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At least 631 records · Page 35Linked to original sources
PubMed1981

Effect of loperamide, a peripheral opiate agonist, on circulating glucose, free fatty acids, insulin, C-peptide and pituitary hormones in healthy man.

The effect of acute oral administration of loperamide (4, 8 and 16 mg), a peripheral opiate agonist used in the treatment of diarrhoea, on several metabolic and endocrine variables has been evaluated in healthy volunteers in comparison with placebo. Plasma glucose was significantly raised by all three doses, whereas serum IRI and C-peptide were decreased and serum FFA was significantly increased only after loperamide 8 and 16 mg; serum PRL, GH, LH and FSH did not change. The data suggest that opiates may be involved in the regulation of glycaemia, probably by modifying islet hormone secretion by acting at a peripheral site, since loperamide does not cross the blood-brain barrier. Although the precise mechanism of these actions is unknown, it is suggested that the effects of loperamide are mediated either by stimulation of opiate receptors per se, or by suppression of acetylcholine release from cholinergic nerve endings. The lack of change in pituitary hormone secretion by loperamide is in agreement with previous observations indicating that opiate effects on PRL, GH and gonadotropins occur at the level of the central nervous system.

Adult↗
PubMed1999

Isolation of human lutropin from woman urine and comparison of its properties with pituitary hormone.

Lutropin was isolated from woman preovulatory urine by immunoaffinity chromatography using a column with monoclonal antibody (mAb) anti-beta hLH(37) coupled to Sepharose CL 4B. As it was demonstrated the isolated hormone, as well as pituitary lutropin, were separated in SDS-PAGE into several well visible fractions with 30-94 kDa molecular mass and scarcely visible fractions with 14-20 kDa. All fractions reacted only with mAb anti-alpha hCG(99)-HRP but not with mAb anti-beta hLH-HRP. Pretreatment of pituitary lutropin with PN-Gase F did not affect its electrophoretic pattern. After boiling the hormone with SDS and beta ME no fractions in SDS-PAGE were observed. No substantial differences in affinity chromatography on Con A-Sepharose between pituitary and urinary lutropin were noted. Some differences between these two hormone preparations were observed in assays performed with several ELISA variants. Using two pairs of mAbs anti-beta hLH for ELISA technique no hormone was assayed in urine samples from women, collected between 12 and 16 days of menstrual cycles.

Blotting, Western↗
PubMed1976

Pituitary hormone levels in plasma of the human fetus after administration of LRH.

The concentrations of hFSH, hLH/hCG, hGH, and hTSH1 were measured in maternal and fetal blood during the second trimester of pregnancy before and after the administration of 10 mug LRH to 9 fetuses. A comparison was performed with 9 control fetuses not receiving LRH. The initial value of hFSH was significantly higher in female than in male fetuses (P less than 0.01) and in both sexes exceeded the low maternal hFSH level. A similar fetomaternal difference existed also for plasma hGH, in contrast to plasma hLH/hCG, which concentration was higher in maternal than in fetal blood LRH did not cause any change of circulating hFSH, hLH/hCG, and hTSH levels in the fetus 10 min after its administration. A rise of fetal hGH levels occurred during the observation time irrespective of LRH administration. In amniotic fluid, the hFSH concentration accorded with that in fetal blood, and the hLH/hCG concentration with that in maternal blood. The fetal plasma levels of these pituitary hormones suggest selective release mechanisms for the various peptides. The causes of the absent response of blood gonadotropin levels to LRH in the fetus are discussed.

Chorionic Gonadotropin↗
PubMed1997

Evaluation of circulating galanin levels after exercise-induced pituitary hormone secretion in man.

