Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study shows that in the liver of the oviparous lizard, Podarcis s. sicula, the estrogen receptor (ER) level increases during the reproductive period (spring) when vitellogenesis occurs. This phenomenon interested both unfilled and filled ER present in the cytosolic and nuclear fractions. The increase in unfilled cytosolic and filled nuclear receptor was positively correlated to the plasma level of vitellogenin. The level of liver ER approximated that of mammalian liver ER and, therefore, it is higher than that reported for the liver of several nonmammalian species. At electrofocusing, liver ER distributes in two pH ranges (pH 6.5-7.5 and 8.0-8.8, respectively). The first form predominated in nuclei of reproductive females or of spayed estrogenized females and could represent the activated form of receptor. Ovariectomy was followed by a decrease in liver ER which can be induced in spayed females by estradiol administration. Pituitary growth hormone (GH) seemed to exert a synergic effect on estradiol liver estrogen receptor regulation. In lizards treated both with estradiol and GH, in fact, there was a significant increase in nuclear filled ER rather than an increase in the level of total nuclear ER.
Mol Cell Endocrinol 1989 Sep
PMID:Estradiol receptor in the lizard liver (Podarcis s. sicula). Seasonal changes and estradiol and growth hormone dependence. 258 61

Rat adenohypophyses lose immuno- and bioassayable growth hormone in hypothyroidism. We examined whether the somatotroph also loses mechanisms for intracellular hormone compartmentalization during hypothyroidism. A series of identical perifusions was performed using pituitary tissue from thyroidectomized rats before and after thyroxine replacement. Somatostatin (SRIF), (Bu)2cAMP and potassium ion were employed to produce a wide range of hormone release responses. Growth hormone synthesis diminished with hypothyroidism and increased with thyroid hormone replacement. Growth hormone release was therefore expressed as a percent of pituitary content to circumvent effects of variable content. Post-somatostatin rebound release was lost in hypothyroidism: it fell progressively after thyroidectomy (day 7 = 45% of control; day 14 = 11%; day 71 = 3%) and was restored by thyroxine replacement (day 2 = 24%; day 5 = 50%; day 9 = 102%). In conclusion, hypothyroid somatotrophs lose the ability to sequester stored hormone in a SRIF-sensitive compartment. Thyroxine replacement restores that capability. Thus, SRIF-sensitive rGH compartmentalization is thyroid hormone dependent.
Mol Cell Endocrinol 1986 Jan
PMID:SRIF-sensitive compartmentalization of stored rGH is abolished by hypothyroidism. 286 49

Growth hormone [GH] and prolactin [PRL] can be demonstrated simultaneously in electron micrographs by means of the double immunocytochemical labeling technique using colloidal gold particles of two different sizes. This method was used to study biopsy specimens obtained from 15 patients suffering from acromegaly, 11 patients suffering from prolactinomas, and eight biopsy specimens obtained during adenomectomy from the normal, paraadenomatous pituitary tissue. Four granule populations with different immunoreactions were found: (1) granules containing GH only, (2) granules containing PRL only, (3) mixed granules containing GH and PRL, and (4) granules displaying no immunoreactivity. The existence of mixed granules indicated that the two hormones are synthesized by the same cell and in communicating compartments of the cells; i.e., the rough-surfaced endoplasmic reticulum. The number of GH-containing granules (pure GH granules and mixed GH-PRL granules) was greater than that of PRL-containing granules (pure PRL granules and mixed PRL-GH granules) in adenomas causing acromegaly and in the normal pituitary tissue, whereas the opposite was true for prolactinomas. The number of PRL-containing granules was larger in biopsy specimens from patients who had acromegaly and hyperprolactinemia than in patients with acromegaly and normal serum PRL levels.
Virchows Arch B Cell Pathol Incl Mol Pathol 1987
PMID:Distribution of growth hormone and prolactin in secretory granules of the normal and neoplastic human adenohypophysis. 288 94

Three-month-old male Brattleboro rats with hereditary diabetes insipidus (DI) present a growth defect; Brattleboro rats were studied together with age-matched Long-Evans (LE) rats. Pituitary growth hormone (GH) content was comparable in both groups of rats. Pulsatile GH release and mean 6 h GH plasma levels did not appear significantly different in chronically catheterized DI and control animals. In parallel with the growth defect, the plasma somatomedin bioactivity was significantly lower in DI than in LE rats. The specific binding of [125I]iodo-hGH to liver microsomal membranes of DI rats was 59.7% that of controls. The number of the GH binding sites rather than the affinity of the binding was decreased. The specific binding of [125I]iodo-insulin was oppositely affected by the DI state: it was 1.5 times higher in liver membranes of DI rats than in membranes of LE rats. These findings make a non-specific effect of the DI state on liver membrane proteins unlikely. The Brattleboro rats present a growth failure without reduction of their GH secretion. The decreased number of the hepatic GH receptors and the subsequent low plasma somatomedin activity could explain the growth retardation of the DI rats.
Mol Cell Endocrinol 1986 Apr
PMID:The Brattleboro rat: normal growth hormone secretion, decreased hepatic growth hormone receptors and low plasma somatomedin activity. 300 48

