Antimicrobial activity of bovine ß-lactoglobulin against mastitis-causing bacteria.

Bovine mastitis is one of the most economically deleterious diseases affecting dairy herds and results from an infection of the udder by pathogenic microorganisms such as Staphylococcus aureus, Streptococcus uberis, and Escherichia coli. The mammary gland is capable of preventing and combating bacterial infection by means of a complex network of innate and adaptive immune mechanisms. Lactoferrin is an 86-kDa protein with antibacterial activity that plays a role in the mammary gland's defense against infection. ß-Lactoglobulin (ß-LG) is an 18-kDa protein that is present in most mammals but is notably absent in humans, rodents, and lagomorphs. Different genetic variants of this protein exist, with ß-LG A and ß-LG B being the most common. In spite of being well studied, the biological function of ß-LG is not thoroughly understood, and most noticeably, no reports exist on the effects of the native protein on bacterial growth. Hence, the objective of this study was to assess the potential antibacterial activity of ß-LG against mastitis agents. To do this, we purified ß-LG from normal bovine milk using a mild, nondenaturing method and performed in vitro growth inhibition assays with Staph. aureus, E. coli, and Strep. uberis. ß-Lactoglobulin inhibited the growth of Staph. aureus and Strep. uberis but had no effect on E. coli. The antimicrobial activity against Staph. aureus and Strep. uberis was concentration dependent and was elicited by the intact protein because Tricine-sodium dodecyl sulfate-PAGE and analytical gel filtration chromatography did not reveal the presence of short degradation peptides. Analysis of the genetic variants of ß-LG showed that ß-LG A has higher inhibitory activity against Staph. aureus and Strep. uberis than ß-LG B. Coincubation of ß-LG and lactoferrin resulted in an augmented antibacterial activity against Staph. aureus, suggesting an additive effect of the proteins. This result, along with the proteins' complementary spectrum of action, suggests that ß-LG and lactoferrin may complement each other in the mammary gland's defenses against bacterial infection.

Foot Eczema in a Skin Allergy Unit: Retrospective Study of 13 Years. / Eczema en los pies en una consulta de alergia cutánea: estudio retrospectivo de 13 años.

INTRODUCTION: Foot eczema is a common complaint encountered by skin allergists. OBJECTIVE: To study a series of patients with foot eczema who underwent patch testing and describe their demographic profile, diagnoses, and the main allergens involved. MATERIAL AND METHODS: Cross-sectional observational study of all patients tested with the standard Spanish patch test series at a dermatology department over a period of 13 years (2004-2016). We studied patch test results and definitive diagnoses by comparing different subgroups of patients with foot eczema. RESULTS: Of the 3,265 patients included in the study, 308 (9.4%) had foot eczema, 176 (57.9%) had foot eczema only and 132 (42.1%) had concomitant foot and hand eczema. Positive patch test results were more common in patients with foot eczema only (positivity rate of 61.5% vs. 53.4% for foot and hand eczema). In the subgroup of patients with concomitant foot and hand involvement, patients aged under 18 years had a lower rate of positive results (51.3% vs. 64.6% for patients >18 years). Potassium dichromate was the most common allergen with current relevance in all subgroups. The main diagnosis in patients with foot involvement only was allergic contact dermatitis (49.1%). In the subgroup of patients with concomitant hand and foot eczema, the main diagnoses were psoriasis in adults (33.6%) and atopic dermatitis in patients aged under 18 years (60.0%). CONCLUSION: Patch tests are a very useful diagnostic tool for patients with foot eczema with or without concomitant hand involvement.

ACTH and prostaglandin receptors in human adrenocortical tumors. Apparent modification of a specific component of the ACTH-binding site.

