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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prolactin concentration in human seminal plasma and in human epididymal cauda fluid was assessed by radioimmunoassay. The prolactin concentration in cauda plasma was found to be similar to that found in male blood serum (5.5 to 9.1 ng/ml) and significantly lower than the concentration of the hormone found in seminal plasma obtained either from euspermic (48 +/- 12 ng/ml) or from vasectomized volunteers (50 +/- 10.2 ng/ml) (P less than 0.001). Calcium binding and/or transport in ejaculated spermatozoa were found to be little (0.29 +/- 0.08 nmoles/10(8) cells) and dependent on a quickly saturable process. The addition of 200 ng of human prolactin/ml induced a 60% increase in this parameter, while 50 ng of prolactin/ml were ineffective. Epididymal human spermatozoa differ from ejaculated sperm cells in showing greater, time-dependent, calcium binding and/or transport under basal conditions (2.00 +/- 0.35 nmoles/10(8) cells/hour), and in being more susceptible to the stimulating action of prolactin (4.4 +/- 0.68 nmoles/10(8) cells/hour in the presence of 50 ng of prolactin/ml).
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PMID:Effect of prolactin on the calcium binding and/or transport of ejaculated and epididymal human spermatozoa. 22 Dec 77

The effects of unilateral orchidectomy on the adult rat epidiymal testosterone metabolizing enzymes, delta 4-5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase, are investigated. Five weeks following unilateral orchidectomy, it is found that the activity of 3 alpha-hydroxysteroid dehydrogenase per organ is not altered, whereas delta 4-5 alpha-reductase activity decreased by more than 80% on the side of the orchidectomy. Neither accessory sex tissue weights, ventral prostate and seminal vesicles, nor the concentration of circulating testosterone, luteinizing hormone, follicle-stimulating hormone, or prolactin is altered by unilateral orchidectomy. These data indicate that (1) epididymal 3 alpha-hydroxysteroid dehydrogenase activity can be maintained by circulating androgens and that (2) the major factor regulating delta 4-5 alpha-reductase activity is not a substance secreted by the testes into the peripheral circulation. It is suggested that a substance directly secreted into the epididymis by the testis regulates epididymal delta 4-5 alpha-reductase activity.
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PMID:Effects of unilateral orchidectomy on rat epididymal delta 4-5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase. 51 41

Administration of testosterone, oestrogen, progesterone and prolactin for seven days affected the epididymal lipids markedly whereas seminal vesicular and prostatic lipids were less affected. The increase in total lipids of caput epididymis by testosterone, oestrogen and progesterone was due to an elevation in neutral and phospholipid contents. However, progesterone alone caused an increase in total lipids of the cauda epididymides while oestrogen and prolactin decreased the same. In seminal vesicle and prostate, testosterone elicited a significant rise in total lipids. However, an opposite trend was obvious by the other three hormones. Testosterone alone was effective in elevating the total lipids, phospholipid, cholesterol and glycerides in prostates. Prolactin does not affect the prostatic lipids markedly. The significance of the lipid changes are discussed in relation to various physiological activities of sex accessories.
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PMID:Influence of hormones on accessory sex glands in males. 52 Nov 21

Impact of altered serum prolactin status on enzymes involved in glycoprotein metabolism in epididymal tissue of matured monkeys was studied. Hyperprolactinemia (ovine prolactin-250 micrograms/kg body weight/day for 30 days) significantly inhibited the specific activities of dolichylphosphate mannosyl transferase, dolichylphosphate glucosyl transferase and galactosyl transferase, in the epididymal tissues. However, it had an enhanced effect on epididymal glycosidases such as beta-galactosidase, beta-N-acetyl glucosaminidase, beta-N-acetyl galactosaminidase, alpha-mannosidase and alpha-L-fucosidase. Hypoprolactinemia (bromocriptine mesylate-1-mg/kg body weight/day for 30 days) on other hand had no significant effect on the specific activities of both, glycosyltransferases and glycosidases, in the epididymal tissues. The results suggest that hyperprolactinemia inhibits epididymal glycoprotein metabolism by impairing the incorporation of oligosaccharide units into proteins with enhanced degradation. This may have adverse effect on events leading to sperm maturation in epididymal environment.
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PMID:Role of prolactin on epididymal glycoprotein metabolism in matured monkeys, Macaca radiata: specific activities of glycosyltransferases and glycosidases. 129 32

