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At least 415 records · Page 23Linked to original sources
PubMed1962

An immunologic study of two metabolically active peptides from the anterior pituitary gland.

Peptides I and II, two metabolically active peptides from porcine pituitary glands, stimulated antibody production in rabbits. The antiserum obtained had antibodies which interacted with peptides I and II from porcine pituitaries, peptides I and II from human pituitaries, and fraction H prepared by Rudman from hog pituitaries. None of the other pituitary preparations tested showed any interaction with peptides I and II. All three preparations stimulated the release of free fatty acids from rabbit adipose tissue in vitro. Antiserum inhibited this biological action to a different extent in each of the three preparations. Following an intravenous injection of peptides I and II there was a rapid rise in the plasma concentration of free fatty acids in rabbits. Injection of antiserum together with peptides I and II failed to block the rapid increase in free fatty acids. However, an injection of at least ten times the minimal amount of peptides I and II which raised the plasma free fatty acid concentration produced no increase in a rabbit with a high antibody titer to these peptides.

Adipose Tissue↗
PubMed1999

Papillary thyroid carcinoma metastatic to the pituitary gland.

Many malignancies may present with metastases to the pituitary gland. The association of thyroid carcinoma with pituitary metastases is, however, very rare. This report describes two patients in whom metastases from a papillary thyroid carcinoma to the pituitary gland resulted in panhypopituitarism with blunted endogenous thyrotropin (TSH) production following withdrawal of levothyroxine. Both required the use of recombinant human TSH prior to radioiodine therapy. Symptoms of hypopituitarism may be difficult to distinguish clinically from those of hypothyroidism in the setting of levothyroxine withdrawal. Clinicians should be aware of the clinical and biochemical manifestations of this rare association.

Carcinoma, Papillary↗
PubMed1987

In-vitro evidence for the autoregulation of prolactin secretion at the level of the pituitary gland in the rat.

The autoregulation of rat prolactin secretion at the level of the pituitary gland was investigated, using a static incubation system. The rate of prolactin secretion from the female anterior pituitary gland in vitro was found to be constant when the medium was changed at 20-min intervals. However, when the medium was left unchanged and secretory products were allowed to accumulate, prolactin secretion began to decline within 60 min. This effect was not observed with the male tissue, where the level of accumulated prolactin did not reach that at which the inhibition occurred using female tissue. The nature of the putative secretory product causing the inhibition of prolactin secretion was investigated. Exogenous bovine prolactin (1-4 mg/l) caused an inhibition of endogenous rat prolactin secretion. Inclusion of monoamine oxidase in unchanged medium, to prevent dopamine accumulation in the medium (a possible consequence of co-storage and co-secretion with prolactin granules), did not prevent the inhibition observed in the control incubation. We therefore conclude that in-vitro autoregulation of prolactin secretion can occur at the level of the pituitary gland, probably due to the accumulated prolactin having a feedback action on the lactotroph. This might be of physiological significance if localized concentrations of the hormone within the gland are high.

Animals↗
PubMed2005

The top 10 most abundant transcripts are sufficient to characterize the organs functional specificity: evidences from the cortex, hypothalamus and pituitary gland.

Using serial analysis of gene expression, we have identified the most abundant mRNA transcripts in parietal cortex, hypothalamus and pituitary gland in adult male mice. High mRNA abundance of neurogranin (cell signalling and communication) was characteristic of the cortex. The common molecular features of cortex and hypothalamus were high abundance of mRNA encoding mitochondrial enzymes such as reduced form of nicotinamide adenine dehydrogenase (NADH) 4 and cytochrome c oxidase 2 (energy metabolism), brain creatine kinase (energy metabolism) and myelin basic protein (cell structure). In the hypothalamus, mRNA levels of apolipoprotein E (lipid metabolism), prostaglandin D2 (cell signalling and communication) and secreted acidic cysteine-rich glycoprotein (extracellular matrix) were especially high. A common molecular feature of the hypothalamus and pituitary was high mRNA abundance of guanine nucleotide binding protein alpha stimulating complex locus (cell signalling and cell communication). The pituitary gland was characterized by high expression of genes encoding hormones such as growth hormone, pro-opiomelanocortin and prolactin, as well as neuronatin (cell differentiation) and four potential novel transcripts. Thus, these results show that the cortex, hypothalamus and pituitary gland can be specifically characterized according to their 10 most abundant transcripts. In addition, the current study serves as a basis for future studies on the potential novel transcripts and the transcripts with unclear functions despite their extremely high abundance, as well as studies on physiology and pathology of the two brain regions and pituitary gland.