The failure of certain adrenal tumors to respond to ACTH was investigated in vivo be administration of corticotropin-(1-24)-tetracosapeptide (ACTH1-24) and dexamethasone and in vitro by studying the binding properties of ACTH1-24 and prostaglandin E1 (PGE1) and their effect on adenylate cyclase activity of the tumors' crude membranes; in addition, in five cases the stimulation of cortisol production in isolated adrenal cells by both hormones and dibuttyryl cyclic adenosine 3',5'-monophosphate (cAMP) was also studied. The results obtained in 13 hormone-producing tumors of the human adrenal cortex, i.e. 10 carcinomas and 3 adenomas, were compared with those found in normal human adrenal glands. According to the adenylate cyclase responses to ACTH1-24 and PGE1, the tumors fall into different categories. In the first group are six rumors in which the adenylate cyclase was stimulated by both ACTH1-24 and PGE; in addition specific binding could be demonstrated for the two hormones in all six. The binding affinity for 125I-ACTH1-24 was found to be about 10 times higher than that for 125I-ACTH11-24. In the one tumor in which the experiment was performed, bound 125I-ACTH1-24 was displaced by ACTH1-10. These results are similar to the ones found in normal human adrenal preparations. For two rumors of the group in which ACTH did not increase steroidogenesis in vivo, the biochemical abnormality might be located beyond cAMP formation. A second group encompasses six tumors in which the steroidogenesis in vivo and the adenylate cyclase activity were insensitive to ACTH1-24 but in which the enzyme was stimulated by PGE1 and NaF. However, these preparations bound 125I-ACTH1-24 and 125I-ACTH11-24, the binding affinity being similar for both peptides but 10 times lower than the one found in normal adrenal cortex for 125I-ACTH1-24. In the only case of this group where it was tested, ACTH1-10 did not displace bound 125I-ACTH1-24. This result strongly suggests the possibility of a modification or a loss of the receptor site that binds the N-terminal sequency (1-10) of ACTH, the biologically active part of the molecule. In the last tumor, both PGE1 and ACTH were unable to stimulate adenylate cyclase activity and steroid production in a preparation of isolated adrenal cells, although steroidogenesis was stimulated by dibutyryl though steroidogenesis was stimulated by dibutyryl cAMP. No specific binding for PGE1 could be demonstrated. However, 125I-ACTH1-24 and 125I-ACTH11-24 were found to be bound to the tumor with the same affinity.

Gap junction-mediated cell-to-cell communication in bovine and human adrenal cells. A process whereby cells increase their responsiveness to physiological corticotropin concentrations.

We have studied the role of gap junction-mediated intercellular communication on the steroidogenic response of bovine (BAC) and human (HAC) adrenal fasciculo-reticularis cells in culture to corticotropin (ACTH). Indirect immunofluorescence analyses showed that intact human and bovine adreno-cortical tissue as well as HAC and BAC in culture expressed the gap junction protein connexin43 (also termed alpha 1 connexin). Both HAC and BAC were functionally coupled through gap junctions as demonstrated by microinjection of a low molecular mass fluorescent probe, Lucifer yellow. The cell-to-cell transfer of the probe was blocked by 18 alpha-glycyrrhetinic acid (GA), an inhibitor of gap junction-mediated intercellular communication. GA markedly decreased the steroidogenic response (cortisol production) of both HAC and BAC to low (10 pM) but not to high (5 nM) concentrations of ACTH. GA had no inhibitory effect on the steroidogenic response to 8 Br-cAMP (at either low or high concentrations) and did neither modify the binding of 125I-ACTH to its receptor nor the ACTH-induced cAMP production. BAC cultured at high or low cell densities (2.4 x 10(5) vs. 0.24 x 10(5) cells/cm2) exhibited distinct levels of intercellular communication and were differently responsive to sub-maximal ACTH concentrations. The ACTH ED50 values for cortisol production were 8.5 +/- 1.3 and 45 +/- 14 pM (P < 0.02) for BAC cultured at high and low density, respectively. In the presence of GA, there was a shift of the ACTH concentration-response curves in the two culture conditions. The ACTH ED50 of high density and low density cultured BAC increased 25- and 5-fold, respectively, and became similar (220 +/- 90 and 250 +/- 120 pM). These results demonstrate that gap junction-mediated communication between hormone-responsive and nonresponsive cells is one mechanism by which adrenal cells increase their responsiveness to low ACTH concentrations.

Regulation of corticotropin receptor number and messenger RNA in cultured human adrenocortical cells by corticotropin and angiotensin II.

