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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to clarify the relationships between perivascular cells, capillaries and fat cells, with a special reference to the origin of fat cells, we have made a light and electron microscopical study on the developing epididymal adipose tissue of newborn to 5-week-old rats, and also on the differentiating, transplanted epididymal preadipose tissue from 6-day-old rats. Development of epididymal preadipose tissue progressed rapidly 6 or 7 days after birth. The preadipose tissue on the 5th day after transplantation consisted of differentiated areas with many mature fat cells, and of undifferentiated areas in which these cells were scanty. In the differentiated areas of developing epididymal preadipose tissue, both in situ and transplanted, many fat cells seemed to develop in the area immediately adjacent to growing capillaries, but cells intermediate between perivascular cells and preadipocytes were seldom observed. However, in undifferentiated areas of transplanted tissue, we found ultrastructural evidence that immature pericytes of capillaries can differentiate into preadipocytes.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 Oct
PMID:Electron microscopical studies on the genesis of white adipocytes: differentiation of immature pericytes into adipocytes in transplanted preadipose tissue. 4 11

The partial purification and characterization of specific rat epididymal proteins (SEP) is reported. Starting from the cytosol fraction obtained from epididymal homogenates, protein C was purified 15-fold and proteins D--E were purified 19-fold. The molecular weight, determined by molecular sieving, of protein C was 22,400 while that of D--E was 37,000. These proteins stained as glycoproteins with periodic acid--Schiff reagent. The isoelectric point of protein D was 5.13 while that of protein E was 4.95. Protein C separated into 3 bands during isoelectric focussing. The major component focussed at 5.56 and the two minor components at pH 5.38 And 5.79. Using a specific antiserum we could confirm the organ specificity of SEP and their androgen-dependence.
Mol Cell Endocrinol 1979 Jan
PMID:Isolation and characterization of specific rat epididymal proteins. 10 28

Testicular androgen-binding proteins (ABP) in rabbit testis, caput epididymis and efferent duct fluid (EDF) were compared to a similar androgen-binding protein TeBg) in rabbit serum. The affinity of these proteins for 5alpha-dihydrotesterone (DHT) at 0 degrees C (KaABP = 1.6 X 10(9) M-1 and KaTeBG = 1.9 X 10(9) M-1) and their steroid specificities were similar (DHT greater than androstanediol greater than progesterone and androstenedione). ABP and TeBG had also almost identical Stokes radii (42.8 +/- 1.2 and 43.9 +- 0.8 A, respectively), sedimentation coefficients (4.7 +/- 0.2 S and 4.4 +/- 0.2 S, respectively) and electrophoretic mobility (Rf = 0.4 in 6 1/2% polyacrylamide gels). Calculation of molecular weights from Stokes radii and sedimentation rates indicated a molecular weight of 74,000 (69,000-78,000) for TeBG and 76,000 (71,000-82,000) for ABP. The corresponding frictional ratios were 1.61 for TeBG and 1.55 for ABP assuming a partial specific volume (v) of 0.70 cm3/g. Polyacrylamide gel electrophoresis (PAGE) at different gel concentrations gave a mean molecular radius of 2.74 nm, also indicating a molecular weight of about 75,000 (v = 0.70 cm3/g. ABP and TeBG could not be separated by PAGE; however, partial separation of ABP and TeBG was achieved by isoelectric focusing and ion-exchange chromatography on DEAE-cellulose. TeBG focused at pH 5.4, whereas ABP formed a distinct peak of bound radioactivity at pH 4.7. Also by ionexchange chromatography, ABP in both testis and epididymal supernatants was shown to have an apparently higher surface charge than TeBG in rabbit serum. The concentration of ABP in efferent duct fluid (2 X 10(-7) M = 60 pmol/mg protien) was much higher than TeBG in male rabbit serum (5.2 X 10(-8) M = 0.7 pmol/mg protein). These findings ruled against the possibility that ABP in the testis and epididymis could have been derived directly from serum. It is concluded that ABP and TeBG are very similar if not identical proteins both serving as transport and carrier proteins in their respective compartments.
Mol Cell Endocrinol 1975 Jul
PMID:Testicular androgen-binding protein (ABP): comparison of ABP in rabbit testis and epididymis with a similar androgen-binding protein (TeBG) in rabbit serum. 16 2

