ◽  
Α Subunit ◽  
Releasing Hormone ◽  
Subunit Mrna ◽  
Kinase C

Addition of [D-Trp6]gonadotropin-releasing hormone (GnRHa) to alpha T3-1 cells induced a very rapid response upon gonadotropin alpha-subunit mRNA which was detected after 30-60 min and was abolished by pretreatment with actinomycin D. A similar response was obtained with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA), or the Ca2+ ionophore, ionomycin. GnRHa (10 nM) also stimulated a secondary rise in alpha-subunit mRNA levels between 12 and 24 h of incubation. No additivity was obtained (at 60 min) upon the combined addition of GnRHa and PMA, GnRHa and ionomycin, or PMA and ionomycin. The effect of GnRHa upon alpha-subunit mRNA was blocked by the PKC inhibitors staurosporine or GF 109203X. Down-regulation of endogenous PKC activity resulted in inhibition of the stimulatory effect of gonadotropin-releasing hormone (GnRH), PMA and ionomycin. Removal of extra-cellular Ca2+ abolished the effect of GnRHa and PMA upon alpha-subunit mRNA levels. Interestingly PMA and ionomycin had no effect on alpha-subunit mRNA levels at 24 h of incubation; however, the combined addition of the drugs mimicked the late phase of GnRHa (10 nM) action. The data provide evidence that PKC and Ca2+ are involved in mediating the early and the late responses of GnRHa upon alpha-subunit mRNA elevation and that differential cross-talk exists between the messengers.

Effect of different types of stressors on peptide messenger ribonucleic acids in the hypothalamic paraventricular nucleus

1993 ◽  
Vol 128 (6) ◽  
pp. 485-492 ◽  
Author(s):  
Sandra Ceccatelli ◽  
Catello Orazzo
Keyword(s):  
Paraventricular Nucleus ◽  
Immobilization Stress ◽  
Thyrotropin Releasing Hormone ◽  
Hypothalamic Paraventricular Nucleus ◽  
Male Rats ◽  
Mrna Levels ◽  
Corticotropin Releasing Hormone ◽  
Ribonucleic Acids ◽  
Releasing Hormone ◽  
Different Types

Using in situ hybridization we have studied the effects of different types of stressors, such as ether, immobilization, cold and swimming, on the expression of several peptide messenger ribonucleic acids (mRNAs) in the hypothalamic paraventricular nucleus of adult male rats. Paraventricular nucleus sections were hybridized using synthetic oligonucleotide probes complementary to mRNA for corticotropin-releasing hormone, neurotensin, enkephalin and thyrotropin-releasing hormone. A clear upregulation of neurotensin mRNA was seen after ether and, to a lesser extent, after immobilization stress, whereas after the two other stressors neurotensin mRNA was undetectable, as in control rats. An increase in enkephalin mRNA was observed in a selective region of the dorsal part of the medioparvocellular subdivision of the paraventricular nucleus only after ether and immobilization stress. No significant changes were seen in corticotropin-releasing hormone and thyrotropin-releasing hormone mRNA levels in any of the experimental paradigms. The present results show selective changes for various peptide mRNAs in the paraventricular nucleus after various types of stress. Significant effects could be demonstrated only on neurotensin and enkephalin mRNA after ether and immobilization stress. This suggests that adaptive changes in the rate of synthesis, processing and transport of the peptide may develop over a longer period of time.

Effects of the gonadotrophin-releasing hormone agonist 'Zoladex' upon pituitary and gonadal function in hypogonadal (hpg) male mice: a comparison with normal male and testicular feminized (tfm) mice

1992 ◽  
Vol 8 (3) ◽  
pp. 249-258 ◽  
Author(s):  
I. S. Scott ◽  
M. K. Bennett ◽  
A. E. Porter-Goff ◽  
C. J. Harrison ◽  
B. S. Cox ◽  
...  
Keyword(s):  
Seminal Vesicle ◽  
Mrna Levels ◽  
Gonadal Function ◽  
Glycoprotein Hormone ◽  
Α Subunit ◽  
Releasing Hormone ◽  
Subunit Mrna ◽  
Serum Lh ◽  
Gonadotrophin Releasing Hormone ◽  
The Common

