Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of nerve growth factor (NGF) on induction of Na+,K+-ATPase were examined in a rat pheochromocytoma cell line, PC12h. Na+,K+-ATPase activity in a crude particulate fraction from the cells increased from 0.37 +/- 0.02 (n = 19) to 0.55 +/- 0.02 (n = 20) (means +/- SEM, mumol Pi/min/mg of protein) when cultured with NGF for 5-11 days. The increase caused by NGF was prevented by addition of specific anti-NGF antibodies. Epidermal growth factor and insulin had only a small effect on induction of Na+,K+-ATPase. A concentration of basic fibroblast growth factor three times higher than that of NGF showed a similar potency to NGF. The molecular form of the enzyme was judged as only the alpha form in both the untreated and the NGF-treated cells by a simple pattern of low-affinity interaction with cardiotonic steroids: inhibition of enzyme activity by strophanthidin (Ki approximately 1 mM) and inhibition of Rb+ uptake by ouabain (Ki approximately 100 microM). As a consequence, during differentiation of PC12h cells to neuron-like cells, NGF increases the alpha form of Na+,K+-ATPase, but does not induce the alpha(+) form of the enzyme, which has a high sensitivity for cardiotonic steroid and is a characteristic form in neurons.
 ...
PMID:Nerve growth factor induces Na+,K+-ATPase in a nerve cell line. 244 35

Epidermal growth factor (EGF) is known to stimulate proliferation of various mammalian cells and secretion of prolactin (PRL) from rat anterior pituitary tumor cells. The effect of an acute increase in serum PRL induced by thyrotropin releasing hormone (TRH) or metoclopramide (MCP) on the serum immunoreactive EGF concentration was examined in nine hyperprolactinemic patients and eight normoprolactinemic women. The basal level of serum EGF in normoprolactinemic subjects was 472.8 +/- 51.1 pg/ml (Mean +/- SEM), which was not significantly different from that in hyperprolactinemic patients (487.8 +/- 22.5 pg/ml). The serum EGF concentration was decreased to 40-50% of the basal level after the abrupt increase in serum PRL induced by the injection of TRH or MCP in normoprolactinemic subjects, but no significant change in serum EGF occurred in hyperprolactinemic patients after MCP injection, in spite of a significant increase in PRL. These results suggest that an acute increase of serum PRL in normoprolactinemic women, but not in hyperprolactinemic patients, suppresses serum EGF.
 ...
PMID:Suppression of serum immunoreactive human epidermal growth factor by acute increase in prolactin in women. 250 3

Epidermal growth factor (EGF), dehydroepiandrosterone (DHA)-sulphate and [Na+] and [K+] were assayed in 78 cyst fluids from patients with a palpable breast cyst. Epidermal growth factor was detected in all but 2 cysts, the mean value +/- SEM being 506.2 +/- 39.3 ng/ml, with a range of 0-1,599 ng/ml. When the cyst fluids were sub-divided according to their [Na+]:[K+] ratio, group A cyst fluids ( [Na+]:[K+] less than 3) had a significantly higher (p less than 0.001) level of EGF than group B cyst fluids ([Na+]:[K+] greater than 3). Furthermore, the relationship between EGF and [Na+] and [K+] and between EGF and DHA-sulphate seemed to differ between the 2 cyst types and each cyst type was therefore analyzed separately.
 ...
PMID:Quantification of epidermal growth factor in human breast cyst fluids: correlation with dehydroepiandrosterone-sulphate and electrolyte concentrations. 252 6

Specific receptors for insulin-like growth factor I (IGF-I) on cultured human choriocarcinoma cells (JEG-3 and BeWo) were characterized. The binding of 125I-labeled recombinant (Thr59)IGF-I to the cells was reversible and time, temperature, and pH dependent. Steady state of binding occurred after 16 h at 4 C, pH 7.4. Natural human IGF-I (hIGF-I), hIGF-II, recombinant (N-Met)IGF-I, rat multiplication-stimulating activity, and insulin were 200%, 37%, 37%, 1.6%, and 0.1% as potent as (Thr59)IGF-I in inhibiting the binding of [125I]iodo-(Thr59)IGF-I to JEG-3 cells, respectively. Epidermal growth factor was ineffective. The half-maximal displacement of [125I]iodo-(Thr59)IGF-I by unlabeled (Thr59)IGF-I occurred at 11 +/- 2 ng/ml (mean +/- SEM) in both JEG-3 and BeWo cells. Scatchard analysis of the competitive binding data revealed linear plots indicating a single species of binding sites with an association constant of 0.8 X 10(9) M-1 for the binding of [125I]iodo-(Thr59)IGF-I to both cell lines. The binding capacity was 30,000 and 20,000 sites/cell for JEG-3 and BeWo cells, respectively. Chemical cross-linking of [125I]iodo-(Thr59)IGF-I to JEG-3 cells revealed two receptor complexes of 130K and 260K. Their formation was completely inhibited by an excess of unlabeled (Thr59)IGF-I or hIGF-II. Increasing amounts of insulin affected both labeled bands equally, suggesting that the 130K and 260K bands represent the monomer and dimer forms, respectively, of the ligand-binding alpha-subunit of type I IGF receptor. (Thr59)IGF-I, in a dose-dependent manner, stimulated uptake of nonmetabolizable alpha-[3H]aminoisobutyric acid by JEG-3 cells, showing that the receptor is biologically active. Our results demonstrate that choriocarcinoma cells possess functional high affinity type I IGF receptors and suggest that IGF-I is involved in the growth-regulating processes of JEG-3 and BeWo cells. These cells may provide a useful model to study the role of IGFs in trophoblast physiology.
 ...
PMID:Characterization of functional type I insulin-like growth factor receptors from human choriocarcinoma cells. 296 49

