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)

Testis growth is stimulated when short photoperiod-regressed Siberian hamsters are exposed to a lengthening photoperiod, an effect presumably mediated by the pineal gland through a decrease in the peak nocturnal duration of secretion of its hormone melatonin (MEL)(D. S. Carter and B. D. Goldman, Endocrinology 113: 1268-1273, 1983). We examined this stimulatory or "progonadal" effect of MEL in short photoperiod-regressed, adult male Siberian hamsters that were pinealectomized (PINX) and given timed daily subcutaneous 1) injections of MEL (1 or 10 micrograms/day) or saline or 2) infusions of MEL that were "long day-like" (4 h, 10 or 100 ng/day), "short day-like" (10 h, 10 ng/day), or control saline infusions (4 h/day). Photoregressed sham PINX hamsters were transferred to long days at this time. After 5 wk of treatment, 1-microgram MEL-injected hamsters and both groups of 4-h MEL-infused hamsters had stimulatory responses that mimicked those of the long-day-exposed, sham PINX group [i.e., increased testes, body, and epididymal white adipose tissue (EPIWAT) weights, total body fat, EPIWAT lipoprotein lipase activity, and serum prolactin and follicle-stimulating hormone levels]. These effects were not observed in 10-micrograms MEL- or saline-injected and 10-h MEL- or saline-infused hamsters. Thus the peak nocturnal duration of serum MEL is the critical parameter of the MEL secretion profile for stimulating a variety of photoperiodic responses when photoregressed hamsters are exposed to lengthening daylengths.
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PMID:Effects of melatonin on long-day responses in short-day housed adult Siberian hamsters. 314 82

Yorkshire boars were used to evaluate the influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions. At 10 wk of age, 5 hemicastrate (HC) and 5 intact (I) boars were assigned to either 8 or 16 hr of light daily until 6 mo of age. Body weights were recorded biweekly throughout the experiment. Venous cannulae were placed in all boars at 6 mo of age, and serum was collected at 30 min intervals from 0800 to 2000 hr. Gonadotropin releasing hormone (GnRH) was infused at 2000 hr (50 micrograms) and at 2030 hr (250 micrograms), and samples of serum were collected until 2400 hr. The following day, all boars were castrated, and the weights and sperm content of the testes and epididymides were determined. At castration, all pigs were given implants containing testosterone. Two weeks later, pigs were again canulated, and serum was obtained at 15 min intervals for 2 hr. Growth of boars was not significantly affected by duration of photoperiod or number of testes. Duration of photoperiod did not affect weight or sperm content of testes or epididymides. Hemi-castrated boars had greater testicular (P less than .01) and capita-corpora (C-C) epididymal weights (P less than .05) and more testicular and C-C sperm (P less than .01) per testis. Neither average concentrations of luteinizing hormone (LH) nor number and amplitude of pulses of LH were affected by photoperiod treatment. However, HC boars had greater average concentrations of LH (P less than .05) than I boars (.71 +/- .05 vs .52 +/- .05 ng/ml). Hemicastrated boars in 16 hr light daily had greater concentrations of FSH in serum (P less than .05) than 8I, 8HC, and 16I boars. Intact and HC boars had similar concentrations of prolactin (PRL) and testosterone. Similarly, concentrations of PRL and testosterone were not affected by duration of photoperiod. Secretion of LH and testosterone after treatment with GnRH was not significantly affected by duration of photoperiod. In general, HC boars released more LH in response to GnRH treatment than I boars. Concentrations of LH were greater (P less than .05) in HC than I boars at .5, 1, 2, and 3 hr after GnRH and tended (P less than .10) to be elevated at 1.5, 2.5, 3.5 and 4 hr after GnRH. The FSH response to GnRH was greater (P less than .05) for 16HC than 8I, 8HC, or 16I boars.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions of boars. 314 65