ABSTRACT Hypogonadal (hpg) mutant mice, with a congenital deficiency of hypothalamic gonadotrophin-releasing hormone (GnRH), and testicular feminized (tfm) mice, which lack a functional androgen receptor, were used to study the effects of the potent GnRH agonist 'Zoladex' (ICI 118630; d-Ser (But)6, Azgly10-GnRH) on pituitary and gonadal function. Zoladex (0.5 mg) in a sustained-release lactide—glycolide copolymer depot was administered subcutaneously under anaesthesia and was left in place for 7 days, after which time the effects of the drug upon pituitary and serum gonadotrophin concentrations, glycoprotein hormone subunit mRNAs and testicular morphology were investigated. At the pituitary level, Zoladex treatment resulted in a substantial reduction in LH content in normal males, and LH content was depressed in hpg mice even below the basal levels normally found in these mutants. Pituitary LH content in the Zoladex-treated animals was depressed in the tfm groups, but not to the same levels as those found in the normal and castrated normal mice. Zoladex treatment at the time of castration prevented the post-operative elevation in serum LH associated with castration alone. In the androgen-deficient tfm mouse, Zoladex did not depress the normally elevated serum LH levels. Serum LH in the hpg animals was, in all cases, below the limit of detection of the assay. Pituitary FSH content was depressed into the hpg range in both the normal and castrated animals, but there was no further depression in the hpg mice. The pituitary content was reduced in the tfm mice, again the effects not being as dramatic as in the normal and castrated animals. Serum FSH content, as measured by radioimmunoassay, was depressed by 50% in normal mice; there was no reduction in the hpg mice, however. With regard to pituitary gonadotrophic hormone gene expression, Zoladex administration to normal mice caused a dramatic reduction in LHβ mRNA content, to a level approximating that found in untreated hpg mice. The drug also depressed LHβ mRNA in the castrated group to the hpg range when given at the time of castration, whereas in untreated castrated mice there was a significant increase in LHβ mRNA. In the tfm mouse, which can be considered as a model for long-term failure of androgen feedback, Zoladex again induced a fall in LHβ mRNA, but not to the same extent as in the normal and normal castrated group. Zoladex had no effect on the already low levels of LHβ mRNA found in hpg mice. Pituitary FSHβ mRNA levels were not significantly altered by Zoladex in any of the treatment groups, whereas the drug induced a substantial rise in the common α-subunit mRNA in normal and hpg mice, to a level equalling that found in castrated tfm mice. In the latter two groups, Zoladex treatment did not result in a further increase in α-subunit mRNA above that found after castration alone, or in the untreated tfm mutant. Treatment for 7 days with Zoladex resulted in a significant increase in testis weight, with spermatogenesis advancing beyond the first meiotic division with many round spermatids found within the seminiferous tubules. However, the interstitial cells remained atrophic and there was evidence of seminal vesicle growth. Nevertheless, there was a small but significant increase in testicular androgen content. Administration of the agonist to hypophysectomized hpg mice did not stimulate testicular or seminal vesicle growth, suggesting that the drug does not stimulate steroidogenesis via a direct action upon the testis. Overall, the pharmacological effects of the drug appear to have turned off the transcription of the LHβ gene, with a consequent reduction in LH synthesis and probably also secretion in the longer term. With FSHβ, gene transcription was apparently unchanged and, with a substantial increase in the common α-subunit message, it would appear that the pituitary gland of Zoladex-treated animals may be predominantly biased towards FSH secretion. Although the circulating FSH levels as measured by radioimmunoassay were unaltered by Zoladex, there are several reports that GnRH agonists increase serum levels of bioactive hormones, perhaps by altering glycosylation of the FSH dimer glycoprotein.