Epidermal growth factor (EGF) stimulates granulosa cell (GC) proliferation of certain species and modulates FSH-induced GC differentiation. The present study was undertaken to characterize the binding properties of the EGF receptor in porcine GCs to determine if the EGF responsiveness of mitotically active porcine GCs was related to their differentiated state and was regulated by reproductive hormones in vitro. Characterization of the EGF receptor-binding properties of porcine GCs revealed that saturation binding was achieved with 10 ng/ml [125I]iodo-EGF after 1 h at 37 C. In all states of differentiation, porcine GCs expressed few (less than 20,000/cell), specific, high affinity EGF receptors with apparent Kd values of 5.5 +/- 0.7 X 10(-10) M (mean +/- SEM; n = 6). Freshly harvested GCs obtained from small follicles were considered slightly differentiated (SDs) and bound, on the average, 2.6-fold more [125I]iodo-EGF than highly differentiated cells (HDs) obtained from large follicles which had further differentiated in vivo. The difference in binding was due to a decrease in receptor number and not to a change in receptor affinity. This relationship observed in freshly harvested cells was maintained in culture for a limited period. At 48 h of culture, the [125I]iodo-EGF-binding capacity of SDs was higher than that of HDs and was inversely related to the state of differentiation, as measured by [125I]iodo-LH/hCG-binding capacity. After 96 h, however, the EGF-binding capacity of HDs increased 3.7-fold from the level of binding at 48 h, while the LH/hCG-binding capacity decreased 10-fold. Conversely, the EGF-binding capacity of SDs decreased 28%, while the LH/hCG-binding capacity remained low. These experiments indicated that the state of GC differentiation was inversely correlated with EGF receptor number and that this relationship was not maintained in culture beyond 48 h. FSH treatment within the first 48 h of culture decreased the EGF-binding capacity of SDs 35% relative to the control value, but estradiol and dihydrotestosterone had no effect. FSH also regulated the mitotic responsiveness to EGF. EGF treatment of cultured SDs stimulated an 84% increase in cell number and a 178% increase in [3H]thymidine incorporation. These effects were suppressed by a high concentration of FSH. Thus, the ability of porcine GCs to bind EGF was changed with differentiation in vivo, while both EGF-binding capacity and mitotic responsiveness were regulated by exposure to FSH in vitro.
 ...
PMID:[125I]iodo-epidermal growth factor binding and mitotic responsiveness of porcine granulosa cells are modulated by differentiation and follicle-stimulating hormone. 312 Dec 83

Epidermal growth factor (EGF) receptors on primary-cultured human thyroid cells from 27 neoplasias (nine adenomas and 18 differentiated carcinomas) were analyzed and compared with those on the cultured nonneoplastic part of human thyroid cells. Total binding of 125I-EGF to the nonneoplastic part, adenoma, and carcinoma cells did not differ significantly. Scatchard analysis showed that the neoplastic human thyroid cells, like their adjacent nonneoplastic counterparts, consistently possessed EGF receptors with two components. In a paired study of five patients, the association constant of the carcinoma cells' high-affinity component (Ka1) was found to be significantly lower than that of adjacent nonneoplastic thyroid cells (P less than 0.05). Furthermore, a study of the cells from 18 carcinomas revealed that overall their Ka1s (4.15 +/- 0.82 x 10(9) M-1, mean +/- SEM) were significantly lower than those of adenoma cells (10.34 +/- 1.51 x 10(9) M-1, n = 9) and of nonneoplastic cells adjacent to them (8.32 +/- 0.84 x 10(9) M-1, n = 23). The difference in Ka1s for adenoma and nonneoplastic thyroid cells was not statistically significant. The number of receptor sites (Cmax) per cell was not significantly different in any of the three. Incorporation of [3H]thymidine (dThd) increased significantly in all kinds of thyroid cells examined following the addition of 10 nM EGF, and the paired study showed that the size of this increase was not significantly different in neoplastic and adjacent nonneoplastic cells. The addition of 300 microunits/ml of thyroid-stimulating hormone caused a significant increase in dThd incorporation by adenoma cells but not by carcinoma or nonneoplastic cells. Furthermore, combined treatment with EGF and thyroid-stimulating hormone additively promoted adenoma cell growth only. A close inverse relationship was observed between Ka1 and the stimulatory effect of EGF on the dThd uptake in both nonneoplastic thyroid cells and adenoma cells. Carcinoma cells also showed similar profiles, but Ka1 relative to dThd increases were much smaller than the other two.
 ...
PMID:Epidermal growth factor receptors on cultured neoplastic human thyroid cells and effects of epidermal growth factor and thyroid-stimulating hormone on their growth. 325 6