The effect of adenohypophysial hormones on rat pineal melatonin content and release was examined in vitro. Medium concentration of radioimmunoassayable melatonin decreased after a 6 h exposure to 1-100 ng/ml FSH; pineal levels of melatonin were only decreased by 100 ng/ml FSH. LH (1-100 ng/ml) augmented significantly medium melatonin concentration, tissue levels being increased at 10 ng/ml LH. Parallel increases of explant and medium melatonin content were found after exposure to 1-100 ng/ml TSH. At the smallest concentration employed (1 ng/ml) prolactin increased melatonin content and release while at 100 ng/ml a significant depression of both parameters was found. Growth hormone (1-10 ng/ml) augmented melatonin levels in medium but failed to modify them at 100 ng/ml, although at this concentration tissue melatonin levels increased. ACTH did not modify pineal melatonin synthesis in vitro.
Mol Cell Endocrinol 1987 Mar
PMID:In vitro effects of adenohypophysial hormones on rat pineal melatonin content and release. 303 98

Stimulation of prolactin secretion by TRH probably involves mobilization of intracellular calcium to a greater extent than calcium influx, but less is known about the possible calcium-dependent mechanisms which may control prolactin gene transcription. We have studied this question in the rat pituitary tumour GH3 cell line by measuring prolactin mRNA accumulation by a cytoplasmic dot hybridization assay. Cobalt chloride, an intracellularly acting calcium antagonist, caused marked dose-dependent reductions in prolactin release and mRNA concentrations, whereas the calcium channel-blocking agent verapamil had no effect on prolactin release and had smaller effects on prolactin mRNA. Cobalt chloride abolished the stimulatory effect of TRH on prolactin mRNA levels, while verapamil caused only moderate inhibition. Growth hormone mRNA levels in the same cells were not significantly affected by TRH or verapamil, and only marginally reduced by cobalt. These data suggest that, as for prolactin release from normal rat pituitary lactotrophs, prolactin mRNA accumulation in GH3 cells appears to have a requirement for intracellular calcium which is only partly dependent upon calcium influx.
J Mol Endocrinol 1988 Sep
PMID:Calcium dependence of prolactin mRNA accumulation in GH3 rat pituitary tumour cells. 315 Dec 48

Growth hormone (GH) secretory patterns regulate the expression of several sex-dependent liver cytochrome P450 (CYP) genes. Studies using the hypophysectomized rat model have established that the intermittent plasma GH secretory pattern associated with adult male rats markedly stimulates liver expression of the male-specific CYP 2C11, a testosterone 2 alpha- and 16 alpha-hydroxylase, but is not required for expression of other male-specific liver enzymes, including CYP 2A2, a testosterone 15 alpha-hydroxylase, and CYP 3A2, a testosterone 6 beta-hydroxylase. In the present study, the effects of intermittent GH treatment on liver CYP expression were studied in adult rats rendered GH deficient by neonatal administration of monosodium glutamate (MSG), which depletes circulating adult GH without the global loss of other pituitary-dependent hormones that is associated with hypophysectomy. Restoration of the normal masculine circulating GH profile of six daily pulses (180-225 ng GH/ml/peak) in MSG-treated male rats by the use of an external pumping apparatus led to a substantial (30-50%) restoration of normal male levels of CYP 2A2 and CYP 3A2 activity, protein, and mRNA. GH pulsation at the nonphysiological frequencies of two or four times per day was less effective unless given at a dose that resulted in supraphysiological plasma GH levels. Although intermittent GH treatment can induce male-specific P450 expression in hypophysectomized female rats, the same hormone treatment did not stimulate CYP 2A2 or CYP 3A2 expression in MSG-treated female rats. Liver GH receptor mRNA levels at adulthood were not significantly altered by neonatal MSG treatment, suggesting that the unresponsiveness of MSG-treated females and the previously reported low responsiveness of MSG-treated males to GH-induced CYP 2C11 expression are not due to the absence of GH receptor. Moreover, normal liver IGF-1 mRNA levels were expressed in the MSG-treated female rats, suggesting that the liver GH receptor is functional in these animals. The present findings establish that the adult male-specific enzymes CYP 2A2 and CYP 3A2 can be positively regulated by intermittent GH pulsation despite their GH-independent expression in hypophysectomized rats. Moreover, neonatal MSG treatment, particularly in female rats, may lead to the loss of factors other than GH that are required for full expression of the pulsatile GH-stimulated CYP 2A2, 3A2, and 2C11 genes.
Mol Pharmacol 1995 Nov
PMID:Growth hormone regulation of male-specific rat liver P450s 2A2 and 3A2: induction by intermittent growth hormone pulses in male but not female rats rendered growth hormone deficient by neonatal monosodium glutamate. 747 8