The regulation of ACTH receptor binding sites and mRNA by ACTH and angiotensin II (A-II) was studied using cultured human adrenal fasciculata reticularis cells (HAC). These cells expressed two major ACTH receptor transcripts of 1.8 and 3.4 kb and three minor ones of 4, 7, and 11 kb. ACTH increased the levels of all these transcripts in a time- and dose-dependent manner. At a maximal concentration of 10(-8) M, ACTH enhanced 21- and 4-fold the level of ACTH receptor mRNA and the number of receptors per cell, respectively. Pretreatment of HAC with A-II produced a dose-dependent enhancement of ACTH receptor mRNA that was associated with an increase of both ACTH receptor number and responsiveness to this hormone. The effects of A-II were completely blocked by an AT1 receptor subtype antagonist but not by an AT2 antagonist. The effects of ACTH together with A-II on ACTH receptor mRNA were greater than those induced by each hormone alone. These results show that ACTH receptor number and mRNA are positively regulated by the two main hormones (ACTH and A-II) which, in vivo, regulate adrenocortical functions. In addition, they also show that HAC are a target for A-II. Thus, regulation of ACTH receptors may be one mechanism by which ACTH and A-II regulate adrenocortical functions under both normal and pathological conditions.

Metabolic clearance rate and blood production rate of testosterone and dihydrotestosterone in normal subjects, during pregnancy, and in hyperthyroidism.

The metabolic clearance rate (MCR) and blood production rate (BP) of testosterone (T) and dihydrotestosterone (DHT), the conversion of plasma testosterone to plasma dihydrotestosterone, and the renal clearance of androstenedione, testosterone, and dihydrotestosterone have been studied in man. In eight normal men, the MCR(T) (516+/-108 [SD] liters/m(2)/day) was significantly greater than the MCR(DHT) (391+/-71 [SD] liters/m(2)/day). In seven females, the MCR(T) (304+/-53 [SD] liters/m(2)/day) was also greater than the MCR(DHT) (209+/-45 [SD] liters/m(2)/day) and both values were less than their respective values in men (P < 0.001). In men the conversion of testosterone into dihydrotestosterone at 2.8+/-0.3% (SD) was greater than that found in females, 1.56+/-0.5% (SD) (P < 0.001). In five pregnant females the MCR(T) (192+/-36 [SD] liters/m(2)/day), the MCR(DHT) (89+/-30 [SD] liters/m(2)/day) and the conversion of testosterone into dihydrotestosterone (0.72+/-0.15%) (SD) were significantly less than the values found in nonpregnant women. In five females with hyperthyroidism, the MCR for testosterone and dihydrotestosterone were similar to those observed in pregnant females, but the conversion of testosterone into dihydrotestosterone (2.78+/-1.7%) (SD) was greater, and similar to that found in men. In men the production of dihydrotestosterone was 0.39+/-0.1 (SD) mg/day, 50% being derived from the transformation of plasma testosterone. In women the production of DHT was 0.05+/-0.028 (SD) mg/day, only 10% coming from testosterone. During pregnancy, the production of testosterone and dihydrotestosterone are similar to that in normal women. In three patients with testicular feminization syndrome (an adult with hyperthyroidism and two children) these two MCRs were greatly reduced compared to the normal females, but the conversion of testosterone into dihydrotestosterone was in the limits of normal male rangeIn the normal subjects the renal clearance of androstenedione was greater than that of testosterone and dihydrotestosterone. Less than 20% of the dihydrotestosterone and less than 10% of the androstenedione in the urine is derived from the plasma dihydrotestosterone and androstenedione.

Glucocorticoid-suppressible hyperaldosteronism and adrenal tumors occurring in a single French pedigree.

Glucocorticoid-suppressible hyperaldosteronism is a dominantly inherited form of hypertension believed to be caused by the presence of a hybrid CYP11B1/CYP11B2 gene which has arisen from an unequal crossing over between the two CYP11B genes in a previous meiosis. We have studied a French pedigree with seven affected individuals in which two affected individuals also have adrenal tumors and two others have micronodular adrenal hyperplasia. One of the adrenal tumors and the surrounding adrenal tissue has been removed, giving a rare opportunity to study the regulation and action of the hybrid gene causing the disease. The hybrid CYP11B gene was demonstrated to be expressed at higher levels than either CYP11B1 or CYP11B2 in the cortex of the adrenal by RT-PCR and Northern blot analysis. In situ hybridization showed that both CYP11B1 and the hybrid gene were expressed in all three zones of the cortex. In cell culture experiments hybrid gene expression was stimulated by ACTH leading to increased production of aldosterone and the hybrid steroids characteristic of glucocorticoid-suppressible hyperaldosteronism. The genetic basis of the adrenal pathologies in this family is not known but may be related to the duplication causing the hyperaldosteronism.

Spanish consensus for the management of patients with anaplastic cell thyroid carcinoma.