After i.m. injection of [3H]butyrobetaine into rats, the accumulation of carnitine into the epididymis, prostate gland, seminal vesicles, testis and heart was studied. The concentration of radiolabeled carnitine into the cauda epididymis increased linearly with time up to 72 h after the injection of the precursor, while its level in the prostate and seminal vesicles decreased rapidly. Very low levels of carnitine were found in the testis. Castration reduced the carnitine accumulation by cauda epididymis to 6% of the control levels while treatment of castrated animals with testosterone propionate (500 mug/day) partly restored the carnitine uptake. Similar treatment with 17beta-oestradiol valerate or 17alpha-hydroxyprogesterone had no effect. Surprisingly, cyproterone acetate (5 mg/day) also significantly stimulated carnitine accumulation by the epididymis to a level above that of the castrated controls. Simultaneous injection of both cyproterone acetate and testosterone propionate to castrated animals caused an additive effect of these steroids. This indicated that cyproterone acetate in this system is working as a weak androgen. Treatment of rats with 17beta-oestradiol valerate also reduced carnitine accumulation by the cauda epididymis. This is due to suppression of pituiatry gonadotrophin secretion, since concommitant treatment with testosterone propionate (500 mug/day) caused a normalization of the carnitine uptake. Treatment of intact rats with cyproterone acetate significantly reduced the epididymal weight, but not the carnitine accumulation. 17alpha-Hydroxyprogesterone treatment had no effect either on the epididymal weight or the accumulation of the carnitine. Unilateral orchiectomy reduced the carnitine accumulation by the cauda epididymis to about 40% of that occurring in the non-operated control side. This indicates that the luminal contact between the testis and epididymis or the luminal content of the epididymis itself is of importance for the androgen-dependent metabolic process occurring in the cauda epididymis. Castration or hormone treatment did not change the conversion of butyrobetaine to carnitine, or the carnitine uptake by heart. Carnitine uptake by the testis after [3H]butyrobetaine injection was rather low and this would exclude the possibility of synthesis of carnitine in the testis as a source of epididymal carnitine. Carnitine only accumulated in the cauda epididymis in vivo 4 to 96 h after injection of [3H]butyrobetaine. The presence of radioactively labeled butyrobetaine or methylcholine was not detected.
Mol Cell Endocrinol 1975 Aug
PMID:Androgen-dependent accumulation of carnitine by rat epididymis after injection of [3H]butyrobetaine in vivo. 17 Jan 50

The cytoplasmic recptor (CR) in rat epididymal 105,000 g supernatant was separated from the androgen-binding protein (ABP) by gel electrophoresis following labeling with [1,2,6,7-3H]-testosterone in vivo. ABP disappeared from epididymal supernatants after castration of hypophysectomy, while CR remained unchanged. CR was evenly distributed between caput and cauda, while much more ABP was present in caput. Properties of CR in epididymis and prostate were similar and distinctly different from ABP. Binding to CR was destroyed by charcoal treatment (1 mg/mg protein) of supernatant for 0 degrees C for 6 h, heating at 50 degrees C for 30 min, or exposure to the sulfhydryl blocking reagent, p-chloromercuriphenylsulfonate (1mM) at 25 degrees C for 30 min, while binding to ABP was unaffected. The isoelectric pH of CR (5.8) was higher than that of ABP (4.6). Dissociation of radioactive 5alpha-dihydrotestosterone (DHT) from CR and nuclear receptors was extremely slow (half-time at 0 degrees C is greater than 2 days), while dissociation from ABP was rapid (half-time at 0 degrees C is similar to 6 min). Cyproterone acetate (250 mg/100 g body weight) inhibited binding to CR both in epididymis and ventral prostate but did not affect binding to ABP. Nuclear uptake was inhibited by cyproterone to the same extent as binding to CR, indicating that nuclear uptake and binding are dependent on CR and independent of ABP. The time-course of uptake and binding in epididymal supernatant and nuclear fractions was essentially the same 1 day after bilateral castration when both CR and ABP were present or 8 days after castration when CR alone was present. It is concluded that the cytoplasmic receptor for androgen in rat epididymis has properties very similar to the androgen receptor in ventral prostate but different from ABP.
Mol Cell Endocrinol 1975 Aug
PMID:Androgen-binding proteins in rat epididymis: properties of a cytoplasmic receptor for androgen similar to the androgen receptor in ventral prostate and different from androgen-binding protein (ABP). 17 Jan 53

