Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The goal of this study was to discriminate between two hypotheses regarding how the circadian rhythm of pineal melatonin (MEL) production transmits photoperiodic information: (1) A circadian rhythm of sensitivity to MEL regulates the hormone's effect; (2) the duration of the MEL signal, rather than its circadian timing, is the critical parameter of the MEL rhythm. The experiment examined the response of pinealectomized (PINX) male Siberian hamsters to 10-hr (short-day-type) versus 6-hr (long-day-type) duration MEL infusions (10 ng/infusion) in cycles with period lengths (T) of 18, 24, 36, and 48 hr. After cannula implantation, animals were moved from LD 16:8 to LD 10:14 (lights-on from 0500 to 1500 hr, EST), where the timed infusions began. Additional T 24 cycles included as controls employed 18-hr MEL, 18-hr saline (SAL), and 10-hr SAL infusions: Body weight and food intake were measured weekly. After 6 weeks, animals were killed; blood samples were taken for radioimmunoassay (RIA) of serum follicle-stimulating hormone (FSH) and prolactin (PRL); and terminal body, epididymal white adipose tissue (EPIWAT), and paired testis weights were recorded. Six-hour MEL infusions failed to induce short-day-type effects, regardless of the period (T) of the infusion cycle. In contrast, compared to SAL and 6-hr MEL infusions, 10-hr MEL resulted in decreases in body, EPIWAT, and testis weights in T 24, but not in T 36 or T 48. In T 18, testis, body, and EPIWAT mass were decreased, but not to the same extent as in T 24. Similarly, daily 18-hr MEL infusions (T24) were less effective as a short-day stimulus than were 10-hr MEL infusions. The effectiveness of 10-hr, but not 6-hr, MEL infusions in T 18 and T 24 is consistent with the duration hypothesis and argues against the circadian hypothesis. Neither hypothesis could have predicted that all infusion cycles of T greater than or equal to 36 hr, regardless of the infusion durations, would fail to elicit short-day-type responses. This outcome suggests a need for relatively frequent (T less than 36 hr) MEL stimulation in addition to the requirement for adequate duration of each MEL infusion.
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PMID:Effect of melatonin infusion duration and frequency on gonad, lipid, and body mass in pinealectomized male Siberian hamsters. 251 5

Estrogen sulfotransferase (EST) catalyzes the sulfoconjugation and inactivation of the steroid hormone estrogen. It is known previously that EST is expressed abundantly in Leydig cells of the testis. We recently have shown that male mice with targeted EST gene disruption developed age related Leydig cell and seminiferous tubule abnormalities as a consequence of increased local estrogen stimulation. In the same study, we also found that epididymal sperm isolated from the mutant mice had significantly reduced motility, but whether this reflected impaired epididymal function or was secondary to the testicular lesions was not known. The purpose of the current study was to investigate if EST is normally present in the mouse epididymis and/or other parts of the male reproductive tract where, as in testis, it may play a role in regulating local estrogen homeostasis. We describe here that EST is expressed in the epithelium of corpus and cauda but not caput regions of the mouse epididymis. It is also expressed in the luminal epithelium and smooth muscle cells of the vas deferens but was present at very low levels, if at all, in the prostate or seminal vesicle/ coagulating gland. Hypophysectomy, castration, and epididymal ligation experiments, together with the use of an androgen receptor antagonist, established that EST expression in the epididymis and vas deferens is critically dependent on pituitary hormone(s) and androgen but not on other factors in the testicular fluid. Administration of exogenous estradiol to mice with surgically ligated epididymis resulted in a more pronounced reduction in sperm motility in EST mutant mice than in wild-type mice. We conclude that EST is discretely expressed and regulated in the male reproductive tract and plays a physiological role in maintaining the functional integrity of the epididymis by regulating luminal estrogen homeostasis.
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PMID:Estrogen sulfotransferase: discrete and androgen-dependent expression in the male reproductive tract and demonstration of an in vivo function in the mouse epididymis. 1213 May 80