Long photoperiod-housed, adult Siberian hamsters were pinealectomized and given daily subcutaneous infusions of melatonin (MEL) to determine which characteristic of the MEL secretion profile is critical for short photoperiod-induced physiological responses. Long-duration MEL infusions (10 or 12 h) given for 5 wk elicited short-day-type responses [i.e., decreased body, testes, and epididymal white adipose tissue (EPIWAT) weights, EPIWAT lipoprotein lipase activity, carcass lipid content, and serum follicle-stimulating hormone and prolactin levels]. In contrast, short- or intermediate-duration (5 or 8 h) MEL infusions or saline infusions were without effect. Long-duration MEL infusions elicited short-day-type responses independently of both the time of day when MEL was administered and of the MEL dose if the latter was greater than or equal to 6.25 ng MEL/daily infusion. The continuity of the 10-h MEL infusions was important for triggering short-day-type responses; 10-h MEL infusions interrupted at their midpoint by 2 h of no infusion were ineffective even though dose and total duration were held constant. The body and lipid mass decreases were independent of the gonads, since castrated and gonad-intact hamsters responded similarly to the daily 10-h MEL infusions. Decreased body weight resulting from long-duration MEL infusions were never accompanied by decreased food intake. We conclude that the peak nocturnal duration of MEL is the critical parameter of the MEL secretion profile for triggering short-day-induced responses in adult Siberian hamsters.
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PMID:Peak duration of serum melatonin and short-day responses in adult Siberian hamsters. 318 92

Hyperprolactinemia, induced by pituitary isografts for 20 weeks in male mice and confirmed by radioimmunoassay using anti-mouse prolactin serum, did not impair spermatogenesis in the testis and maturing processes of spermatozoa in the epididymis. Incubation of freshly obtained epididymal spermatozoa for 90 min in culture media containing various levels of mouse prolactin did not yield any adverse effects on percentage motility rates of epididymal spermatozoa. When the level of mouse prolactin in the preincubation medium for epididymal spermatozoa was 100 ng/ml, the rate of fertilization by these preincubated spermatozoa in the subsequent in vitro fertilization experiment was significantly lowered compared with that observed in controls. However, when the level of prolactin in preincubation media was 10 ng/ml, no significant reduction in the rate of fertilization occurred. The present experiments seem to indicate the existence of some differences in the effects of prolactin on male germ cells until they reach the tail of the epididymis and on the processes of capacitation and/or fertilization by epididymal spermatozoa after they leave the epididymis.
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PMID:Influences of prolactin upon spermatogenesis and spermatozoa during in vitro fertilization in mice. 341 Nov 76

Reductions of prolactin secretion by bromocriptine treatment for 24 days reduced fat stores (abdominal and epididymal fat depots) in hamsters by 25-49% compared with control animals. However, body weights and food consumption were not affected. These results further substantiate an important role for prolactin in regulation of fat metabolism and indicate that bromocriptine might be used to decrease fat stores.
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PMID:Reduction of body fat stores by inhibition of prolactin secretion. 356 91

Corticosterone-induced changes in serum hormone profiles and the lipid composition of the caput and cauda epididymidis were studied. The analysis was conducted in both unwashed and washed (free from fluids and spermatozoa) epididymal tissues. Corticosterone treatment significantly depressed serum prolactin and testosterone but gonadotropins were unaltered. In the unwashed caput region, lipid analysis showed a significant decrease in total lipids, as well as in cholesterol, phospholipid, and the phosphatidyl inositol, phosphatidyl choline, and phosphatidyl ethanolamine fractions. However, in the unwashed cauda region, the total lipid and cholesterol content was not altered while total phospholipid and phospholipid fractions were significantly decreased. On the other hand, in the washed caput and cauda regions, corticosterone induced a significant increase in total lipid, glyceride, and the mono, di, and triglyceride fractions, leaving total phospholipid and its fractions unaltered. Following 20-day withdrawal of corticosterone treatment, all lipid classes returned to normal along with serum hormone profiles. Our findings imply that an excess of corticosterone influences epididymal lipids. These changes in the epididymal lipid pattern probably are reflected in fertility disorders in patients with glucocorticoid excess.
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PMID:Effect of corticosterone on rat epididymal lipids. 358 9