The neuropeptide galanin (GAL) is widely distributed in the central and peripheral nervous systems, anterior pituitary, and adrenal medulla. GAL is colocalized with corticotropin (ACTH) in the human pituitary and with epinephrine (E) and norepinephrine (NE) in chromaffin cells of the adrenal medulla. The function of GAL in peripheral tissues is not known, although the presence of the peptide in corticotrophs and the adrenal gland suggest that it participates in stress responses. In the present study, we investigated whether GAL is cosecreted with ACTH during activation of corticotrophs by an acute physical exercise test. Circulating levels of GAL and pituitary hormones were measured in healthy exercise-tested and control male subjects. Blood samples were collected during basal conditions, maximal power output (MPO), and the recovery period. Control subjects were sampled during the resting condition. The pituitary response to exercise was characterized by a significant increase in ACTH plasma levels (peak value 13.28 +/- 2.19 v 6.68 +/- 1.01 pmol/L, P < .05) and growth hormone (GH) serum levels (peak value, 14.53 +/- 5.59 v 0.29 +/- 0.1 microg/L, P < .02), with the peak in hormone levels detected 15 minutes after the end of exercise. No change in circulating prolactin (PRL) levels was detected. An expected significant increase in plasma levels of both E (peak value, 1,574.41 +/- 403.31 v 267.44 +/- 60.03 pmol/L, P < .01) and NE (peak value, 7,275.25 +/- 955.80 v 961.51 +/- 168.40 pmol/L, P < .01) was also observed. Plasma GAL levels were not affected by the acute exercise test, with the levels being comparable to baseline during the exercise test and the recovery phase. At any sample time, GAL values were comparable between exercise-tested and control subjects. These data show that despite the colocalization of GAL and ACTH within the same pituitary cells, the two peptides are not coreleased in response to stress resulting from acute physical exercise. Furthermore, pituitary GAL seems not to be involved in the stimulation of GH secretion in exercise-tested subjects. The results also indicate that GAL is not coreleased with E or NE in response to the exercise-induced stress condition.

Adrenocorticotropic Hormone↗
PubMed1986

Concentrations of ovarian and pituitary hormones following prostaglandin F2 alpha-induced luteal regression in ewes varies with day of the estrous cycle at treatment.

Prostaglandin F2 alpha (PGF2 alpha) was injected on d 5, 8 or 11 postestrus in ewes to determine how stage of the estrous cycle would affect PGF2 alpha-induced changes in concentrations of ovarian and pituitary hormones and intervals to the onset of estrus and the preovulatory surge of luteinizing hormone (LH). Initial concentrations of progesterone and average values during the 12 h after PGF2 alpha were related positively to the day of cycle on which PGF2 alpha was administered. Patterns of decline in progesterone after injection of PGF2 alpha were similar among the 3 d. Concentrations of LH in plasma increased in a similar manner from 0 to 12 h in all ewes. After 12 h LH continued to increase, plateaued or declined in ewes treated on d 5, 8 or 11, respectively. Initial concentrations of follicle stimulating hormone (FSH) in plasma were related positively to day of treatment. After treatment with PGF2 alpha, FSH increased within 2 h on d 5 but declined by that time on d 8 or 11. Concentrations of estradiol following treatment did not vary with day. The onset of estrus and the preovulatory surge of LH occurred at 36 and 35, 40 and 45, and 48 and greater than 48 h in ewes treated on d 5, 8 or 11, respectively. It is concluded that: 1) the initial increase in LH is dependent on a decrease in plasma progesterone and 2) differences in patterns of secretion of gonadotropins before the preovulatory surge of LH might be caused by differences in progesterone or progesterone:-estradiol ratio when luteal regression is induced on different days of the estrous cycle.

Animals↗
PubMed1988

Effects of hypophysectomy and pituitary hormones on hepatic microsomal carboxylesterase isozymes in male rats.

Hepatic microsomal carboxylesterase (EC 3.1.1.1) from rat liver microsomes showed a different capacity for the hydrolysis of various substrates. In hypophysectomized male rats, hepatic carboxylesterase activities showed substrate-dependent changes, i.e., an decrease in malathion and p-nitrophenylacetate hydrolases and increase in isocarboxazid hydrolase. When human growth hormone is administered to hypophysectomized male rats, carboxylesterase activities were decreased. Conversely, subcutaneous injection of ovine prolactin to hypophysectomized rats, carboxylesterase activities showed substrate-dependent changes. On the other hand, in hypophysectomized male rats, the amount of carboxylesterase isozymes showed different changes, i.e., an increase in the amount of RL2 contents and decrease in RL1 contents, and the amount of RH1 was not changed. These results suggested that hepatic microsomal carboxylesterases are regulated, at least in part, by some pituitary hormones, and that these hormones have selective effects on the different isozymes of carboxylesterase.