Epidermal growth factor (EGF) stimulated prostacyclin (PGI2) production by cultured human umbilical vein endothelial cells, as measured by radioimmunoassay of its stable metabolite 6-keto-prostaglandin F1 alpha. This effect of EGF was dose-dependent, the lowest stimulatory concentration of EGF was 1.0 ng/ml and 100 ng/ml caused a 2.7 +/- 0.3 (mean +/- SEM) fold increase in the PGI2 synthesis. The stimulation appeared at 3-6 h of incubation and lasted at least 24 h. It was suppressed by EGF antibodies and blocked by protein synthesis inhibitor cycloheximide. Cells preincubated 12 h with EGF released also higher amounts of PGI2 when incubated with thrombin for 5 min. It is concluded that EGF liberated from platelets during aggregation may prevent local thrombogenesis and atherogenesis by stimulating the release of the antiaggregatory, vasodilatory PGI2 from vascular endothelial cells.
 ...
PMID:Epidermal growth factor stimulates prostacyclin production by cultured human vascular endothelial cells. 329 Nov 83

Epidermal growth factor receptors are present in many reproductive tissues but have not been demonstrated in the human corpus luteum. To determine the presence of epidermal growth factor receptors and its binding characteristics, we carried out studies on the plasma cell membrane fraction of seven human corpora lutea (days 16 to 25) of the menstrual cycle. Specific epidermal growth factor receptors were present in human corpus luteum. Insulin, nerve growth factor, and human chorionic gonadotropin did not competitively displace epidermal growth factor binding. The optimal conditions for corpus luteum-epidermal growth factor receptor binding were found to be incubation for 2 hours at 4 degrees C with 500 micrograms plasma membrane protein and 140 femtomol 125I-epidermal growth factor per incubate. The number (mean +/- SEM) of epidermal growth factor binding sites was 12.34 +/- 2.99 X 10(-19) mol/micrograms protein; the dissociation constant was 2.26 +/- 0.56 X 10(-9) mol/L; the association constant was 0.59 +/- 0.12 X 10(9) L/mol. In two regressing corpora lutea obtained on days 2 and 3 of the menstrual cycle, there was no detectable specific epidermal growth factor receptor binding activity. Similarly no epidermal growth factor receptor binding activity could be detected in ovarian stromal tissue. Our findings demonstrate that specific receptors for epidermal growth factor are present in the human corpus luteum. The physiologic significance of epidermal growth factor receptors in human corpus luteum is unknown, but epidermal growth factor may be involved in intragonadal regulation of luteal function.
 ...
PMID:Human corpus luteum: presence of epidermal growth factor receptors and binding characteristics. 349 79

Epidermal growth factor (EGF) is a small polypeptide with potent mitogenic activity. Its synthesis by mouse submaxillary gland is stimulated by certain hormones. To assess its physiological significance in man, we have developed a homologous radioimmunoassay for human epidermal growth factor (hEGF) in saliva. A satisfactory standard curve was readily obtained using either buffer or peptide-free saliva. The mean IC50 was 436 +/- 200 pM (mean +/- SD) and sensitivity approximately 35 pM. The mean normal salivary hEGF in 63 males was 314.6 +/- 21.7 pM (+/- SEM) and 354 +/- 27.8 pM in 48 females. The difference between the means of the sexes was not significant. Assays of aliquots stored under different conditions showed hEGF in saliva to be stable and the method reproducible. Salivary hEGF secretion did not suggest diurnal rhythmicity and was unrelated to meals.
 ...
PMID:Homologous radioimmunoassay for epidermal growth factor in human saliva. 387 83

Epidermal growth factor-like activity (EGF-LA) has been detected in human seminal plasma in concentrations of 5-150 ngeq/ml (36.4 +/- 2.1, mean +/- SEM), using a heterologous RRA with murine EGF. The samples were obtained from normal, subfertile and azoospermic men, aged 21-50 yr. No correlation was found between EGF concentration and age of donor, sperm count, sperm motility, or period of sexual abstinence before sample collection. High performance liquid chromatography of the seminal plasma resulted in a main peak of EGF-LA which eluted at 29% acetonitrile, compared to 33% for murine EGF. Microsomal membranes were prepared from several tissues from the human male reproductive tract and were tested for their ability to bind radioiodinated murine EGF. Specific EGF binding activity was detectable in testicular membrane preparations but was not detectable in membranes prepared from human prostate, seminal vesicle, epididymis, or spermatozoa. Endogenous EGF-LA was detectable in human testis, seminal vesicle, prostate, and epididymis.
 ...
PMID:Identification of epidermal growth factor-like activity in human male reproductive tissues and fluids. 632 31


1 2 3 Next >>