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At least 253 records · Page 14Linked to original sources
PubMed1981

Cross-reactivity between human and fish pituitary hormones as demonstrated by immunocytochemistry.

In this communication we describe the immunocytochemical cross-reactivity between antisera to various human pituitary hormones and specific hormone producing cell types in the pituitary gland of sexually mature male platyfish (Xiphophorus maculatus). Antisera to human pituitary hormones cross-reacted either with cells known to produce corresponding hormones (or hormone subunits) in the platyfish (e.g., ACTH, prolactin, TSH beta, LH alpha, FSH alpha, TSH alpha) or with no pituitary cells at all (e.g., HL beta, FSH beta). The one exception was antiserum to human growth hormone which cross-reacted with MSH and ACTH producing cells. The platyfish pituitary is proposed as a test system for immunocytochemically screening antisera for purity and specificity in order to determine their applicability in particular studies.

Animals↗
PubMed1992

Effects of pituitary hormones on the cell-specific expression of the KAP gene.

The expression of kidney androgen-regulated protein (KAP) gene in mouse kidney is regulated in a multihormonal fashion. As determined by in situ hybridization analysis, epithelial cells of proximal convoluted tubules of cortical nephrons express KAP mRNA in response to androgenic stimulation while similar cells in the juxtamedullary S3 segment of the tubules express KAP mRNA under estrogenic and pituitary hormonal control. In situ hybridization analysis of kidney sections using hypophysectomized (hypox) mice resulted in a total absence of KAP mRNA suggesting the participation of a pituitary hormone(s) in the constitutive expression of KAP mRNA in S3 cells. Treatment of hypox mice with steroid hormones showed that androgens restored the ability of cortical tubule cells to synthesize KAP mRNA. Estrogen treatment, on the other hand, partially induced KAP gene expression only in S3 cells. These results indicated that the androgenic response of the gene is independent of pituitary function, while expression in S3 cells, although partially induced by the direct action of estrogens, is primarily regulated by a pituitary factor. In order to elucidate which hormone(s) is responsible for KAP gene expression in S3 cells, individual pituitary hormones were administered to hypox normal animals and to strains of mice genetically deficient in certain pituitary hormones. Surgically treated C57BL/6 female and male mice were implanted for 7 days with osmotic pumps containing individual pituitary hormones, after which the kidneys were analyzed by in situ hybridization. Mice injected with growth hormone (GH), corticotropin (ACTH), prolactin (PRL), or vehicle failed to express KAP mRNA. Mice treated with thyrotropin (TSH), follitropin (FSH), and lutropin (LH) exhibited high levels of KAP mRNA in S3 cells of females as well as in the renal cortex of male animals. Expression in the cortex in response to LH and FSH may be due to their gonadotropic effect on testosterone production. Similarly, contamination of TSH samples with small amounts of the gonadotropins may explain the cortical response to TSH. TSH produced the strongest response in S3 cells suggesting that it is responsible for the permissive effect of the pituitary on KAP gene expression. This conclusion was supported by studies performed with the dwarf mouse (dw/dw) which lacks PRL, GH, and TSH due to a mutation in the pit-1 gene. In situ hybridization analysis of dwarf mice kidney sections showed a complete lack of KAP gene expression. The possible participation of GH and PRL was eliminated on the basis of the hormone replacement studies.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenocorticotropic Hormone↗
PubMed2002

The effects of dopamine and D2 receptor antagonists on pituitary hormone secretion are intact in mice lacking dopamine D2L receptor.

The dopamine D2 receptor (D2) is involved in the regulation of pituitary hormone secretion. Two isoforms of the D2 receptor, termed D2L and D2S, have been identified. We previously generated D2L knockout mice (D2L-/-), which still express D2S. The present study examined the role of D2S and D2L in spontaneous and drug-induced pituitary hormone secretion. We found that D2L-/- mice had normal serum levels of prolactin and growth hormone. In addition, the antipsychotic drugs haloperidol and clozapine induced a similar dose-dependent increase in serum prolactin in both D2L-/- and wild-type mice. These results suggest that D2S can substitute for the function of D2L in the regulation of pituitary hormone secretion, and that the function of D2S is not dependent on the formation of a receptor heterodimer with D2L.

Animals↗
PubMed1985

[Anterior pituitary hormone in severe head injury--with special reference to the GH, TSH, LH and FSH response to TRH and LH-RH].