Animals↗
PubMed2001

Combined pituitary hormone deficiency caused by compound heterozygosity for two novel mutations in the POU domain of the Pit1/POU1F1 gene.

The POU homeodomain containing transcriptional activator POU1F1, formerly called Pit1 or GHF-1, is required for the embryological determination and postnatal secretory function of the GH-, PRL-, and TSH-producing cells in the anterior pituitary. Several mutations in the gene encoding POU1F1 have been described, resulting in a syndrome of combined pituitary hormone deficiency involving these three hormones. Most of the patients with this phenotype have either a dominant negative mutation in codon 271 (R271W) or are homozygous for a recessive mutation in the POU1F1 gene; to date only one case has been reported with compound heterozygosity for two point mutations. Here, we describe a boy with severe deficiencies of GH, PRL, and TSH who had compound heterozygosity for two novel point mutations in the POU1F1 gene: a 1-bp deletion frameshift mutation (747delA), the first one described to date in this gene, which leads to a nonfunctional truncated protein lacking the entire DNA recognition helix of the POU homeodomain, and a missense mutation in the C-terminal end of the fourth alpha-helix of the POU-specific domain (W193R),which causes a 500-fold reduction in the ability to bind to DNA and activate transcription.

Cell Line↗
PubMed1994

Circadian rhythm of tryptophan, serotonin, melatonin, and pituitary hormones in schizophrenia.

Circadian rhythm abnormalities have been described mostly with respect to manic-depressive illness; little information is available concerning circadian rhythms and schizophrenia or their influence on neuroleptic drugs. We showed previously that the MESOR of dopamine is higher in schizophrenic patients than in healthy subjects and that women who are drug-free schizophrenic have lower prolactin MESORs and lower amplitudes than healthy women. We now report the data of a cosinor analysis of tryptophan, serotonin, melatonin, and pituitary hormones in the blood of 34 healthy subjects, 90 drug-free schizophrenics, and 25 neuroleptic-treated schizophrenic patients. This data indicated a significant phase advance of serum tryptophan, prolactin, and melatonin concentrations, a trend toward a phase advance in serotonin. Thyroid stimulating hormone (TSH), and growth hormone concentrations, and decreases in the TSH MESORs among patients compared to healthy subjects. These results suggest that circadian changes, such as phase advances and alterations in MESOR, are not only present in depression but also in schizophrenia. Although neuroleptic treatment raised the prolactin MESOR and amplitude, it did not elicit any change in circadian rhythmicity among the other parameters.

Adolescent↗
PubMed1999

Reverse transcription polymerase chain reaction analysis of pituitary hormone, Pit-1 and steroidogenic factor-1 messenger RNA expression in pituitary tumors.

Pit-1 is a transcription factor that appears early in embryonic pituitary gland formation and is necessary for the development of somatotropes, lactotropes and thyrotropes. Steroidogenic factor-1 (SF-1) is another early appearing transcription factor that is involved in the development of gonadotropes. In this study we have compared RT-PCR analysis of hormone mRNA with traditional IHC for classification of 27 pituitary tumors and have evaluated the correlation of Pit-1 and SF-1 mRNA with hormone mRNA. RT-PCR detected concordant hormone mRNA in 100% of GH IHC positive, 100% of PRL IHC positive, 33% of TSH IHC positive, and 93% of gonadotropin IHC positive tumors. IHC, however, was concordant in only 71% of GH mRNA positive, 78% of PRL mRNA positive, 17% of TSH beta mRNA positive, and 76% of FSH beta mRNA positive tumors. Pit-1 mRNA was positive in 87% of tumors in which mRNA for GH, PRL or TSH beta was detected and in only 17% of GH, PRL and TSH beta mRNA negative tumors. SF-1 mRNA was positive in 94% of tumors in which mRNA for FSH beta was present and in no FSH beta mRNA negative tumors. We conclude that RT-PCR analysis of hormone mRNA may be more sensitive than traditional hormone IHC for classification of pituitary tumors. Furthermore, tumor Pit-1 mRNA positively correlates with GH, PRL and TSH beta mRNA while tumor SF-1 mRNA correlates well with FSH beta mRNA. Combined analysis of hormone and transcription factor mRNA in pituitary tumor tissue may therefore be a more meaningful approach to pituitary tumor characterization.

DNA Primers↗