Animals↗
PubMed1987

Enkephalins in the rat pituitary gland: immunohistochemical and biochemical observations.

The immunohistochemical distribution of opioid peptides derived from proenkephalin A in the rat pituitary was studied by indirect immunofluorescence; immunoreactive peptides were also characterized by column chromatography followed by specific RIAs. Nerve terminals in the neural lobe were immunoreactive (ir) for Tyr-Gly-Gly-Phe-Met-Arg-Phe (YGGFMRF), Tyr-Gly-Gly-Phe-Met-Arg-Gly-Leu (YGGFMRGL), and met-enkephalin [Tyr-Gly-Gly-Phe-Met (YGGFM)]. All cells in the intermediate lobe were ir for YGGFMRF, while only occasional cells exhibited YGGFMRGL-like immunoreactivity, and YGGFM-ir cells were not detected in this lobe. In the anterior lobe, some large ovoid cells, identified as gonadotrophs, were immunoreactive for enkephalins. The number of YGGFMRF-ir cells was larger than the number of YGGFMRGL- and YGGFM-ir cells, and these opioid peptides were present in cells that did not contain beta-endorphin immunoreactivity. Twenty times more YGGFMRF than YGGFMRGL-immunoreactivity was present in the anterior lobe, whereas the neurointermediate lobe obtained 4 times more ir YGGFMRF than YGGFMRGL. Pituitary lobe extracts contained substantial amounts of high mol wt forms of ir YGGFMRF and YGGFMRGL, but not of YGGFM or Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu). Low mol wt ir peptides present in both lobes consisted largely of the authentic peptides when analyzed by HPLC; however, an unidentified YGGFMRF-ir peptide was also detected. The results indicate that the proenkephalin A molecule may be processed differentially in the various compartments of the pituitary gland and that opioid peptides derived from this precursor may have functional roles in all three lobes. The relatively large amount of YGGFMRF immunoreactivity, which was detected both biochemically and immunohistochemically, indicates that YGGFMRF-ir peptides may be important proenkephalin A-derived products in the pituitary gland.

Animals↗
PubMed1999

Evaluation of the pituitary gland in idiopathic hypogonadotropic hypogonadism.

PURPOSE: Evaluation of the pituitary gland has been carried out in idiopathic hypogonadotropic hypogonadism (IHH) to test the potential of MR imaging in differentiating IHH patients from normals. MATERIAL AND METHODS: Thirty-seven patients (aged 18-30 years), and 20 volunteers (aged 20-30 years) were studied by T1-weighted MR imaging. Length (LA and LP), height (H), width (W), area (AA and AP), and volume (V1A, V1B V2A, V2P) of the pituitary gland were determined. (Subscripts P and A refer to measurements made with and without the posterior lobe, respectively.) V1 and V2 were estimated using two different methods. RESULTS: In the control group, LB W and V2A exhibited significant differences between female and male volunteers. While W was the only parameter that did not show significant difference between normals and patients (in both men and women), all other parameters except LB H and AP showed statistically significant differences between normals and IHH patients in both males and females. While LP was significantly different between normals and patients (men), H and AP were significantly different between normals and patients only in the female group. CONCLUSION: Correlation analysis between various parameters has shown that LA can be used for evaluating the pituitary in both the male and female IHH patients.

Adolescent↗
PubMed1994

Purification and characterization of gonadotropin I and II from pituitary glands of tuna (Thunnus obesus)

The duality of teleost pituitary gonadotropins was established in an advanced marine fish, the tuna (Thunnus obesus). Two different molecular forms of gonadotropins, designated tGTH I and tGTH II, were isolated from an alcoholic extract of pituitary glands following ion-exchange chromatography and reversed-phase HPLC. Both tGTH I and tGTH II stimulated estradiol-17 beta and testosterone production in tuna ovarian follicles in vitro, although responses to tGTH II were significantly greater than those to tGTH I. Each gonadotropin consisted of alpha- and beta-subunits. tGTH I was stable in acidic conditions, whereas tGTH II dissociated into two subunits after acid treatment. Alpha subunits of tGTH I and tGTH II had identical amino acid sequences of 94 amino acid residues. The tGTH I beta and tGTH II beta consisted of 102 and 115 amino acid residues, respectively, and showed 35% sequence identity. tGTH I beta is structurally more similar to salmon GTH I beta than to salmon GTH II beta, whereas tGTH II beta is more similar to salmon GTH II beta. Thus it is evident that the tuna pituitary gland produces two chemically distinct gonadotropins.