Thyroid hormone coordinately regulates Na+-K+-ATPase alpha- and beta-subunit mRNA levels in kidney

1988 ◽  
Vol 254 (2) ◽  
pp. C323-C329 ◽  
Author(s):  
A. A. McDonough ◽  
T. A. Brown ◽  
B. Horowitz ◽  
R. Chiu ◽  
J. Schlotterbeck ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Atpase Activity ◽  
Time Course ◽  
Time Lag ◽  
Alpha Subunit ◽  
Beta Subunits ◽  
Mrna Levels ◽  
Dot Blot ◽  
Subunit Mrna ◽  
Enzyme Subunits

Synthesis of the sodium pump, Na+-K+-ATPase, is regulated by thyroid hormone in responsive tissues. The purpose of this study was to determine if triiodothyronine (T3) regulates the concentration of the mRNAs coding for the two enzyme subunits, alpha and beta, and the time course of the response. A single dose of T3 (250 micrograms/100 g body wt) was administered to hypothyroid rats that were killed at various times after injection. In the kidney cortexes of the T3-injected animals, as well as hypothyroid and euthyroid rats, alpha- and beta-mRNA concentrations were measured by dot blot using cDNAs corresponding to the two mRNAs; alpha-subunit abundance was measured by Western blot using antibodies to the enzyme, and Na+-K+-ATPase activity was measured enzymatically. alpha- and beta-mRNAs increased coordinately, after a 6-h time lag to 1.6-fold over hypothyroid levels by 12 h after T3. alpha-Subunit abundance increased significantly by 48 h and to 1.4-fold over hypothyroid by 72 h after T3. Na+-K+-ATPase activity increased with the same time course as the increase in alpha-subunit abundance to 1.3-fold over hypothyroid by 72 h after T3. We conclude that T3 regulates Na+-K+-ATPase synthesis and activity by coordinately increasing the mRNAs of both the alpha- and beta-subunits of the enzyme.

Pups removal enhances thyrotropin-releasing hormone mRNA in the hypothalamic paraventricular nucleus

1995 ◽  
Vol 133 (3) ◽  
pp. 354-360 ◽  
Author(s):  
Rosa Maria Uribe ◽  
Patricia Joseph-Bravo ◽  
Jean-Louis Charli
Keyword(s):  
Estrous Cycle ◽  
Paraventricular Nucleus ◽  
Northern Blot Analysis ◽  
Preoptic Area ◽  
Thyrotropin Releasing Hormone ◽  
Hypothalamic Paraventricular Nucleus ◽  
Negative Regulator ◽  
Neuron Activity ◽  
Mrna Levels ◽  
Releasing Hormone

Uribe RM, Joseph-Bravo P, Charli J-L. Pups removal enhances thyrotropin-releasing hormone mRNA in the hypothalamic paraventricular nucleus. Eur J Endocrinol 1–60. ISSN 0804–4643 Previous studies have shown that lactation and suckling alter thyrotropin-releasing hormone (TRH) biosynthesis in hypothalamic paraventricular neurons. The amounts of paraventricular TRH mRNA and mediobasal hypothalamus (MBH) TRH were determined following removal of the pups to examine whether paraventricular TRH neuron activity is altered during the transition from lactation to estrous cycle. Paraventricular TRH mRNA and MBH TRH levels were determined by Northern blot analysis and radioimmunoassay, respectively. We had shown previously that after an 8-h withdrawal of the pups at mid-lactation the MBH TRH and paraventricular TRH mRNA levels are not modified. This condition was compared to one where pups were removed for 56 h, finding a significant decrease (46%, p < 0.005) of MBH TRH and a significant increase (156%, p < 0.02) of paraventricular TRH mRNA. The effect observed in the paraventricular TRH mRNA was correlated negatively with the serum corticosterone levels, a potential negative regulator of paraventricular TRH mRNA. The results were similar if a 1-h suckling period was introduced 8 h after withdrawal of the pups to induce a transient increase of corticosterone levels. The pattern of TRH mRNA was specific to the paraventricular nucleus because there was no enhancement in the preoptic area-anterior hypothalamus. In summary, our data suggest that TRH biosynthesis in paraventricular neurons is slowly adjusted after withdrawal of the pups, possibly to prepare TRH neurons to the new secretory demands of the estrous cycle. JL Charli, Instituto de Biotecnologia, UNAM, AP 510-3, Cuernavaca, Mor. 62271, México