The immunoreactive prolactin in human seminal plasma originates predominantly from two sources, the seminal vesicles and the testicular-epididymal axis. The following evidence supported a testicular-epididymal origin: Vasectomy reduced the content of prolactin in the ejaculates by 50%; the concentration of seminal prolactin was highly correlated (r = 0.54, p less than 0.003) with the concentration of sperm in a normal population of young and middle-aged men; and prolactin concentrations in the split ejaculates of normospermic men revealed a profile that corresponded to the sperm distribution pattern. Evidence supporting an additional contribution from the seminal vesicles included the following. The split ejaculate of an azoospermic individual coincided more with the distribution of the vesicular parameter fructose; vasectomy did not cause the disappearance of prolactin from the ejaculate; and split-ejaculate analyses weakened the possibility of a major prostatic source.
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PMID:Testicular and glandular contributions to the prolactin pool in human semen. 383 69

The pattern of androgen dependent enzyme activities of epididymis was studied after the administration of prolactin and bromocriptine in albino rats. Prolactin activated the glycogenolysis and hexose mono and diphosphate pathways, which would be essential for sperm maturation. But bromocriptine inhibited these activities of epididymis. Hence role of bromocriptine in decreasing epididymal function has been suggested.
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PMID:Effect of prolactin and bromocriptine administration on epididymal function--a biochemical study in rats. 384 78

Bovine growth hormone (somatotropin) was extracted from anterior pituitaries and fractionated into four protein peaks (A-D) by chromatography on DEAE-Sephacel. Analysis by high-pressure liquid chromatography and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis indicated that the homogeneity of the material increased from fraction A through to D. The properties of the fractions were examined in the following manner: immunological activity (radioimmunoassays for ruminant growth hormone and prolactin); growth-promoting activity (rat tibia test); lipolytic activity (release of glycerol from rat epididymal fat in the presence of dexamethasone); diabetogenic activity (rate of glucose transport in epididymal fat of hypophysectomized rats and intravenous insulin-tolerance tests in goats). None of the fractions contained immunoreactive prolactin and all were equally lipolytic. Although fraction A contained a small quantity of immunoreactive growth hormone it had no growth-promoting or diabetogenic activities. Both fractions B and C were diabetogenic and contained high concentrations of immunoreactive growth hormone, consistent with their growth-promoting activity. Although the growth-promoting activity of fraction D was higher than that of the other three fractions, it was not diabetogenic and was only weakly immunoreactive. These results for bovine growth hormone support the contention that growth hormone, as commonly extracted, is a mixture of different molecular forms and that these different metabolic properties of the hormone might be explained in terms of this heterogeneity.
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PMID:The heterogeneity of bovine growth hormone. Extraction from the pituitary of components with different biological and immunological properties. 637 Feb 42

The effect of adrenalectomy and corticosterone replacement on epididymal enzymes involved in obligatory steps of glycolysis and pentose phosphate pathway were studied along with serum hormonal profiles. Adrenalectomy was found to elevate serum prolactin while the gonadotropins and testosterone were unaltered. In caput epididymal tissue enzymes of the pentose phosphate pathway. Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities were increased after adrenalectomy. However, in corpus epididymal tissue the key enzymes viz. hexokinase, 6-phosphofructokinase and pyruvatekinase of the glycolytic pathway were elevated leaving the pentose phosphate pathway unaffected. Adrenalectomy was also found to favour glycolysis of the epididymal spermatozoa. The possible direct effect of prolactin is discussed to explain the enzymatic changes in epididymis. Corticosterone replacement was found to maintain the enzyme activities along with serum prolactin and corticosterone at control levels. In conclusion, it is suggested that the adrenalectomy induced changes in enzyme activities could be due to the direct effect of prolactin.
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PMID:Effect of adrenalectomy and corticosterone replacement on epididymal carbohydrate metabolism--studies on mature male rats. 640 94


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