Onset of sexual maturation was determined in weanling male collared lemmings exposed to one of three experimental regimens of different photoperiods before and after weaning. Animals gestated in photoperiods of either 16 h light:8 h dark or 8 h light:16 h dark. Those from 16 h light:8 h dark were transferred at 19 days of age to either 20 h light:4 h dark or 8 h light:16 h dark; those gestated under 8 h light: 16 h dark remained in that photoperiod throughout the experiment. After exposure for 15, 20, 25 or 30 days to the postweaning photoperiod, animals were killed and the following parameters assessed: body weight, testes weight, seminal vesicle weight, the presence or absence of epididymal spermatozoa and serum concentrations of prolactin, testosterone and corticosterone. All parameters except serum testosterone were significantly influenced by photoperiod. Animals housed under 8 h light:16 h dark had significantly greater body weights than those housed under 20 h light:4 h dark, a response that differs from that reported for other arvicoline rodents. The group gestated on 16 h light:8 h dark and transferred on day 19 to 8 h light:16 h dark had lower testes and seminal vesicle weights than the other two groups, and mature spermatozoa in the epididymides appeared 5 days later than in the 20 h light:4 h dark group. Serum prolactin was largely undetectable in animals from both 8 h light:16 h dark groups, but all males housed in 20 h light:4 h dark had 2.0-15.0 ng prolactin ml-1. Concentration of serum corticosterone was higher in animals weaned into long photoperiod, and decreased with age. These data indicate that weanling male D. groenlandicus are reproductively photoresponsive, but use a decrease in photoperiod, not static short-photoperiod exposure, to alter the rate of development. Prolactin was largely undetectable in animals exposed to short photoperiod, indicating that high concentrations of this hormone are not important for maturation. Low prolactin concentrations in animals in short photoperiods may mediate the annual moult to white pelage. The short-photoperiod-mediated decrease in corticosterone may play a role in seasonal changes in body weight and composition.
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PMID:Role of photoperiod in reproductive maturation and peripubertal hormone concentrations in male collared lemmings (Dicrostonyx groenlandicus). 143 46

1. Previous experiments have shown that the level of sialic acid in the epididymis is influenced by factors originating in the testis. 2. To exclude interference from these factors, both orchidectomized and duct-ligated rats were used to study the potential role of prolactin in the epididymis. 3. When ovine prolactin was injected in orchidectomized rats, a dose-related increase in the level of sialic acid was observed in the epididymis. 4. That this action of prolactin is independent of androgen was confirmed by studies using bromocriptine, which decreases circulating endogenous prolactin. 5. The physiological role(s) of epididymal sialic acid production in response to prolactin remain to be established.
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PMID:The effect of ovine prolactin on the epididymal sialic acid concentration in male rats. 149 47

The effects of lesions (x) of the suprachiasmatic nucleus (SCN) or paraventricular nucleus (PVN), or pinealectomy (PINX) on gonadal recrudescence, body and fat pad weights, and food intake were examined in photoregressed male Siberian hamsters (Phodopus sungorus sungorus). Blood was sampled weekly for serum follicle-stimulating hormone (FSH) and prolactin (PRL) measurement. Lesions were classified as complete if greater than 80% of the nuclei were destroyed and designated as 'hits', whereas incomplete lesions were designated as 'misses'. Five weeks postlesion, hamsters with PVNx or SCNx hits and SCNx misses (lesions generally located caudal and dorsal to the SCN) had increased testes, epididymal white adipose tissue and body weights, increased food intake, and progressively increasing serum PRL, but not FSH concentrations compared with PINX, PVNx misses and intact short day controls. SCNx hamsters with complete lesions had sparse or arrhythmic locomotor activity patterns in subsequent tests under constant conditions. Although no single area was identified histologically as the locus for this effect, the hyperprolactinemia and rapid gonadal recrudescence was consistent with varied degrees of damage to the periventricular area. These results suggest a novel central control of PRL secretion by an area caudal and dorsal to the SCN, and extending to and including the PVN. This area may be involved with maintaining short day responses.
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PMID:Rapid gonadal recrudescence and body and lipid mass increases with hypothalamic lesions in photoregressed Siberian hamsters. 158 38