Although primarily regarded as a sex steroid, estrogen plays an important role in many other physiological processes including adipose development and disposition. Estrogen sulfotransferase (EST) regulates estrogen activity by catalyzing the sulfoconjugation and inactivation of estrogens. In the present study, we report the gender-specific expression of EST in adipose tissues of the mouse and describe contrasting mechanisms of EST regulation in the fat and liver. EST is expressed in the white adipose tissues of the male but not female mouse. Within the various fat depots of male mice, it is most abundantly expressed in the epididymal fat pad, with variable levels in other white fats and no expression in the brown fat. Fractionation of epididymal fat cells showed EST to be predominantly associated with stromal vascular cells (preadipocyte). EST expression in male mouse adipose tissues is dependent on testosterone as castration ablated, and administration of exogenous testosterone restored, EST expression. Furthermore, testosterone treatment induced abnormal EST expression in the parametrial fat of female mice. EST induction by testosterone in female mice is tissue specific because testosterone treatment had no effect on liver EST expression. Conversely, the liver X receptor agonist TO-901317 induced EST expression in female mouse liver but not in their adipose tissues. Finally, we demonstrate that male EST knockout mice developed increased epididymal fat accumulation with enlarged adipocyte size. We conclude that EST is expressed in adipose tissues in a sexually dimorphic manner, is regulated by testosterone, and plays a physiological role in regulating adipose tissue accumulation in male mice.
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PMID:Gender-specific expression and mechanism of regulation of estrogen sulfotransferase in adipose tissues of the mouse. 1866 2

Estrogen is found in high concentrations in the excurrent duct, where it regulates the expression of genes involved in water reabsorption. Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes specific sulfonation with a high affinity for estrogens. Because sulfated estrogens do not bind to estrogen receptors, they are considered to be hormonally inactive. EST may thus determine where along the male tract estrogenic environment predominates. Sulfotransferase activity increases along the epididymis and may also play a role in sperm physiology during the epididymal transit. Using a bovine model, we investigated the distribution of EST along the excurrent duct and the possibility that sterols associated with spermatozoa can be substrates of this enzyme. Reverse transcription polymerase chain reactions showed that mRNA encoding EST was expressed in the testis and all along the epididymis. A highly specific antiserum was raised against the bovine recombinant EST and used in Western blots and immunohistologic studies. Western blots of tissue homogenates showed that EST was localized all along the excurrent duct with a higher signal in the caput and corpus epididymidis. EST was detectable in the intraluminal compartment only in the caput epididymidis, where it was associated with epididymosomes and spermatozoa. EST was undetectable in different fractions of fluids collected in the cauda segment. In immunohistologic studies, EST was restricted to the acrosomal region of the caput, but not the cauda epididymal spermatozoa, and detectable in the cytoplasm of the epithelium bordering the lumen all along the epididymis as well as in the rete testis and vas efferens. This enzyme was also associated with the nucleus in the caput and corpus as well as with the apical membrane of the corpus epididymal epithelium. When recombinant EST was incubated in vitro in the presence of caput and cauda spermatozoa, it was able to add sulfate to sperm membrane cholesterol. Our study shows that EST is present in both the intracellular and intraluminal compartments of the epididymis, suggesting that this enzyme plays different roles along the excurrent duct.
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PMID:Estrogen sulfotransferase is highly expressed along the bovine epididymis and is secreted into the intraluminal environment. 1923 12

The activities of steroid sulphatase (StS) and estrogen sulphotransferase (EST) were determined in the epididymis of 18 boars. The animals were divided into three groups (n=6) according to age (8, 12 and 16 months). The boars were anesthetized and castrated. The tissue samples of different epididymal parts (caput, corpus and cauda) were taken and homogenized. Activities of StS and EST were assessed using (3)H-estrone sulphate ((3)H-E1S) and free (3)H-oestrone ((3)H-E1) as substrates, respectively. The substrate conversion rates after 60 min of incubation were 51.25% for (3)H-E1S and 45.65% for (3)H-E1. The activities of both enzymes were significantly higher in the caput epididymis compared to the cauda epididymis (p<0.05). A significant age-dependent increase of StS and EST activities (p<0.05) was observed. These results suggest that the availability of estrogens in the boar epididymis may be locally controlled also by StS and EST. The age-dependent increase of StS and EST activities may be related to the process of "biochemical maturation" of the reproductive system during the postpubertal period.
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PMID:Activity of steroid sulphatase and estrogen sulphotransferase in the boar epididymis during the postpubertal period. 2322 10