An Early Pineal-Induced Suppression of Pituitary Prolactin mRNA Levels in Light-Deprived Male Hamsters

1989 ◽  
Vol 50 (5) ◽  
pp. 506-512 ◽  
Author(s):  
John S. Massa ◽  
David E. Blask
Keyword(s):  
Mrna Levels ◽  
Pituitary Prolactin ◽  
Prolactin Mrna

Regulation of LH subunit mRNA levels by gonadal hormones in female rats

1988 ◽  
Vol 1 (1) ◽  
pp. 49-60 ◽  
Author(s):  
S. D. Abbot ◽  
K. Docherty ◽  
R. N. Clayton
Keyword(s):  
Gene Expression ◽  
Physiological Role ◽  
Gonadal Hormones ◽  
Ovariectomized Rats ◽  
Mrna Levels ◽  
Subunit Gene ◽  
Progesterone Treatment ◽  
Serum Lh ◽  
Pituitary Prolactin ◽  
Prolactin Mrna

ABSTRACT To determine the physiological role of the ovaries in regulation of LH subunit gene expression, levels of cytoplasmic mRNA were measured in a cDNA-RNA dot-blot hybridization assay. An increase (twofold) in α mRNA was first detected 8 days after ovariectomy and then remained stable for 4 weeks. In contrast, LH-β mRNA increased by 60–79% within 12 h of removing the ovaries and then rose progressively to six times the intact values at 3 and 4 weeks. Increases in LH-β mRNA were always greater than those of α mRNA. Oestradiol, and oestradiol plus progesterone, but not progesterone alone, prevented the rise in α and LH-β mRNA 10 days after ovariectomy. Three days after ovariectomy, α mRNA, but not LH-β mRNA, was suppressed to below intact control values by oestradiol and oestradiol plus progesterone, indicating greater sensitivity of α mRNA to oestradiol inhibition at this stage. A single injection of oestradiol (1 μg s.c.) to rats ovariectomized 14 days previously transiently suppressed α and LH-β mRNA levels and serum LH concentrations in parallel for 1–8 h, after which high preinjection values were restored. However, pituitary LH content remained suppressed after LH mRNA levels had returned to the control values of ovariectomized rats. In most instances there was a qualitative positive correlation between changes in α and LH-β mRNA, pituitary LH content and serum LH concentrations. LH content reflected LH-β mRNA changes more closely than those of α mRNA. However, in oestradiol-treated rats ovariectomized 10 days previously, LH content remained increased despite normalization of the LH-β and α mRNA levels, suggesting differential sensitivity to oestradiol of the gene expression and translational processes. Thus divergence of pre- and post-translational regulation of LH biosynthesis was demonstrated. These results imply an important physiological role for female sex hormones in the control of LH gene expression and LH biosynthesis. Prolactin mRNA fell by 30–50% for the first 2 weeks after ovariectomy, but by 3 and 4 weeks values were similar to those of intact controls. Serum and pituitary prolactin levels were reduced by 50% or more at all time-points, despite normalization of mRNA. Treatment of ovariectomized rats for 10 days with oestradiol and progesterone, either alone or combined, reversed the fall in prolactin mRNA and serum and pituitary prolactin levels. These changes in prolactin gene expression and synthesis were opposite to those of LH subunits in response to the same in-vivo hormone manipulations. Growth hormone mRNA levels were unchanged by ovariectomy, oestradiol or progesterone treatment. Levels of TSH-β mRNA increased slightly (maximum up to 50%) after ovariectomy, but were unaltered by oestradiol and progesterone treatment for 10 days. These results support the view that α mRNA changes, resulting from ovariectomy, oestradiol and progesterone treatment, occur in gonadotrophs and not thyrotrophs, which also express the α subunit gene.

Regulation of LH subunit and prolactin mRNA by gonadal hormones in mice

1989 ◽  
Vol 2 (3) ◽  
pp. 213-224 ◽  
Author(s):  
G. Saade ◽  
D. R. London ◽  
M. R. A. Lalloz ◽  
R. N. Clayton
Keyword(s):  
Gonadal Hormones ◽  
Female Rats ◽  
Pituitary Hormone ◽  
Mrna Levels ◽  
Α Subunit ◽  
Subunit Mrna ◽  
Serum Lh ◽  
Prolactin Content ◽  
Pituitary Prolactin ◽  
Prolactin Mrna