Measurement of the serum level of anterior pituitary hormones (GH, TSH, LH and FSH) and the response of these hormones to their releasing hormones were made in 45 uncomplicated head injury patients within 24 hours after injury. We classified these 45 patients into three groups according to the Glasgow Outcome Scale of six months after head injury, such as good outcome group (GR or MD), poor outcome group (SD or PVS) and dead group. The serum level of the anterior pituitary hormones in dead group were higher than those in the good or poor outcome group, especially the level of GH. The serum level of GH was 14.7 +/- 3.0 ng/ml in the dead group, whereas 5.8 +/- 0.9 ng/ml in the good outcome group and 4.0 +/- 2.1 ng/ml in the poor outcome group. The response of TSH, LH or FSH to the administration of TRH or LH-RH were depressed in the dead group. On the other hand, there were normal response of TSH, LH or FSH following administration of TRH or LH-RH in the other two survival groups. These findings suggested that the measurement of the anterior pituitary hormones and the response of these hormones to their releasing hormones were useful to evaluate the severity of head injury.

Adolescent↗
PubMed2002

Biosynthesis and secretion of pituitary hormones: dynamics and regulation.

Production and secretion of hormones by the pituitary involve highly orchestrated intracellular transport and sorting steps. Hormone precursors are routed through a series of compartments before being packaged in secretory granules. These highly dynamic carriers play crucial roles in both prohormone processing and peptide exocytosis. We have employed the ACTH-secreting AtT-20 cell line to study the membrane sorting events that confer functionality (prohormone activation and regulated exocytosis) to these secretory carriers. The unique ability of granules to promote prohormone processing is attributed to their acidic interior. Using a novel avidin-targeted fluorescence ratio imaging technique, we have found that the trans-Golgi of live AtT-20 cells maintains a mildly acidic (approximately pH 6.2) interior. Budding of secretory granules causes the lumen to acidify to <pH 6.0, which is both necessary and sufficient to trigger SPC3-mediated proteolytic conversion of proopiomelanocortin to ACTH. Investigation of the pH regulatory mechanism indicates that the trans-Golgi and secretory granules maintain different pH values by distinct sorting of key membrane transporters. Mathematical modeling of our data suggests that the decreasing pH values of organelles of the regulated secretory pathway is established by gradually increasing the density of active H+ pumps from the ER to Golgi while concomitantly decreasing the H+ permeability from ER to Golgi to secretory granules. An in vitro assay was developed to study the formation of processing-competent secretory granules from their processing-incompetent precursor trans-Golgi compartment. Our data suggest that ARF1-mediated sorting of proton pumps and leaks during early stages of granule formation confers processing competency to the resulting organelle. Once formed, these young granules continue to undergo membrane remodeling which results in dynamic changes in their exocytotic behavior. Two SNAREs, VAMP4 and synaptotagmin IV, enter newly formed granules but are removed from the maturing granule membrane by vesicle budding. Sorting of these proteins is correlated with the acquisition of Ca2+-triggered exocytosis and a decrease in unregulated exocytotic rate. Thus, biosynthesis and secretion of pituitary hormones are dynamically regulated by intracellular sorting events that govern the functions of their secretory carriers.

Animals↗
PubMed1994

Four patients with polyendocrinopathy with associated pituitary hormone deficiency.

Four cases of polyglandular endocrine disorders associated with pituitary hormone secretion failure are reported. Three of them had both insulin dependent diabetes mellitus (IDDM) and Hashimoto's disease. Each of these patients (cases 1-3) showed isolated deficiency of ACTH, TSH or gonadotropin, respectively. Another patient (case 4) had both Hashimoto's disease and isolated ACTH deficiency. Anti-pituitary antibody to AtT-20 cells was detected in case 1. Serum gamma-globulins from patients 1 and 4 attenuated corticotropin releasing hormone-induced ACTH release in monolayer cultured rat anterior pituitary cells. Gamma-globulins from patients 1 and 2 decreased baseline TSH release but stimulated baseline prolactin release in pituitary cell cultures. It is possible that pituitary hormone deficiency in these patients may be caused by autoimmune disorders.

Adrenocorticotropic Hormone↗
PubMed1980

Changes of pituitary hormones in brain death.

In six patients with clinical and electroencephalographic signs of brain death, pituitary hormones such as prolactin, human growth hormone (GH), luteinizing hormone (LH), and thyrotrophin (TSH) were measured in blood close to the demonstration of intracranial circulatory arrest by angiography. In addition, pituitary hormone releasing tests and an insulin test were carried out in two patients. The results showed that no patient had a general decrease in hormone levels, according to their biological half life times, which suggests there still was some function in the hypothalamus and pituitary. This was supported by the results of the stimulation tests. It is concluded that in brain death some basal parts of the brain may still be perfused despite the fact that angiography indicates circulatory arrest in these areas.

