Abstract:
:Previous studies from this laboratory have demonstrated the presence of two populations of rat Leydig cells (I and II), which differ in their capacity for hCG- or cAMP-stimulated testosterone production. In the present study, we examined the metabolism of 25-hydroxycholesterol in primary cultures of both populations of Leydig cells. 25-Hydroxycholesterol bypasses the cAMP-dependent transport mechanism to the mitochondrial cytochrome P-450 side-chain cleavage enzyme (P-450scc) required by cholesterol and thus provides an index of the relative activity of P-450scc. Incubation of Leydig cells with increasing concentrations of 25-hydroxycholesterol resulted in a concentration-dependent increase in the amount of testosterone produced, with maximal amounts in both populations being reached at 25-hydroxycholesterol concentrations of 5 microM or greater. Population II produced more than twice as much testosterone as population I Leydig cells, whether incubated with 25-hydroxycholesterol or with 8-bromo-cAMP. Each population of Leydig cells produced 2.5-fold greater amounts of testosterone when incubated with 25-hydroxycholesterol than when incubated with 8-bromo-cAMP. In both populations of Leydig cells, cAMP-stimulated testosterone production was not different in cells cultured for 24 h from that in freshly isolated Leydig cells. These data suggest that cholesterol transport to P-450scc limits maximal testosterone production, and that the difference in hCG- or cAMP-stimulated testosterone production between the two populations of Leydig cells is primarily due to differences in P-450scc activity between the two populations and is not a result of population I consisting mostly of damaged Leydig cells.
journal_name
Endocrinologyjournal_title
Endocrinologyauthors
Georgiou M,Payne AHdoi
10.1210/endo-117-3-1184subject
Has Abstractpub_date
1985-09-01 00:00:00pages
1184-8issue
3eissn
0013-7227issn
1945-7170journal_volume
117pub_type
杂志文章相关文献
ENDOCRINOLOGY文献大全abstract::Insulin resistance and type 2 diabetes mellitus are associated with impaired postprandial secretion of glucagon-like peptide-1 (GLP-1), a potent insulinotropic hormone. The direct effects of insulin and insulin resistance on the L cell are unknown. We therefore hypothesized that the L cell is responsive to insulin and...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2008-0726
更新日期:2009-02-01 00:00:00
abstract::Notch signaling is an evolutionarily conserved pathway, which regulates cell proliferation, differentiation, and apoptosis. It has been reported that the members of Notch signaling are expressed in mammalian ovaries, but the exact functions of this pathway in follicle development is still unclear. In this study, prima...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2010-1182
更新日期:2011-06-01 00:00:00
abstract::Epidemiological evidence indicates that phytoestrogens inhibit cancer formation and growth, reduce cholesterol levels, and show benefits in treating osteoporosis. At least some of these activities are mediated through the interaction of phytoestrogens with estrogen receptors alpha and beta (ERalpha and ERbeta). Resver...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.141.10.7721
更新日期:2000-10-01 00:00:00
abstract::Estradiol-17beta (E2) is suspected to exert a role in the regulation of testicular activity. Using a nonmammalian vertebrate model (the frog, Rana esculenta), we have investigated whether c-fos activity is detectable in the testis during the annual sexual cycle and whether E2 exerts a regulatory role on spermatogenesi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.140.7.6790
更新日期:1999-07-01 00:00:00
abstract::Carbonyl cyanide trifluoromethoxyphenylhydrazone (FCCP), a protonophore, and methylamine, a weak base, agents that dissipate hydrogen gradients across cellular membranes, were used to probe the coupling of hydrogen gradients to the processing and secretion of the glycoprotein hormone hCG by human choriocarcinoma cells...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-119-1-416
更新日期:1986-07-01 00:00:00
abstract::Brown adipose tissue (BAT) thermogenesis is activated by the sympathetic nervous system. BAT responses to norepinephrine are blunted in hypothyroidism and are rapidly restored by thyroid hormone. We examined in rats the effects of thyroid hormone on BAT beta 1- and beta 2-adrenergic receptors (AR) expression and capac...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.136.8.7628360
更新日期:1995-08-01 00:00:00
abstract::In bone, early events in inflammation involve the production and release of primary proinflammatory cytokines, such as interleukin-1 beta. By activation of target cells, these cytokines are thought to induce a second wave of cytokines, including monocyte chemoattractant protein-1 (MCP-1). MCP-1 is a cytokine that stim...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.136.6.7750500