Anaplastic thyroid cancer (ATC) is the most aggressive solid tumor and almost uniformly lethal in humans. The Boards of the Thyroid Cancer Group of the Spanish Society of Endocrinology and Nutrition and the Grupo Español de Enfermedades Huérfanas e Infrecuentes of the Spanish Society of Oncology requested that an independent task force draft a more comprehensive consensus statement regarding ATC. All relevant literature was reviewed, including serial PubMed searches together with additional articles. This is the first, comprehensive Spanish consensus statement for ATC and includes the characteristics, diagnosis, initial evaluation, treatment goals, recommendations and modalities for locoregional and advanced disease, palliative care options, surveillance, and long-term monitoring. Newer systemic therapies are being investigated, but more effective combinations are needed to improve patient outcomes. Though more aggressive radiotherapy has reduced locoregional recurrences, median overall survival has not improved in more than 50 years.

Consensus on the management of advanced radioactive iodine-refractory differentiated thyroid cancer on behalf of the Spanish Society of Endocrinology Thyroid Cancer Working Group (GTSEEN) and Spanish Rare Cancer Working Group (GETHI).

Thyroid cancer is the single most prevalent endocrine malignancy; differentiated thyroid cancer (DTC) accounts for more than 90 % of all malignancies and its incidence has been rising steadily. For more patients, surgical treatment, radioactive iodine (RAI) ablation, and thyroid-stimulating hormone (TSH) suppressive therapy achieve an overall survival (OS) rate of 97.7 % at 5 years. Nevertheless, locoregional recurrence occurs in up to 20 % and distant metastases in approximately 10 % at 10 years. Two-thirds of these patients will never be cured with radioactive iodine therapy and will become RAI-refractory, with a 3-year OS rate of less than 50 %. Over the last decade, substantial progress has been made in the management of RAI-refractory DTC. Given the controversy in some areas, the Spanish Task Force for Thyroid Cancer on behalf of Spanish Society of Endocrinology Thyroid Cancer Working Group (GTSEEN) and the Spanish Rare Cancer Working Group (GETHI) have created a national joint task force to reach a consensus addressing the most challenging aspects of management in these patients. In this way, multidisciplinary management should be mandatory and nuclear medicine targeted therapy, novel molecular targeted agents, and combinations are currently changing the natural history of RAI-refractory DTC.

Consensus on management of advanced medullary thyroid carcinoma on behalf of the Working Group of Thyroid Cancer of the Spanish Society of Endocrinology (SEEN) and the Spanish Task Force Group for Orphan and Infrequent Tumors (GETHI).

BACKGROUND: Of all thyroid cancers, <5 % are medullary (MTC). It is a well-characterized neuroendocrine tumor arising from calcitonin-secreting C cells, and RET gene plays a central role on its pathogeny. METHODS: The electronic search was conducted using MEDLINE (PubMed), EMBASE and Cochrane Central Register of Controlled Trials. Quality assessments of selected current articles, guidelines and reviews of MTC were performed. RESULTS: This consensus updates and summarizes biology, treatment and prognostic considerations of MTC. CONCLUSIONS: Multidisciplinary teams and specialized centers are recommended for the management of MTC patients. In the metastatic setting, those patients with large volume of disease are candidates to start systemic treatment mainly if they are symptomatic and the tumor has progressed in the last 12-14 months. Wait and see strategy should be offered to patients with: disseminated disease with only high levels of calcitonin and no macroscopic structural disease, low burden and absence of progression.

Tumor necrosis factor system activity is associated with insulin resistance and dyslipidemia in myotonic dystrophy.