Adolescent↗
PubMed1984

Effect of growth hormone (GH)-releasing hormone (GRH) on plasma GH in relation to magnitude and duration of GH deficiency in 26 children and adults with isolated GH deficiency or multiple pituitary hormone deficiencies: evidence for hypothalamic GRH deficiency.

Synthetic, amidated, 44 amino acid GH-releasing hormone ( GRH -44) was administered iv at a dose of 5 micrograms/kg to 20 patients with severe GH deficiency (GHD), 6 children and adolescents with partial GHD, and 6 non-GH deficient ( NGHD ) children and adolescents. The 17 patients with severe GHD that responded to GRH -44 had lower peak concentrations of plasma GH than the NGHD individuals (5.0 +/- 1.2 (SEM) vs. 27.2 +/- 3.5 ng/ml; P less than 0.0001). The children and adolescents with severe GHD tended to have higher peak GH responses to GRH -44 than the GHD adults (6.9 +/- 1.7 vs. 2.4 +/- 0.3 ng/ml) although the difference was not significant. The peak GH concentration was attained earlier in the GHD children and adolescents than in the GHD adults (28 +/- 4.7 vs. 69.3 +/- 13 min, P less than 0.004). There was a negative correlation between chronological age and peak plasma GH response to GRH in the children and adolescents with severe GHD (r = -0.758, P less than 0.02). Children and adolescents with partial GHD had a higher mean peak concentration of plasma GH (13. 1 +/- 1.8 ng/ml) than the children, adolescents, and adults with severe GHD (P less than 0.04), but one lower than the NGHD children and adolescents (P less than 0.05). In both severe and partial GHD the GH response to GRH was greater than that elicited by standard pharmacological tests. Serum somatomedin-C did not increase after a single pulse of GRH -44 in the 12 GHD patients studied. PRL increased minimally 30 min after 5 micrograms/kg iv GRH -44 in patients with multiple hypothalamic-pituitary hormone deficiencies but not in patients with isolated GHD or in NGHD individuals. The GH responses to GRH suggest that the majority of patients with isolated GHD as well as those with multiple hypothalamic-pituitary hormone deficiencies have deficiency of hypothalamic GRH . Lack of a GH response to a single pulse of GRH does not exclude GRH deficiency as priming of the somatotrope with multiple pulses of GRH may be necessary to rule out a hypothalamic defect in the nonresponders. The results of this study support the potential usefulness of GRH or its analogs in the diagnosis and treatment of selected patients with disorders of GH secretion.

Adolescent↗
PubMed1985

The effect of nicardipine on pituitary hormone release in normal volunteers.

In a double-blind, placebo-controlled, randomised, cross-over study of six healthy male subjects, the effect of nicardipine (5 mg h-1 for 3 h) on basal and stimulated pituitary hormone release was examined. Statistically significant differences between nicardipine and placebo were seen occasionally for follicle-stimulating hormone, luteinising hormone and prolactin, but not for thyroid-stimulating hormone. These differences were always within the between-batch coefficient of variation of the assay. The overall differences in both basal and stimulated results for all four pituitary hormones were not statistically significantly different. It is concluded, therefore, that nicardipine has no significant effect on either basal or stimulated pituitary hormone release in healthy male subjects.

Adult↗
PubMedDate not supplied

Actions of ethanol on hypothalamic and pituitary hormones in prepubertal female rats.

To determine the effects of prepubertal ethanol (ETOH) exposure on hypothalamic and pituitary hormones known to be involved in the onset of female puberty, we have chronically exposed female rats to either a liquid-diet containing ETOH or an isocaloric control liquid-diet. An additional set of controls consisted of animals maintained on Lab Chow, and water provided ad lib. Our results indicate that the feeding regimen employed produced no differences with regard to body and reproductive organ weights, as well as any of the hormones measured between the two control groups. Conversely, ETOH-treated animals showed significantly lower body and reproductive organ weights than the control animals and although no differences were detected between ETOH-treated and control animals with regard to the hypothalamic content of somatostatin (SRIF), there was a significant increase in the hypothalamic content of growth hormone releasing hormone (GHRH), with a concomitant and significant decrease in the serum concentration of growth hormone (GH). Furthermore, the ETOH-treated animals showed a significant increase in the hypothalamic content of luteinizing hormone releasing hormone (LHRH) with a significant decrease in the serum concentration of luteinizing hormone (LH), but not follicle stimulating hormone (FSH). These results demonstrate for the first time that chronic, prepubertal ETOH administration alters the concentrations of specific hypothalamic and pituitary hormones which are known to be involved in the female pubertal process.