Amino Acid Sequence↗
PubMed2006

Thin-slice three-dimensional gradient-echo magnetic resonance imaging of the pituitary gland in healthy dogs.

OBJECTIVE: To evaluate thin-slice 3-dimensional gradient-echo (GE) magnetic resonance imaging (MRI) of the pituitary gland in healthy dogs. ANIMALS: 11 healthy dogs. PROCEDURES: By use of a 0.2-Tesla open magnet, MRI of the skull was performed with T1-weighted GE sequences and various protocols with variations in imaging plane, slice thickness, and flip angle before and after administration of contrast medium; multiplanar reconstructions were made. The pituitary region was subjectively assessed, and its dimensions were measured. Image quality was determined by calculation of contrast-to-noise and signal-to-noise ratios. RESULTS: Best-detailed images were obtained with a T1-weighted GE sequence with 1-mm slice thickness and 30 degrees flip angle before and after administration of contrast medium. Images with flip angles > 50 degrees were of poor quality. Quality of multiplanar reconstruction images with 1-mm slices was better than with 2-mm slices. The bright signal was best seen without contrast medium. With contrast medium, the dorsal border of the pituitary gland was clearly delineated, but lateral borders were more difficult to discern. CONCLUSIONS AND CLINICAL RELEVANCE: MRI of the canine pituitary gland with a 0.2-Tesla open magnet should include a T1-weighted GE sequence with 1-mm slice thickness and flip angle of 30 degrees before and after administration of contrast medium. The neurohypophysis was best visualized without contrast medium. The MRI examination permitted differentiation between the pituitary gland and surrounding structures.

Animals↗
PubMed1992

Bioregulatory role of the kallikrein-kinin system in the normal pituitary gland and its tumours.

Tissue kallikrein, a serine protease, is present in the prolactin-secreting cells of the normal anterior pituitary gland and pituitary adenomas. It is mainly located in the Golgi apparatus, but is also present in secretory granules. There is a distinct sexual dimorphism, with amount of tissue kallikrein being greater in anterior pituitary tissue from female rats. The intracellular levels of tissue kallikrein are increased by estradiol and in pituitary tumours, and decreased by ovariectomy, dopamine and its agonists. There is preliminary in vitro evidence that tissue kallikrein may be involved in the intracellular processing of the prolactin molecule before secretion. Tissue kallikrein synthesizes kinins which are present in the anterior pituitary and are capable of stimulating prolactin and growth hormone secretion by activating the phosphoinositide second messenger system. Prolactin physiology is uniquely linked to the kallikrein-kinin system in the normal pituitary and its tumours. Tissue kallikrein may have an important role in the pathophysiology of prolactin-secreting pituitary adenomas.

Adenoma↗
PubMed1976

Current adjuncts for surgery of the sphenoid sinus and pituitary gland.

Surgical intervention in the region of the sphenoid sinus pituitary gland requires extreme precision because of enveloping vital structures. The rhinologic approach to the pituitary gland, once abandoned due to limited visibility and the risk of meningitis, has experienced a renaissance as a result of recent medical and technical advances. Antibiotics have almost eliminated the risk of meningitis, and the operating microscope and televised radiofluoroscope now provide sufficient illumination, magnification, and orientation that injury to nearby structures can be avoided. A mid-line rhinologic approach provides ample exposure and further minimizes operative hazards.

Fluoroscopy↗
PubMed1984

Lectin target cells in human central nervous system and the pituitary gland.

Peanut lectin (PNL), Concanavalin A (Con A) and Ulex europaeus lectin I (Ulex) were chosen to map their binding sites in different regions of formalin fixed and paraffin embedded human central nervous system tissue and pituitary gland tissues. An extended PaP method was used for PNL and Ulex, whereas a direct peroxidase technique was employed for Con A. In astrocytes, the cytoplasm as well as the delicate processes were stained by PNL and Con A; the most conspicuous binding of PNL was seen in the ependymal cells and on the surface of plexus epithelial cells; in the anterior part of the pituitary gland a selective population was PNL positive. Intracytoplasmic Con A acceptors could be demonstrated in neurons, in ependymal cells, and in plexus epithelial cells. Intracytoplasmic Con A receptors were finely granular in astrocytes, oligodendrocytes, and in some cells in the pituitary gland. Ulex binding was restricted to the vascular endothelial cells and a selective population of cells in the pituitary gland. Our results suggest that lectins may be good tools for the evaluation of their respective target cells in the central nervous system and in the pituitary gland.

Arachis↗
PubMed1975

Vinblastine-induced microtubular paracrystals in prolactin cells of anterior pituitary gland of lactating rats.