Myotonic dystrophy (MyD) is a multisystem autosomal dominant disorder associated with progressive muscle wasting and weakness. The striking metabolic abnormality in MyD is insulin resistance. The mechanism by which target tissues are insensitive to insulin action remains uncertain. In a recent study, plasma soluble tumor necrosis factor receptor (sTNFR)2 levels were found to be associated with muscle tissue mass and insulin resistance. Given these associations, we speculated that disorders of the muscle cell membrane could lead simultaneously to insulin insensitivity and sTNFR2 leakage in MyD. To test this hypothesis, we measured the levels of circulating sTNFR1 and sTNFR2 and insulin resistance in MyD patients. We studied 22 MyD patients and 24 age-, BMI-, and fat mass-matched control subjects. Both MyD men and women showed higher plasma insulin levels in the presence of comparable glucose concentrations than did control subjects. sTNFR2, but not sTNFR1, levels were approximately 1.5-fold higher in MyD patients. In parallel with these findings, the fasting insulin resistance index (FIRI) was also higher in MyD patients. In fact, in the whole population, fasting insulin and FIRI strongly correlated with sTNFR2 in both men (r = 0.77 and r = 0.81, P<0.0001, respectively) and women (r = 0.67 and r = 0.64, P = 0.001, respectively). sTNFR2 levels were also associated with the insulin sensitivity index (S(I)), calculated from an oral glucose tolerance test (OGTT) according to the method by Cederholm and Wibell (r = -0.43, P = 0.006). We constructed a multiple linear regression to predict FIRI, with BMI, waist-to-hip ratio, and sTNFR2 as independent variables. In this model, both BMI (P = 0.0014) and sTNFR2 (P = 0.0048) levels contributed independently to 46% of the variance of FIRI. In another model, in which FIRI was substituted for S(I) from the OGTT, both BMI (P = 0.0001) and sTNFR2 (P = 0.04) levels contributed independently to 48% of the variance of S(I) from the OGTT. Plasma cholesterol and triglyceride concentrations were significantly increased in MyD patients. sTNFR1 and sTNFR2 levels were found to be strongly associated with plasma cholesterol, LDL cholesterol, and triglycerides. sTNFR1 and sTNFR2 also correlated with serum creatine kinase activity in MyD patients (r = 0.57, P = 0.006; r = 0.75, P<0.0001, respectively). In conclusion, here we describe, for the first time to our knowledge, a relationship between insulin action and plasma sTNFR2 concentration in MyD patients. We have also found increased concentrations of plasma triglycerides and cholesterol levels in parallel with sTNFR1 and sTNFR2 concentrations in MyD patients. We speculate that the latter associations are dependent on, and secondary to, increased tumor necrosis factor (TNF)-alpha action. Whether TNF action is implicated in the pathogenesis of MyD or is a simple marker of disease activity awaits further studies.

Growth hormone and insulin-like growth factor I treatment increase testicular luteinizing hormone receptors and steroidogenic responsiveness of growth hormone deficient dwarf mice.

To test the hypothesis that insulin-like growth factor (IGF-I) is required for the in vivo development of testicular Leydig cell function, either recombinant human GH [(hGH) (1.5 micrograms/g BW) or recombinant IGF-I (1 microgram/g BW) was injected three times daily into immature Snell dwarf mice (dw/dw) and into phenotypically normal control (Dw/-) for 7 days. In dw/dw mice hGH enhanced significantly body, liver, kidney, and testicular weight. In addition, hGH increased testicular LH receptors and the acute steroidogenic response to human CG, but there was no significant effect on basal plasma testosterone or plasma LH levels. The effects of IGF-I in body and kidney weight were less pronounced than those produced by hGH, but its effects on testicular weight and LH receptors, as well as on the acute steroidogenic response to human CG, were similar to that observed after hGH treatment. In Dw/- mice hGH had no effect on either body or organ weight or on testicular function, despite the fact that it induced a significant increase in plasma IGF-I levels. These results indicated that IGF-I is able to induce the maturation of Leydig cell function and that the effects of hGH on the testis are probably mediated by IGF-I. They also suggest that the delayed puberty associated with GH deficiency or resistance is most likely related to an IGF-I deficiency.

Processing of angiotensin II (A-II) and (Sar1,Ala8)A-II by cultured bovine adrenocortical cells.

Bovine adrenocortical cells, cultured in a chemically defined medium, were used to study the fate of [125I] iodoangiotensin II ([125I]iodo-A-II) and its antagonist (Sar1,Ala8)A-II ([125I]iodo-Saralasin). The binding of both ligands was time and temperature dependent. The maximum specific binding at 37 C, which was reached within 1 h, was followed by a decline with a half-life of about 2 h and 8 h for [125I]iodo-A-II and [125I]iodo-Saralasin, respectively. The decrease of the specific binding was parallel to the appearance in the medium of degraded ligand. At 4 C, the binding of [125I]iodo-A-II was stable for 12 h and no degradation of ligand occurred. Under several experimental conditions, about 70% of the total [125I]iodo-A-II bound was internalized, whereas, in the case of [125I]iodo-Saralasin, less than 25% of the total bound ligand was internalized. These differences in the binding kinetics between A-II and its antagonist were mainly the differences in the rate of internalization of the bound ligands, more rapid for [125I]iodo-A-II (t1/2 approximately equal to 10 min) than for [125I]iodo-Saralasin (t1/2 = 90 min). On the other hand, the rate of degradation of internalized ligand was similar for both ligands (t1/2 = 15 min). Ionophore monensin enhanced the total cellular uptake of both ligands by increasing the amount of internalized ligands. Monensin did not modify the rate of internalization of the two ligands but markedly decreased their rate of degradation (t1/2 approximately equal to 60 min). These results indicate that both A-II and its antagonist are internalized and degraded by adrenocortical cells, but the rate of internalization of the antagonist is lower than that of the agonist. They also show that receptor-mediated endocytosis is the main pathway by which A-II is rapidly degraded by adrenocortical cells. Since A-II receptors are present in many tissues, the receptor-mediated degradation could explain the very short half-life in plasma of this hormone.