Reproductive performance was studied in transgenic males from lines expressing and transmitting four hybrid genes: mouse metallothionein-I/human growth hormone (GH) (MT/hGH), MT/hGH placental variant (MT/hGH.V), MT/bovine GH (MT/bGH) and phosphoenolpyruvate carboxykinase/bGH (PEPCK/bGH). Each male was exposed to three normal females for 1 week and to three different normal females for another week. Females were examined for vaginal plugs and necropsied on day 14 of pregnancy. Males were killed for analysis of organ weights, numbers of testicular spermatids, numbers of epididymal sperm and measurements of plasma glucose concentration. Fertility of MT/hGH and MT/hGH.V transgenic males was significantly lower than in normal males, primarily because most males failed to impregnate any females. In females that became pregnant, the numbers of corpora lutea, total fetuses and live fetuses did not differ from those in females mated to normal (nontransgenic) males. Fetal crown-rump length on day 14 of pregnancy did not differ between litters sired by normal or by transgenic males. Weights of testes and seminal vesicles were significantly greater in all four types of transgenic male, but daily sperm production per unit weight (g-1) of testis was not affected and epididymal sperm reserves were either normal or slightly higher than normal. Plasma glucose concentrations were significantly higher in PEPCK/bGH mice than in other mice. Average or individual reproductive performance of transgenic males from the various lines did not correlate with any of the parameters examined except for significantly heavier seminal vesicles in MT/hGH and MT/hGH.V males than in normal males; these transgenic males exhibited a high incidence of infertility. Since hGH and hGH.V, but not bGH, are lactogenic in rodents, it was concluded that chronic stimulation of GH and prolactin receptors by ectopically produced human GHs in transgenic mice compromises male fertility by an unknown mechanism. Reduced fertility of transgenic males with MT/hGH or MT/hGH.V hybrid genes is due to failure to inseminate or impregnate females rather than to reduced numbers of spermatozoa or gross changes in the male reproductive system.
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PMID:Effects of expression of human or bovine growth hormone genes on sperm production and male reproductive performance in four lines of transgenic mice. 162 26

Blood samples were obtained each month for 18 months in 1984-85 from wild-caught California ground squirrels. Circulating testosterone and total oestrogens were extracted from the plasma, measured by radioimmunoassay and compared with concurrent changes in plasma progesterone and prolactin in the same individuals. Male plasma testosterone concentrations peaked in January, shortly before mating, whereas female testosterone concentrations were low throughout the year. Female plasma oestrogen concentrations peaked in February, during the mating period. Juvenile males exhibited a transient increase in circulating testosterone in September, followed by testis growth, preputial separation, and the appearance of epididymal spermatozoa. Juvenile females exhibited a transient increase in circulating oestrogens in November. By the start of the first mating season after their births, neither juvenile males nor females differed significantly from same-sex adults with respect to plasma concentrations of oestrogen or testosterone. Plasma concentrations of progesterone and prolactin in killed individuals were similar to those obtained in previous studies of free-living S. beecheyi. Mean plasma concentrations of all measured hormones varied significantly with reproductive condition in adults of both sexes.
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PMID:Seasonal variation in circulating testosterone and oestrogens of wild-caught California ground squirrels (Spermophilus beecheyi). 178 61

Prolactin and alpha-1,4-glucosidase levels in seminal plasma were measured in poorly coagulated (I), deficiently coagulated (II) and normally coagulated (III and IV) human ejaculates having 0-20%, 21-50% and 51-100% coagulum respectively 4 min after emission. The prolactin concentration (ng ml-1, mean +/- SEM) in poorly coagulated (5.2 +/- 0.48) and deficiently coagulated (7.6 +/- 0.72) samples was significantly lower than in the normally coagulated groups III (51-75% coagulum, 8.2 +/- 0.43) and IV (76-100% coagulum, 9.9 +/- 0.59) as well as the presumably fertile samples (9.2 +/- 0.74). A highly significant positive correlation was observed between the prolactin level and the percentage coagulum of the ejaculates (r = 0.686, n = 58, P less than 0.001). In contrast, the epididymal marker, alpha-glucosidase showed no relationship to seminal coagulation.
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PMID:Prolactin and alpha-1,4-glucosidase activity in normal and poorly coagulated human semen. 206 61


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