We previously demonstrated that the caput epididymis of intact sexually mature rabbits contains a specific high-affinity binding protein for 5alpha-dihydrotestosterone (5alphaDHT). The other anatomical segments (corpus and cauda) of the epididymes of these animals had no detectable 5alphaDHT-binding activity. We have further shown that this binding was due to an androgen-binding protein of testicular origin. In the present study we have investigated 5alphaDHT binding to epididymal cytosol from sexually immature rabbits (20-104 days old). Using sucrose gradient ultracentrifugation, we have detected a unique pattern of binding. The pattern correlated well with testicular and epididymal maturation, but there was little correlation with chronological age or body weight. In the most immature animals (Group I) the seminiferous tubules appeared as solid cords and the epithelium of the ductus epididymis detectable 5alphaDHT-binding activity. In the second group (Group II), there was 5alphaDHT-binding to all three segments. The seminiferous tubules of these rabbits exhibited spermatogenic activity and lumen formation. The height of the epididymal epithelium had increased uniformly throughout the duct. The third group (Group III) had 5alphaDHT-binding only in caput cytosol. Spermatogenesis had progressed to the formation of elongated spermatids in the most immature animals of this group to the release of spermatozoa in the most mature ones. The caput epithelium of this last group of rabbits was fully differentiated. Unilateral orchidectomy of Group II rabbits resulted in a decrease in [3H]5alphaDHT-binding activity on the operated side as compared to the contralateral non-operated control side, suggesting the testicular origin of the binding protein. The failure of cyproterone or cyproterone acetate to inhibit [3H]5alphaDHT-binding to the protein, the lack of effect of N-ethylmaleimide on binding, and the rapid dissociation rate of the [3H]5alphaDHT-binding protein complex suggested that the binding moiety was testicular androgen-binding protein (ABP).
Mol Cell Endocrinol 1975 Sep
PMID:Changes in 5alpha- dihydrotestosterone binding to epididymal cytosol during sexual maturation in rabbits: correlation with morphological changes in the testis and epididymis. 17 Nov 84

The in vitro effects of insulin on different phosphodiesterase activities present in rat epididymal fat cells from normal and hypothyroid rats have been studied. Evidence is presented that insulin increases the maximum velocity of a particulate, low Km, cyclic adenosine-3', 5'-monophosphate (cyclic AMP) phosphodiesterase in both types of cells, this effect being more clearly evident with the fat cells from hypothyroid animals; combination of insulin and thyroidectomy resulted in a 400% stimulation with 10-10 - 10-9 M insulin. A clear and significant effect was apparent at 10-11 M insulin. However, the dose-response curve was biphasic, since stimulation by insulin was suppressed for doses of hormone higher 10-8 - 10-7 M. Moreover, insulin effects were very fast, since clear stimulation was observed after only 2 min of incubation; the maximal increase was obtained after 10 min. Insulin did not significantly affect the soluble cyclic AMP phosphodiesterase activity in normal cells, thus confirming results obtained by others. However, the soluble cyclic AMP phosphodiesterase activity was clearly stimulated by insulin when the fat cells were prepared from hypothyroid rats. Maximal stimulation was obtained with 10-9 M insulin; the response was again very fast. Soluble cyclic GMP phosphodiesterase activity was also increased additively by hypothyroidism and insulin, maximal stimulation being obtained with 10-9 M insulin. With this dose of insulin the additive effects of thyroidectomy and insulin produced a 5-fold stimulation. The effect of insulin on the soluble cyclic GMP phosphodiesterase was very fast (2-5 min). With both soluble cyclic nucleotide phosphodiesterase activities, insulin increased the maximal velocity but not apparent Km of the enzyme. Thus, hypothyroidism and insulin produced additive effects suggesting a different mechanism of action of these two hormonal situations on the degradation of the intracellular pools of cyclic AMP and cyclic GMP.
Mol Cell Endocrinol
PMID:Cyclic nucleotide phosphodiesterases, insulin and thyroid hormones. 18 75