Steroidogenesis of cultured purified pig Leydig cells: effects of lipoproteins and human chorionic gonadotropin.

Dispersed Leydig cells were prepared from pig testes and purified in a discontinuous Percoll gradient. About 95% of these cells stained for 3 beta-hydroxysteroid dehydrogenase. The cells were cultured in a chemically defined medium. Testosterone production was low (2 +/- 0.4 ng/10(6) cells/day) under basal conditions, but increased by 8- to 10-fold on the third day of daily human CG (hCG) treatment. Addition to the medium of both human and pig low density lipoprotein (LDL) produced a dramatic increase in both basal (8-fold) and acute hCG-stimulated (5-fold) testosterone production, whereas both human and pig high density lipoprotein were far less effective. Furthermore the effect of lipoproteins was synergistic with that of hCG. The effects of human LDL on both basal and hCG-stimulated testosterone productions were dose-dependent. Maximum effect was achieved at a protein concentration of 10-40 micrograms/ml with an ED50 of about 4 micrograms/ml. Three days of pretreatment with hCG or (Bu)2cAMP alone induced Leydig cell steroidogenic refractoriness to both hCG and (Bu)2cAMP stimulation. Concomitant treatment with LDL restored the steroidogenic capacity, but only partially. Production of pregnenolone and testosterone of desensitized cells was significantly higher than that of control cells under basal conditions, but was 60% and 40% lower, respectively, after acute hCG stimulation. Moreover, the conversion of exogenous pregnenolone to testosterone by desensitized cells was only 60% of that of control cells. These results show that the de novo synthesis of cholesterol is able to account for only 25% of the maximal steroidogenic capacity of pig Leydig cells and that hCG-induced steroidogenic desensitization is only partially due to cholesterol depletion.

Opposite effects of ACTH and glucocorticoids on adrenal DNA synthesis in vivo.

Administration of ACTH to rapidly growing weanling rats results in an increase of DNA synthesis in adrenal and a decrease in liver. Dexamethasone administration decreases both adrenal and liver DNA synthesis. When both hormones were administered to the same animals, the liver DNA synthesis was similar to that observed with dexamethasone alone, but the DNA synthesis in adrenal was lower than that obtained with ACTH alone, yet higher than that observed with dexamethasone. The plasma levels of corticosterone were similar in animals treated with ACTH or with ACTH plus dexamethasone. Aminoglutethimide stimulated adrenal DNA synthesis, but less than ACTH. This substance overcame partially the inhibitory effects of dexamethasone on liver DNA synthesis but did not in adrenal. When both ACTH and aminoglutethimide were given simultaneously, adrenal DNA synthesis was higher than that observed with each substance alone. In all experiments in which adrenal cytosol DNA polymerase was studied, the activity varied in the same direction as DNA synthesis. These results indicate opposing effects of ACTH and glucocorticoids on adrenal DNA synthesis. The finding of a glucocorticoid effect on the adrenal is supported by the demonstration of a glucocorticoid specific binding protein in adrenal cytosol. Cycloheximide blocks the stimulatory action of ACTH on both steroidogenesis and DNA synthesis. Actinomycin D, as well as dexamethasone, blocks only the DNA synthesis-promoting action of ACTH. This latter result suggests some differences in the metabolic pathways by which ACTH controls steroidogenesis and growth in the adrenal cell.

Identification and characterization of angiotensin-II receptor subtypes in cultured bovine and human adrenal fasciculata cells and PC12W cells.