Vinblastine sulfate in physiological saline was injected directly into the pituitary glands of lactating rats. Injections were made through the ear canal using a syringe equipped with a 24-gauge needle. The animals were killed at 2, 4, or 6 hours after the injections. When the anterior pituitary glands were examined by electron microscopy, many microtubular paracrystalline deposits were seen in the prolactin and growth hormone cells. The usual cytoplasmic microtubules and microfilaments were not seen in the cytoplasm of these cells. Granular extrusion (exocytosis) was markedly depressed, and an accumulation of secretory granules was definitely observed in the prolactin cells after the administration of vinblastine.

Animals↗
PubMed1985

Formation of ester forms of riboflavin in the pituitary gland of rat.

We studied the formation of ester forms of riboflavin in the pituitary gland of rats using 14C-riboflavin labeling and a gel filtration technique. The active formation of ester fraction of riboflavin suggests that two synthesizing enzymes of ester forms, flavokinase and FAD pyrophosphorylase, exist in this organ. A minor peak containing a lesser amount of radioactivity contained protein as measured by UV absorption at 280 nm was found when supernatant from incubated homogenate was chromatographed on a Sephadex G-15 column. This suggests the presence of a riboflavin-binding protein; the amount of 14C-riboflavin bound to pituitary proteins was expressed as the binding capacity of riboflavin. No changes were found in the binding capacity or esterification of riboflavin in the pituitary gland of rats treated with ACTH, dexamethasone phosphate, or subjected to liver impairment by CC14 injection. However, esterification was increased at 24 and 48 h after adrenalectomy. We posit that the riboflavin turnover in the pituitary gland may not be subject to marked changes in order to maintain the function of this organ. In aged rats, esterification was lower than in young rats suggesting that the turnover of pituitary riboflavin is related to senescent phenomena.

Adrenalectomy↗
PubMed2004

Herpes simplex virus types 1 and 2 infect the mouse pituitary gland and induce apoptotic cell death.

Herpes simplex virus (HSV) infected the anterior lobe of the pituitary gland resulting in cytopathic changes following intravenous (i.v.) inoculation of male mice. Both HSV type 1 (HSV-1) and type 2 (HSV-2) were isolated from pituitary gland following i.v. infection, but not after intraperitoneal inoculation. HSV-infected pituitary cells were microscopically visible beginning at 24 h or 48 h following i.v. inoculation and were localized in the anterior pituitary. In both HSV-1 and -2 infections the pituitary lesions were apoptotic, as determined by light and electron microscopy, TUNEL, and DNA gel electrophoresis. However, the pituitary infection does not appear to be life-threatening since pituitary lesions were also observed following i.v. infection with HSV-1 strain -GC which possesses low virulence. These results suggest that the pituitary gland is one of the target organs of HSV infection.

Animals↗
PubMed1995

Normal MR appearance of the pituitary gland in the first 2 years of life.

PURPOSE: To investigate changes in the size, shape, and signal intensity of the pituitary gland during the first 2 years of life. METHODS: One hundred consecutive MR studies, spin-echo T1- and T2-weighted sequences, of children 0 to 2 years of age were analyzed. Signal intensity and shape of the gland were graded and its signal intensity measured. RESULTS: There was a statistically significant difference in the signal intensity of both the anterior and posterior pituitary gland and in the shape between children younger than and older than 6 weeks of age and younger than and older than 27 weeks of age. There were definite trends in the size of the gland with age (decrease in height and increase in anteroposterior diameter and width). CONCLUSIONS: There are changes in the pituitary gland in the newborn period that may reflect the ongoing changes in pituitary hormones reported to occur during this time.

Child Development↗
PubMed1989

Metastatic carcinoma to the pituitary gland.

Four patients with metastatic carcinoma to the pituitary gland are presented. Two of these patients had no previous history of malignancy and, based on clinical, laboratory, and radiological evaluation, a preoperative diagnosis of pituitary adenoma was made. In one patient, the histological diagnosis of two consecutive tumour specimens, obtained 1 year apart, was pituitary adenoma. The correct diagnosis of metastatic renal-cell carcinoma was not ascertained until autopsy. In the second patient, a diffusely infiltrating breast carcinoma was diagnosed by mammography and confirmed by biopsy, after pathological examination of the sellar tumour revealed carcinoma. The third patient underwent mastectomy 3 years earlier for breast carcinoma and had known metastatic disease. The fourth patient had known metastatic endometrial carcinoma when she became symptomatic from a pituitary metastasis. The incidence, clinical features, and pathophysiology of metastatic carcinoma to the pituitary gland are discussed.

Adult↗