In this work the kinetics of activation of the cyclic AMP-dependent protein kinase by several catecholamines and ACTH, have been studied in rat epididymal fat pads and isolated fat cells. The method of Soderling and co-workers which permits the measurement of the state of activation of the protein kinase after hormonal stimulation in adipose tissue, has been used. Kinetics experiments where norepinephrine was used showed that the results obtained with isolated cells conform to the models of Sutherland and Brostrom and co-workers. Wtih intact tissue, norepinephrine not only stimulates the protein kinase activity measured without exogenous cyclic AMP but also the total activity measured in the presence of cyclic AMP (5 X 10(-6) M); thus the effect of norepinephrine, obtained during incubation of the tissue, and that of cyclic AMP, added to the soluble fraction after incubation, were additive. This effect seems to be of the beta type because it is blocked completely by propranolol. A weak, additive but significant effect was also obtained with epinephrine and isoproterenol but not with ACTH. Neither cyclic GMP nor cyclic IMP seems implicated in this effect. It was shown that stroma vascular cells which are present in the fat pads are not involved. These results suggest that the effects of norepinephrine on the protein kinase of the fat pads cannot be completely explained by the model of Brostrom and colleagues.
Mol Cell Endocrinol 1976 Oct
PMID:Additive effects of norepinephrine and cyclic AMP on the activation of the protein kinase from adipose tissue. 18 9

After i.m. injection of [3H]butyrobetaine into intact and castrated rats, the specific activity of plasma carnitine remained nearly constant over 24--96 h and epididymal uptake of carnitine was constant per unit time up to 72 h. The uptake ratio of intact to castrated rats was high at 48, 72 and 96 h after injection. Administration of estradiol valerate over 20 days reduced carnitine uptake in epididymis. This reduction was dose-dependent when estrogen was administered i.m. at 0.33--10 microgram/day levels. A maximum reduction of 90% was obtained with the 10 microgram dose. A dose increase from 33 to 100 microgram/day caused no further reduction. Norspiroxenone (2--10 mg/day) and SK 7670 (1.5 and 7.5 mg/day) were less effective than estradiol valerate (10 microgram/day) in suppressing carnitine uptake in epididymis. Epididymal carnitine uptake in estradiol valerate treated rats (33 microgram/day for 20 days) increased in a time- and dose-dependent manner under testosterone propionate treatment (50, 250, 1250 microgram/day). Carnitine uptake increased to 80% of the nonsuppressed levels when testosterone propionate was adminsitered over a 6-day period at 1250 microgram/day. Dihydrotestosterone increased epididymal carnitine uptake to the same extent as testosterone propionate. delta4-androstene-3,17-dione and 5alpha-androstane-3alpha,17beta-diol (50 microgram/day) were less effective, stimulating uptake to only 15% and 40% respectively of the testosterone propionate (250 microgram/day) stimulated levels. Changes in epididymal carnitine uptake evoked by various experimental procedures were closely paralleled by weight changes in the ventral prostate. This response resemblance indicates a similarity between the androgen sensitivity of the prostate gland and that of the carnitine uptake system in epididymis. The dose-dependent effect of estrogen on the accumulation of epididymal carnitine, together with the marked responses induced in this system by manipulation of its androgen status, support a possible use for the system as an assay for androgen or antiandrogen potency in vivo.
Mol Cell Endocrinol
PMID:Accumulation of carnitine in rat epididymis after injection of [3H]butyrobetaine in vivo: quantitative aspects, and the effects of androgens and antiandrogens. 68 Mar 41

The effect of age at hypophysectomy on the response of the regressed rat testis to testosterone propionate (TP) and FSH with respect to androgen-binding protein (ABP) levels was studied in individual animals. All treatments were begun 30 days after surgery. Treatment of rats 35, 45, 55 and 75 days of age at surgery with TP (1 mg/260 g for 25 days) significantly increased the level of ABP in the testes of animals in all age groups except those hypophysectomized at 35 days of age. TP treatment did not significantly elevate epididymal levels of ABP above those found in untreated rats in any age group. In animals hypophysectomized at 100 days of age, acute treatment (3 days) with FSH (150 and 300 mug/day) significantly increases the ABP levels per testis and per epididymis. Similar treatment with 750 mug TP/day did not result in a statistically significant increase in testicular ABP. No synergism between the two hormones was noted under the conditions described. Significant restoration of testicular ABP levels per mg protein was achieved with 1 mg TP/day by 5 days of treatment. Treatment of hypophysectomized adult rats with FSH raised the epididymal/testicular ratio of ABP to about 40% of that found in intact rats while comparable treatment with TP (750 mug/day for 3 days or 1 mg/day for 10 days) only slightly affected the ratio. It is postulated that FSH may facilitate ABP transport to the epididymis in addition to affecting its production by the testis.
Mol Cell Endocrinol 1977 Jan
PMID:Effect of testosterone propionate on ABP levels in rats hypophysectomised at different ages using individual sampling. 83 63


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