Angiotensin-II (Ang II) receptor subtypes (AT1 and AT2) were analyzed in bovine adrenal cells (BAC) by binding and cross-linking experiments using [125I]Ang II and [125I]CGP42112, a specific ligand of AT2 receptors. [125I]Ang II binding was reduced by 80% and 20% in the presence of maximal concentrations of the AT1 antagonist losartan (DuP 753) and CGP42112, respectively, whereas [125I]CGP42112 binding was inhibited by Ang II or CGP42112, but not by losartan. In the presence of the reducing agent dithio-1,4-erythritol, the binding of [125I] CGP42112 was increased 2-fold; this was due to an increase in the binding affinity (Kd, 8 +/- 4 x 10(-10) vs. 4.8 +/- 1.2 x 10(-10) M). Cross-linking of [125I]Ang II to BAC in the presence of disuccinimidyl suberate, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed a band of 70,000 +/- 8,000 mol wt (M(r)) under both reducing and nonreducing conditions. This band disappeared when the incubation was performed in the presence of 10(-6) M Ang II or 5 x 10(-8) M CGP42112, but not in the presence of 10(-5) M losartan. Dithio-1,4-erythritol (10 mM) markedly enhanced the band. After cross-linking with 1,5-difluoro-2,4-dinitrobenzene and solubilization of the cells in the presence of protease inhibitors, two radioactive bands were observed with M(r) of 70,000 and 50,000. The first disappeared after the addition of Ang II or CGP42112, whereas the second disappeared in the presence of Ang II or losartan, but not in the presence of CGP42112. Cross-linking of [125I]AngII to either human adrenal fasciculata-reticularis cells, which contain only AT1 sites, or COS-7 cells transfected with human AT1 cDNA revealed a major band of 50,000 M(r) that was blunted by Ang II or losartan, but not by CGP42112. Moreover, cross-linking of [125I]Ang II to PC12W cells, which contain only the AT2 receptor subtype, revealed a single radioactive band of 70,000 Mr that was blunted by CGP42112 but not by losartan. Thus, in both BAC and PC12W cells, the AT2 receptor has a M(r) of 70,000, whereas the AT1 receptor in BAC, human adrenal cells, and cells transfected with human AT1 receptor cDNA has a Mr of 50,000. Therefore, the heterogeneity of the size of the Ang II receptor previously reported after photoaffinity or cross-linking was probably due to only to a variation in the degree of glycosylation between tissues and species, but also to the presence of two different receptor subtypes.

In vitro maturation of steroidogenic capacity of ovine fetal and neonatal adrenal cells.

The in vitro production of total corticosteroids, corticosterone (B), and cortisol (F) by cultured adrenocortical cells from fetuses (115-120 days old) and newborn lambs exposed to ACTH-(1-24) was investigated in relation to the time of culture. Corticosteroids were measured by using an antibody against F, whereas B and F separately were each assayed by specific antibodies after their separation by thin layer chromatography. Basal corticosteroid production by fetal cells increased about 5-fold between days 1 and 6 of culture, whereas the production of B and F increased from 3 +/- (SE) 0.3 to 194 +/- 25 and 3.9 +/- 0.3 to 17.4 +/- 1.9 [ng (8 X 10(5) cells)-1 2 h-1], respectively. ACTH-(1-24) stimulation on day 6 further increased the production of corticosteroids (3.5-fold) and B (2-fold), but had no effect on that of F. When cells were exposed to ACTH-(1-24) from the first day of culture on, there was a dramatic enhancement of F production which became, by day 6, 100 times higher (1746 +/- 149) than in the case of cells maintained in ACTH-free medium. Basal corticosteroid production by nontreated neonatal adrenal cells increased between day 1 and 6, and this was mainly due to B, the production of which increased from 10.1 +/- 0.2 to 447 +/- 35. ACTH-(1-24) stimulation of these cells on day 6 increased 2-fold the secretion of F and 1.5-fold that of B. ACTH-(1-24) treatment (2 h/day for 5 days) of neonatal cells increased 11-fold their production of F as compared with cells cultured in ACTH-free medium, and to a lesser extent that of B. In the second set of experiments, pregnenolone (8 X 10(-5) M) was added to the medium and its conversion to B and F was measured. On day zero the production of B and F by untreated fetal cells was 31 and 16 times higher than that of cells incubated without pregnenolone but stimulated by ACTH-(1-24); however, on day 6 the increase was only 2 and 5 times higher, respectively. On day 6 production of B and F by ACTH-treated cells was modestly increased by the addition of pregnenolone. The capacity of freshly isolated neonatal adrenal cells (day zero) to convert pregnenolone to B and F was 10- and 150-fold higher, respectively, than that of cells from fetuses.(ABSTRACT TRUNCATED AT 400 WORDS)

Stimulation of ribonucleic acid and deoxyribonucleic acid synthesis in spermatogenic cells by their coculture with Sertoli cells.