更新日期:1995-06-01 00:00:00
abstract::Thyroid hormones play a major role in body homeostasis, regulating energy expenditure and cardiovascular function. Given that obese people or athletes might consider rapid weight loss as beneficial, voluntary intoxication with T4 preparations is a growing cause for thyrotoxicosis. However, the long-lasting effects of ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2016-1095
更新日期:2016-07-01 00:00:00
abstract::Interferon-tau (IFNtau) is the embryonic signal responsible for pregnancy recognition in ruminants. The primary action of IFNtau is believed to be mediated through inhibition of prostaglandin F(2alpha) (PGF(2alpha)) released from the endometrial epithelial cells in response to oxytocin (OT). Our working hypothesis was...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2008-0704
更新日期:2009-02-01 00:00:00
abstract::T4-binding globulin (TBG), the principal carrier of thyroid hormone in serum, is a glycoprotein containing 20% carbohydrate. The importance of the carbohydrate moiety has been previously studied by enzymatic deglycosylation, which showed that deglycosylated TBG retains its original immunological an T4-binding properti...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-118-4-1614
更新日期:1986-04-01 00:00:00
abstract::P19 EPI-7, a differentiated murine embryonal carcinoma cell line with an epithelioid morphology, does not require external growth factors for proliferation under clonal and subconfluent conditions. At saturation density, however, cells become quiescent in the G1/G0 phase of the cell cycle from which they can be restim...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-124-4-2029
更新日期:1989-04-01 00:00:00
abstract::The central characteristic of uterine fibroids is excessive deposition of extracellular matrix (ECM), which contributes to fibroid growth and bulk-type symptoms. Despite this, very little is known about patterns of ECM protein expression in fibroids and whether these are influenced by the most common genetic anomalies...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2017-03018
更新日期:2018-02-01 00:00:00
abstract::The effects of insulin and glucose, alone and combined, on diacylglycerol (DAG), protein kinase-C (PKC), and glucose transport were compared in rat adipocytes and solei incubated in medium containing 0-20 mM glucose. In both tissues insulin rapidly stimulated [3H]DAG production from [3H]glycerol; extracellular glucose...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-128-6-2937
更新日期:1991-06-01 00:00:00
abstract::Chronic exposure to stressors impairs the function of multiple organ systems and has been implicated in increased disease risk. In the rodent, the chronic variable stress (CVS) paradigm has successfully modeled several stress-related illnesses. Despite striking disparities between men and women in the prevalence and e...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2018-00217
更新日期:2018-07-01 00:00:00
abstract::Type 2 deiodinase (D2), which is highly expressed in brown adipose tissue (BAT), is an enzyme that amplifies thyroid hormone signaling in individual cells. Mice with inactivation of the D2 pathway (D2KO) exhibit dramatically impaired thermogenesis in BAT, leading to hypothermia during cold exposure and a greater susce...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2010-0511
更新日期:2010-09-01 00:00:00
abstract::Kisspeptin neurons play an essential role in the regulation of fertility through direct regulation of the GnRH neurons. However, the relative contributions of the two functionally distinct kisspeptin neuron subpopulations to this critical regulation are not fully understood. Here we analyzed the specific projection pa...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2015-1131
更新日期:2015-07-01 00:00:00
abstract::The maternal plasma concentrations of GH and PRL increase dramatically upon the initiation of lactation in the rat. In light of the fact that these two hormones have evolved from one common precursor, we sought to determine if the neuroendocrine mechanisms regulating their concomitant increase during lactation are com...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-124-1-464
更新日期:1989-01-01 00:00:00
abstract::Female Wistar-Furth rats were implanted sc with GH3 rat pituitary tumor cells. Tumors were palpable by 4 weeks, and animals were killed periodically from 5-9 weeks. Tumor-bearing rats (n = 10) were heavier than their respective controls, reaching a weight of 372 +/- 3 by 9 weeks vs. 195 +/- 5 g in controls (mean +/- S...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-118-3-915
更新日期:1986-03-01 00:00:00