ABSTRACT The effect of castration and gonadal steroid replacement on the concentrations of LH-β and α subunit and prolactin mRNA was examined in mice. Mouse LH-β, α and prolactin mRNAs were approximately 0·8, 0·7 and 1·1 kb in size respectively. After ovariectomy, LH-β mRNA levels increased 2- to 2·5-fold, while α mRNA levels increased 2·5-fold 6 and 10 days after ovariectomy. Serum LH rose after 2 days to reach six times control values at 10 days. Pituitary LH content doubled by 8 days after ovariectomy. Prolactin mRNA levels decreased to 50–60% of control at 3, 6, 8 and 10 days after ovariectomy and parallelled the fall in serum prolaction. Pituitary prolactin content fell more slowly, to 50% of intact control values by 10 days. The increase in both LH-β and α subunit mRNA, and decrease in prolactin mRNA, and serum and pituitary hormone changes, after ovariectomy were prevented by oestradiol or oestradiol plus progesterone replacement. Levels of LH-β mRNA increased more quickly in male than in female mice, theearliest change being seen 24 h after orchidectomy. Maximum values (two- to threefold) were found on day 6 after orchidectomy. Concentrations of α mRNA increased by 12 h to between 2 and 2·5 times control from 3 to 10 days after orchidectomy. Serum LH doubled by 12 h and was three to five times greater than control values up to 10 days. Pituitary LH content fell by 48 h before gradually increasing to intact values after 10 days. Prolactin mRNA levels decreased progressively from 2 days after orchidectomy, and this decrease was preceded by a fall in serum and pituitary prolactin which remained low throughout the experiment. Testosterone treatment attenuated the rise in α mRNA, prevented the rise in LH-β mRNA and serum LH and partially restored the decrease in prolactin mRNA seen after orchidectomy. We conclude that in mice, as in rats and ewes, both LH-β and α subunit mRNAs are negatively regulated by gonadal steroids, whereas prolactin mRNA is positively regulated, although there are temporal differences in patterns of mRNA responses between males and females. By comparison with female rats the rise in LH-β mRNA after ovariectomy was slower in mice. Moreover, the discordant changes in pituitary LH content and LH subunit mRNAs seen in mice after castration were not observed in rats. Furthermore, pituitary prolactin and prolactin mRNA do not fall after orchidectomy of rats. The modest (50%) increase of LH-β mRNA after castration of mice suggests that an increase in mRNA is not necessarily required for increased LH production.

Cloning of a toad prolactin cDNA: expression of prolactin mRNA in larval and adult pituitaries

1993 ◽  
Vol 11 (3) ◽  
pp. 343-349 ◽  
Author(s):  
N Takahashi ◽  
K Yamamoto ◽  
S Kikuyama
Keyword(s):  
Amino Acid ◽  
Sea Turtle ◽  
Sequencing Analysis ◽  
Mrna Levels ◽  
Amino Acid Residues ◽  
Polymerase Chain ◽  
Prolactin Synthesis ◽  
Pituitary Prolactin ◽  
Prolactin Mrna ◽  
Reaction Sequencing

ABSTRACT A toad (Bufo japonicus) prolactin cDNA was specifically amplified from cDNAs constructed from the total RNA of adenohypophyses, employing the DNA polymerase chain reaction. Sequencing analysis revealed that the cDNA clone thus obtained was 602 bp in length, and encoded the C-terminal 134 amino acid residues of the toad prolactin molecule. The length of the toad prolactin mRNA was estimated to be about 1·0 kb by Northern blot analysis. The partial amino acid sequence deduced from the nucleotide sequence showed the following homologies between toad prolactin and the prolactins of other vertebrates: 69% with man, 80% with chicken, 81% with sea turtle, 91% with bullfrog and 38% with salmon. Using the cDNA as a probe, developmental and seasonal changes in prolactin mRNA levels in the pituitaries of toads were studied. Prolactin mRNA in the pituitary rose as metamorphosis progressed and declined at the end of metamorphosis. During the breeding season the pituitary content of prolactin mRNA was relatively high. This finding suggests that the increases in plasma and pituitary prolactin levels in larvae at metamorphic climax and in adults that remain in or migrate into water, as reported previously, accompany the increase in prolactin synthesis.

scholarly journals The influence of sGnRH-A and antidopaminergic drug – pimozide – on prolactin mRNA synthesis in female Prussian carp (Carassius gibelio Bloch) in vivo

2013 ◽  
Vol 58 (No. 1) ◽  
pp. 31-36
Author(s):  
J. Chyb ◽  
M. Socha ◽  
P. Szczerbik ◽  
M. Sokolowska-Mikolajczyk ◽  
T. Mikołajczyk ◽  
...  
Keyword(s):  
Gonadotropin Releasing Hormone ◽  
Inhibitory Influence ◽  
Mrna Levels ◽  
Mrna Synthesis ◽  
Releasing Hormone ◽  
Prussian Carp ◽  
Carassius Gibelio ◽  
Prolactin Synthesis ◽  
Prolactin Mrna