Germ cells were isolated from 30-day-old rat testes and purified by a Percoll gradient. Germ cells were cultured for 24 h to eliminate contaminant cells by utilizing the property of many nongerm cells of attaching to plastic surfaces. Germ cells were subsequently seeded on top of 7-day-old Sertoli cell monolayers. RNA and DNA synthetic activities were estimated by the rate of incorporation of [3H]uridine and [3H] thymidine into trichloroacetic acid-precipitable material. Germ cells increased RNA synthesis from 54,053 +/- 22,824 to 168,019 +/- 57,137 dpm/2 h X 10(6) cells (mean +/- SD) between 4 and 24 h of coculture, respectively (P less than 0.01), while they decreased this activity from 32,150 +/- 6,800 to 6,014 +/- 5,243 dpm when they were cultured alone for the same periods. Coculture of germ cells with either a cell derived from the adult bovine aortic endothelial cells (ABAE), or rat fibroblasts in primary culture prevented the fall in RNA synthesis but did not stimulate it. Addition of high concentrations of lactate to the culture medium did not have any affect in germ cells cultured alone but produced a slight stimulation in germ cells cocultured with ABAE cells, which was much smaller than the effect observed during coculture with Sertoli cells. Germ cells in coculture with Sertoli cells also increased their DNA synthesis from 2,186 +/- 765 at 4 h to 9,679 +/- 4,057 dpm [3H]thymidine/2 h X 10(6) cells at 24 h (P less than 0.05). When Sertoli cells were treated with FSH (1 microgram/ml), the synthesis of both RNA and DNA of germ cells cocultured with these cells was significantly higher than for germ cells cocultured with nontreated Sertoli cells. The system of coculture of Sertoli cells and germ cells consisted of the reassociation of the two previously isolated cells in a coculture, followed by their separation which permitted the effect of the coculture on the individual cell type to be assessed. By using this technique is was possible to obtain evidence suggesting that a chemical messenger other than lactate might be involved in the stimulatory effect of Sertoli cells on germ cells and that FSH increased this putative chemical messenger.

Regulation of guanine nucleotide binding regulatory proteins in cultured adrenal cells by adrenocorticotropin and angiotensin-II.

In addition to their steroidogenic effect on cultured bovine adrenal fasciculata cells ACTH and angiotensin-II (A-II) have a long term effect on the ability of these cells to respond to subsequent hormonal stimulation. The present work explores the effects of a 72-h pretreatment of adrenal cells with both hormones on the first steps of the mechanism of action of ACTH and A-II and on the amounts of the alpha-subunits of guanine nucleotide binding proteins Gs and Gi. ACTH but not A-II increased acute ACTH or cholera toxin-induced cAMP production. Moreover, ACTH but not A-II enhanced the amount of alpha S protein evaluated by cholera toxin ADP ribosylation, whereas both hormones elevated immunoblotted alpha S. Both hormones increased A-II induced phosphoinositide breakdown and Ca2+ uptake without modification of the A-II potentiating effect on ACTH-induced cAMP production. Treatment of cells with pertussis toxin (PT, 0.5 micrograms/ml) for the last 24 h reduced by 27% the A-II induced phosphoinositide breakdown in A-II pretreated cells but had no significant effect in ACTH-pretreated cells. No effect of PT was observed on A-II induced Ca2+ uptake or on its potentiating action on ACTH-induced cAMP production in ACTH as well as A-II-pretreated cells. Moreover, both hormones increased Gi proteins (40-41 kDa) evaluated by PT ADP ribosylation. Immunoblot analysis revealed that ACTH preferentially enhanced alpha i3, whereas the stimulatory effect of A-II was more marked on alpha i1 and alpha i2. These results indicate that in bovine adrenal fasciculata cells, peptide hormones settle target cell responsiveness not only by regulating the membrane-bound receptors, but also by modulating the level of G proteins coupling these receptors to the intracellular signals.