Regulation of growth hormone expression by thyrotropin-releasing hormone through the pituitary-specific transcription factor Pit-1 in chicken pituitary

2004 ◽  
Vol 52 (4) ◽  
pp. 389-402 ◽  
Author(s):  
P. Van As ◽  
C. Careghi ◽  
V. Bruggeman ◽  
O. M. Onagbesan ◽  
S. Van der Geyten ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mrna Expression ◽  
Developmental Stages ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Thyrotropin Releasing Hormone ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Releasing Hormone ◽  
Pou Domain

Pit-1 is a pituitary-specific POU-domain DNA binding factor, which binds to and trans-activates promoters of growth hormone- (GH), prolactin- (PRL) and thyroid stimulating hormone beta- (TSHβ) encoding genes. Pit-1 has been identified in several mammalian and avian species. Thyrotropin-releasing hormone (TRH) is located in the hypothalamus and it stimulates TSH, GH and PRL release from the pituitary gland. In the present study, we successfully developed a competitive RT-PCR for the detection of Pit-1 expression in the chicken pituitary, that was sensitive enough to detect picogram levels of Pit-1 mRNA. Applying this method, the effect of TRH injections on Pit-1 mRNA expression was determined in the pituitary of chick embryos and growing chicks. In both 18-day-old embryos and 10-day-old male chicks the Pit-1 mRNA expression was significantly increased following TRH injection, thereby indicating that the stimulatory effects of TRH on several pituitary hormones is mediated via its effect on Pit-1 expression. Therefore, a semi-quantitative RT-PCR method was used to detect possible changes in GH levels. TRH affected the GH mRNA levels at both developmental stages. These results, combined with the data on Pit-1 mRNA expression, indicate that Pit-1 has a role in mediating the stimulatory effects of TRH on pituitary hormones like GH.

scholarly journals Acetylcholine receptor alpha-subunit mRNA is increased by ascorbic acid in cloned L5 muscle cells: Northern blot analysis and in situ hybridization.

1989 ◽  
Vol 108 (5) ◽  
pp. 1823-1832 ◽  
Author(s):  
O Horovitz ◽  
D Knaack ◽  
T R Podleski ◽  
M M Salpeter
Keyword(s):  
Ascorbic Acid ◽  
In Situ Hybridization ◽  
Northern Blot ◽  
Blot Analysis ◽  
Northern Blot Analysis ◽  
Alpha Subunit ◽  
Mrna Levels ◽  
Surface Receptors ◽  
Subunit Mrna

Ascorbic acid is the major factor in brain extract responsible for increasing the average acetylcholine receptor (AChR) site density on the cloned muscle cell line L5. In the present study, we show that this effect of ascorbic acid requires mRNA synthesis, and that the mRNA level for the AChR alpha-subunit is increased to about the same level as are the surface receptors. We have found no increase in the mRNA levels of the beta-, gamma-, and delta-subunits, or in the mRNAs of other muscle-specific proteins, such as that of light chain myosin 2, alpha-actin, and creatine kinase. By in situ hybridization, we further show that the increase in alpha-mRNA in response to ascorbic acid is exclusively in myotubes and is located near clusters of nuclei. mRNA levels for the alpha-subunit in mononucleated cells are very low and do not significantly increase in response to ascorbic acid. The mononucleated cells are thus excluded as a possible source for the increase in alpha-subunit mRNA detected by Northern blot analysis. Our results indicate that there is a very specific action of ascorbic acid on the regulation of AChR alpha-mRNA in the L5 muscle cells, and that the expression of surface receptors in these cells is limited by the amount of AChR alpha-subunit mRNA.

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