Effects of salmon gonadotropin releasing hormone analogue (sGnRH-A) and antidopaminergic drug, pimozide, on the synthesis of prolactin mRNA in vivo in female Prussian carp (Carassius gibelio Bloch) during two different stages of the reproductive cycle were evaluated. The results showed that the lowest dose of sGnRH-A (5 μg/kg body weight) significantly stimulated the mRNA synthesis in fish during the recrudescence as well as during the preovulatory period, higher doses of this compound having no significant effect on prolactin mRNA synthesis. The blocker of dopamine receptors, pimozide, also potentiated prolactin mRNA synthesis – in recrudescent females it increased mRNA levels at the dose of 1 mg/kg, while in the preovulatory period all of the used pimozide doses (1, 5, and 10 mg/kg) were responsible for the increase of prolactin mRNA levels. Taken together, the above results suggest that gonadotropin releasing hormone (GnRH) is the factor responsible for the stimulation of prolactin synthesis, while dopamine has an inhibitory influence on the prolactin production.  

Tri-iodothyronine and phenytoin reduce prolactin messenger RNA levels in cultured rat pituitary cells

1986 ◽  
Vol 109 (3) ◽  
pp. 359-364 ◽  
Author(s):  
J. R. E. Davis ◽  
T. C. Lynam ◽  
J. A. Franklyn ◽  
K. Docherty ◽  
M. C. Sheppard
Keyword(s):  
Gene Transcription ◽  
Messenger Rna ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Prolactin Release ◽  
Dot Hybridization ◽  
Prolactin Gene ◽  
Rat Pituitary ◽  
Rat Pituitary Cells ◽  
Prolactin Mrna

ABSTRACT Thyroid hormones may regulate prolactin gene transcription. We have previously found that phenytoin inhibits tri-iodothyronine (T3) nuclear binding, and have suggested that phenytoin may act as a partial T3 agonist. We have therefore investigated the effects of phenytoin and T3 on prolactin release and gene transcription, using the technique of cytoplasmic dot hybridization with complementary DNA probes to estimate prolactin messenger (m) RNA concentrations in cytoplasm from cultured rat pituitary cells. Tri-iodothyronine treatment led to a small but significant fall in prolactin release by 72 h, but caused marked dose- and time-dependent reductions in prolactin mRNA levels at 48–72 h. Phenytoin, however, caused more rapid falls in both prolactin release and mRNA concentrations. Neither T3 nor phenytoin significantly altered GH mRNA levels. These studies suggest effects of phenytoin similar, but not identical, to those of T3 in the lactotroph. J. Endocr. (1986) 109, 359–364

scholarly journals Prolactin delays hair regrowth in mice

2006 ◽  
Vol 191 (2) ◽  
pp. 415-425 ◽  
Author(s):  
A J Craven ◽  
A J Nixon ◽  
M G Ashby ◽  
C J Ormandy ◽  
K Blazek ◽  
...  
Keyword(s):  
Hair Growth ◽  
Prolactin Receptor ◽  
Growth Cycle ◽  
Hair Cycle ◽  
Normal Hair ◽  
Endocrine Factors ◽  
Pituitary Prolactin ◽  
The Relationship ◽  
Deficient Mice ◽  
Prolactin Mrna

Mammalian hair growth is cyclic, with hair-producing follicles alternating between active (anagen) and quiescent (telogen) phases. The timing of hair cycles is advanced in prolactin receptor (PRLR) knockout mice, suggesting that prolactin has a role in regulating follicle cycling. In this study, the relationship between profiles of circulating prolactin and the first post-natal hair growth cycle was examined in female Balb/c mice. Prolactin was found to increase at 3 weeks of age, prior to the onset of anagen 1 week later. Expression of PRLR mRNA in skin increased fourfold during early anagen. This was followed by upregulation of prolactin mRNA, also expressed in the skin. Pharmacological suppression of pituitary prolactin advanced dorsal hair growth by 3.5 days. Normal hair cycling was restored by replacement with exogenous prolactin for 3 days. Increasing the duration of prolactin treatment further retarded entry into anagen. However, prolactin treatments, which began after follicles had entered anagen at 26 days of age, did not alter the subsequent progression of the hair cycle. Skin from PRLR-deficient mice grafted onto endocrine-normal hosts underwent more rapid hair cycling than comparable wild-type grafts, with reduced duration of the telogen phase. These experiments demonstrate that prolactin regulates the timing of hair growth cycles in mice via a direct effect on the skin, rather than solely via the modulation of other endocrine factors.