Growth hormone releasing peptide (GHRP-6) is a synthetic hexapeptide which specifically stimulates secretion of growth hormone (GH) by pituitary somatotrophs. The precise intracellular mechanism by which this is achieved has not been deciphered although it is known to involve protein kinase C (PKC) and Ca2+ but to be cAMP-independent. We have used cell cultures of human pituitary somatotrophinomas to demonstrate powerful effects of GHRP-6 on membrane phosphatidylinositol (PI) turnover, a second messenger system which leads to activation of PKC and mobilisation of intracellular Ca2+ reserves. Incubation of somatotrophinoma cells with GHRP-6 led to a dose-dependent stimulation of rate of PI turnover. GH secretion was increased in parallel. Effects were discernable after only 15 minutes incubation and rose to a maximum at 2 hours. PI turnover was stimulated by GHRP-6 in 8 of 8 tumours examined, effects ranging from 2.1 - 7.9 fold increases. Stimulation of GH secretion by GHRP-6 was independent of presence of gsp oncogenes, emphasising the cAMP-independent nature of its effects. These results provide evidence that the GH-stimulatory effects of GHRP-6 are achieved through activation of the PI second messenger system and thus support earlier findings that PKC and Ca2+ play central roles in mediating the effects of GHRP-6.
J Mol Endocrinol 1995 Feb
PMID:Growth hormone releasing peptide (GHRP-6) stimulates phosphatidylinositol (PI) turnover in human pituitary somatotroph cells. 777 38

Pituitary growth hormone (GH) acts as a growth promoter in a wide range of tissues after binding to its specific GH receptor (GHR) or to a cytosolic circulating GH binding protein (GHBP). To further characterize GH target cells in the rat, in situ hybridization was used to investigate the tissue and cell distribution of mRNAs encoding GHR and GHBP, and their hepatic developmental expression was examined. Cryostat sections of adult male rat tissue were hybridized with [35S]dATP-labeled oligonucleotide antisense probes, one directed against a specific sequence of the intracellular domain of rat GHR mRNA, the other against the hydrophilic tail of rat GHBP mRNA. Several tests were carried out to validate the in situ detection of mRNA. Co-expression of the two transcripts in liver, spleen, thymus, kidney, adrenal, skin, muscle, heart, and pituitary was autoradiographically detected. However, relative expression levels, as demonstrated by computer-assisted microdensitometry, appeared to be variable. Both transcripts showed higher levels of expression in the liver, anterior and intermediate pituitary lobes, outer kidney medulla, adrenal cortex, skin epidermis, heart and muscle, but lower levels in spleen, thymus, hypodermis, adrenal medulla and posterior pituitary lobe. As a physiological control, hepatic levels of expression were examined during development, and the two forms of mRNA were found to be present at low levels in fetal liver, increasing considerably after birth. These results permit the identification in the adult male rat of cells that might be directly responsive to GH, and demonstrate the differential expression of rGHR and rGHBP transcripts.
Mol Cell Endocrinol 1995 Mar
PMID:In situ gene expression of growth hormone (GH) receptor and GH binding protein in adult male rat tissues. 778 15

The experimental system to scrutinize the in vitro proliferation of thymus epithelial cells (TECs) was established on the basis of enhancing their mitotic index and DNA synthetic activity. The TEC line, TAD3 derived from lymphocyte-dominant thymoma, was used as the cell material. Growth hormone (GH) induced a significant proliferation of the cultured cell line in the preconfluent state. The optimal concentration of and the duration of the incubation with GH, in this system, were 50 ng/ml and 18 hrs., respectively. Furthermore, insulin-like growth factor-I (IGF-I), the mediator of somatotropic action of GH, also enhanced the DNA synthetic activity of the cultured cells in the preconfluent state. The authors recently found that the TECs, stimulated with GH, released significantly more IGF-I than the cells without GH. It is possible that there are two systems in the TEC proliferation, namely, direct induction by GH itself and indirect induction by IGF-I released from the GH-stimulated TECs. The data showing that GH could directly or indirectly induce proliferation of TECs might possibly be related to the formation of epithelial thymic rudiment in the fetal stage.
Cell Mol Biol (Noisy-le-grand) 1994 Dec
PMID:The in vitro proliferation of thymus epithelial cells stimulated with growth hormone and insulin-like growth factor-I. 787 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>