Animals↗
PubMed1988

Participation of voltage-sensitive calcium channels in pituitary hormone release.

The role of extracellular Ca2+ in pituitary hormone release was studied in primary cultures of rat anterior pituitary cells. The basal levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyrotropin (TSH), and adrenocorticotropin (ACTH) secretion were independent of extracellular Ca2+ concentration ([Ca2+]e). In contrast, the basal levels of growth hormone (GH) and prolactin (PRL) release showed dose-dependent increases with elevation of [Ca2+]e, and were abolished by Ca2+-channel antagonists. Under Ca2+-deficient conditions, BaCl2 mimicked the effects of calcium on PRL and GH release but with a marked increase in potency, and also increased basal LH and FSH release in a dose-dependent manner. In the presence of normal [Ca2+]e, depolarization with K+ maximally increased cytosolic [Ca2+] ([Ca2+]i) from 100 to 185 nM and elevated LH, FSH, TSH, ACTH, PRL, and GH release by 7-, 5-, 4-, 3-, 2-, and 1.5-fold, respectively. These effects of KCl were abolished in Ca2+-deficient medium or in the presence of the Ca2+-channel antagonist, Co2+, and were diminished by the dihydropyridine Ca2+-channel antagonist, nifedipine. The Ca2+-channel agonist BK 8644 (100 nM) enhanced the hormone-releasing actions of 25 mM KCl upon PRL, LH, FSH, GH, TSH, and ACTH by 2.3-, 2.0-, 1.8-, 1.7-, 1.6-, and 1.4-fold, respectively. The dose- and voltage-dependent actions of BK 8644 were specific for individual cell types; BK 8644 enhanced GH, PRL, TSH, LH, and ACTH secretion in the absence of any depolarizing stimulus, with ED50 values of 8, 10, 150, 200, and 400 nM, respectively. However, in the presence of 50 mM KCl, the ED50 values for BK 8644 were 1.5, 2, 3, 5, and 7 nM for GH, PRL, ACTH, TSH, and LH, respectively. [3H]BK 8644 bound specifically to pituitary membranes with Kd values of 0.8 nM and concentrations of about 900 channels per cell. These observations provide evidence for the presence and participation of voltage-sensitive calcium channels in the secretion of all five populations of anterior pituitary cells.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1985

Pituitary 5-hydroxytryptamine nerves--a possible link with pituitary hormone secretion.

A short review of the present knowledge on the innervation of the pituitary gland by 5-hydroxytryptamine (5-HT) containing nerves is given. This is followed by results of recent experiments in which the concentrations of 5-HT in different lobes of the rat hypophysis were measured under conditions in which pituitary hormone secretion was increased. A prolonged increase in hormone secretion induced by dehydration and increased sodium chloride intake resulted in a decrease in the 5-HT concentrations in the anterior lobe (AL). The 5-HT content of the neural (NL) and the intermediate lobe (IL) of these rats was hardly changed whereas that of DA was about doubled. Acute stimulation of pituitary hormone secretion by exsanguination under ether anaesthesia also caused a fall in the 5-HT content of the AL. In contrast, in the NL and in the IL of these rats, the 5-HT concentrations were significantly increased. This indicates that the 5-HT system in the AL reacts differently from those in the NL and IL. Pituitary dopamine (DA) contents were not affected by ether and exsanguination. Thus, the pituitary DA and the pituitary 5-HT neuronal systems are activated independently in different endocrine states. The concentrations of 5-HT were also measured in 10 groups of normal male or female rats in the course of 2 years and compared with those of DA. The concentrations of 5-HT were lowest in the AL with little variation between the different groups. In the rest of the tubero-hypophyseal system the concentrations of 5-HT were at least 3, and up to 10 times, higher than in the AL, with larger inter group variations. The DA concentrations in the AL were only 10-20% of those of 5-HT; in the other regions they were equal to or higher than those of 5-HT.

Acute Disease↗
PubMed1999

Combined pituitary hormone deficiency in an inbred Brazilian kindred associated with a mutation in the PROP-1 gene.

Mutations in the pituitary-specific paired-like homeodomain transcription factor PROP-1 result in combined pituitary hormone deficiency (CPHD) which includes all anterior pituitary hormones with the exception of ACTH. In an inbred pedigree with CPHD, direct sequencing of the PROP-1 gene revealed a deletion of two base pairs (301-302delAG) in exon 2, resulting in a frameshift and a premature stop in codon 109 in the homeodomain. The clinical characteristics of this family support the notion that this truncation results in a more severe phenotype than missense mutations in the aminoterminal part of the homeodomain.

Adult↗