abstract::The gonadal steroids have long been known to modulate thyroid function. Most studies suggest that the gonadal steroids act indirectly through the hypothalamic-pituitary axis to modulate thyroid function. The following studies were conducted to determine whether there are receptors for androgens in the thyroid itself. ...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-115-6-2154
更新日期:1984-12-01 00:00:00
abstract::Potassium deficiency produced by feeding mice a low potassium diet caused a marked decrease in plasma and testicular testosterone concentrations and a concomitant fall in the weight of seminal vesicles and in renal ornithine decarboxylase activity. All of these parameters were rapidly restored when potassium supply wa...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.137.9.8756540
更新日期:1996-09-01 00:00:00
abstract::Enlargement of the chimeric ventral prostate gland (VP) was induced by directly implanting either fetal urogenital sinus mesenchyme (UGM) or intact fetal urogenital sinus (UGS) into the VP of intact adult rats. The macromolecular content in the chimeric prostate increased from 40-100% (UGM implants) to 200-300% (UGS i...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-118-6-2437
更新日期:1986-06-01 00:00:00
abstract::Oscillations in intracellular calcium levels have been described in GnRH-1 neurons in both prenatal and adult cells. However, differences have been reported in the mechanisms underlying these [Ca(2+)](i) oscillations, dependent on the model used. The goal of this study was to address whether these changes depend on th...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2010-0118
更新日期:2010-08-01 00:00:00
abstract::Androgenic glands (AGs) of the freshwater prawn Macrobrachium rosenbergii were subjected to endocrine manipulation, causing them to hypertrophy. Transcripts from these glands were used in the construction of an AG cDNA subtractive library. Screening of the library revealed an AG-specific gene, termed the M. rosenbergi...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2008-0906
更新日期:2009-03-01 00:00:00
abstract::The quantities of estrone and estradiol were determined by radioimmunoassay in maternal and fetal plasma of the rhesus monkey from day 59 to 163 of gestation. A two way analysis of variance of data classified according to fetal sex and 3 pooled gestational ages for each hormone and for mother or fetus (4 analyses) rev...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-97-2-425
更新日期:1975-08-01 00:00:00
abstract::We characterized four antipeptide polyclonal antibodies (abs) able to specifically recognize each thyroid hormone receptor (TR) isoform. The abs immunoprecipitated both the in vitro synthesized receptor and the receptor expressed in E. coli and their specificity was confirmed by competition studies and immunohistochem...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.131.5.1425440
更新日期:1992-11-01 00:00:00
abstract::In the present study the effects of stimulus deprivation on vasoactive intestinal peptide (VIP)- and alpha 1-adrenergically mediated amplification of VIP-stimulated cAMP and cGMP accumulation were examined. Dispersed pinealocytes were prepared from either Sprague-Dawley rats maintained for 2 weeks in a normal lighting...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-128-2-850
更新日期:1991-02-01 00:00:00
abstract::Androgen regulation of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) activities and accumulation of the mRNAs encoding these two enzymes in rodent kidney and accessory sex organs were studied. The ODC mRNA concentration and enzyme activity were increased by androgens in kidney, prosta...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.130.3.1537280
更新日期:1992-03-01 00:00:00
abstract::We investigated, in five cell strains per experiment, whether several cytokines known or believed to have effects on bone resorption were produced by nearly homogeneous strains of cultured normal human osteoblast-like (hOB) cells that display virtually the complete phenotype of the mature osteoblast. In unstimulated h...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo.130.5.1572280
更新日期:1992-05-01 00:00:00
abstract::Androgen-sensitive prostate cancer cells turn androgen resistant through complex mechanisms that involve dysregulation of apoptosis. We investigated the role of antiapoptotic Bcl-xL in the progression of prostate cancer as well as the interactions of Bcl-xL with proapoptotic Bax and Bak in androgen-dependent and -inde...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/en.2006-0502
更新日期:2006-10-01 00:00:00
abstract::Rat uterine and anterior pituitary microsomes each contain a population of specific estrogen-binding sites. Saturation binding of estradiol is demonstrable, with an affinity similar to that of the cytosol estrogen receptor (Ka = 1-2 X 10(10) M-1). Dissociation rate kinetic determinations, however, revealed that estrog...
journal_title:Endocrinology
pub_type: 杂志文章
doi:10.1210/endo-117-4-1341
更新日期:1985-10-01 00:00:00