Molecular cloning and nucleotide sequence analysis of complementary DNA for bullfrog prolactin

1990 ◽  
Vol 5 (3) ◽  
pp. 281-287 ◽  
Author(s):  
N. Takahashi ◽  
K. Yoshihama ◽  
S. Kikuyama ◽  
K. Yamamoto ◽  
K. Wakabayashi ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rana Catesbeiana ◽  
Amino Acid Sequences ◽  
Protein Sequencing ◽  
Nucleotide Sequence Analysis ◽  
Cdna Expression Library ◽  
Mrna Levels ◽  
Expression Library ◽  
Untranslated Sequence ◽  
Prolactin Mrna

ABSTRACT A prolactin cDNA was cloned from a cDNA expression library constructed from total RNA of bullfrog (Rana catesbeiana) adenohypophyses by immunoscreening with antiserum against bullfrog prolactin. The cDNA clone thus obtained contained a 249 bp insert. Using this clone as a probe, plaque hybridizations were performed and two additional clones obtained. These clones had a polyadenylation site different from that of the first obtained clone, suggesting that the 3′-untranslated sequence was heterogeneous in length. The longest clone contained 830 bp, which encoded part of the signal peptide and the entire sequence of mature prolactin. The deduced amino acid sequence was in good accord with that determined by direct protein sequencing of purified bullfrog prolactin. The length of the bullfrog prolactin mRNA was estimated by Northern blot analysis to be about 1·0 kb. Homologies of prolactin nucleotide and amino acid sequences between bullfrog and other vertebrates were 64 and 65% for man, 66 and 68% for pig, 61 and 52% for rat, 69 and 74% for chicken, and 50 and 35% for salmon respectively. Highly conserved regions reported for mammalian prolactins also existed in bullfrog prolactin. Homologies of nucleotide and amino acid sequences between prolactin and GH of bullfrog origin were 49 and 25% respectively. Using the cDNA, the content of prolactin mRNA in the pituitary glands of metamorphosing tadpoles was measured. Prolactin mRNA levels rose at the mid-climax stage, suggesting that the increase in plasma and pituitary prolactin levels known to occur at the climax stage accompanies the increase in prolactin synthesis.

scholarly journals Transcriptional and posttranscriptional regulation of the rat prolactin gene by calcium.

1990 ◽  
Vol 10 (2) ◽  
pp. 442-448 ◽  
Author(s):  
G M Preston ◽  
W M Billis ◽  
B A White
Keyword(s):  
Posttranscriptional Regulation ◽  
In Vitro Transcription ◽  
Gh3 Cells ◽  
Mrna Levels ◽  
Nuclear Extracts ◽  
Nuclear Site ◽  
Gene Treatment ◽  
Prolactin Gene ◽  
Prolactin Mrna

The rat prolactin gene is expressed at a high basal level in the pituitary tumor GH3 cell line. Culturing GH3 cells in a low-Ca2+, serum-free medium (SFM) depresses prolactin mRNA levels, and subsequent addition of Ca2+ to the SFM results in a specific, gradual, and sustained increase in prolactin mRNA levels. We have now examined whether the observed increase in prolactin mRNA levels can be attributed solely to an increase in the transcriptional rate of the prolactin gene. Treatment of GH3 cells in SFM with 0.4 mM CaCl2 for 24 to 48 h increased cytoplasmic prolactin mRNA levels by 5- to 10-fold, whereas the transcriptional rate of the prolactin gene was increased by less than twofold over values for SFM controls. Prolactin mRNA levels increased progressively during the 24-h period after Ca2+ addition, whereas prolactin gene transcription never exceeded a twofold increase over values for SFM controls. The activities of nuclear extracts from control and Ca2(+)-induced cells were examined in an in vitro transcription assay. The two extracts directed transcription from the prolactin promoter and the adenovirus major late promoter equally well. Cycloheximide had no effect on the ability of Ca2+ to increase or maintain prolactin mRNA levels. In dactinomycin mRNA clearance experiments, prolactin mRNA was cleared at the same rate in the absence and presence of Ca2+. These results demonstrate that although Ca2+ has a small effect on the transcriptional rate of the prolactin gene, Ca2+ produces a significant increase in prolactin mRNA levels by acting at a posttranscriptional site(s). Furthermore, Ca(2+) appears to increase prolactin mRNA levels by posttranslational modification of a stable protein, probably at a nuclear site.

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