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

The acute metabolic actions of insulin-like growth factor I were studied in anaesthetized adult rats and its potency was compared to that of insulin. Following an i.v. bolus injection of insulin-like growth factor I a dose-dependent decrease of blood glucose and serum non-esterified fatty acid concentrations was noted with a potency of about 2% that of insulin. Stimulation of total body glucose disposal during euglycaemic clamping required approximately 50 times higher insulin-like growth factor I serum concentrations to achieve an identical half-maximal response. A similar difference in potency was observed for the stimulatory action on 2-deoxyglucose uptake and on glycogen formation in skeletal muscle. Lipogenesis in epididymal fat pads was increased dose-dependently by both hormones requiring approximately 30 times higher half-maximally effective serum concentrations of insulin-like growth factor I. These data demonstrate that insulin-like growth factor I exerted acute insulin-like metabolic actions in vivo with low potency. These effects were probably mediated via insulin receptors. A preferential stimulation of glucose metabolism in skeletal muscle was not observed.
 ...
PMID:In vivo metabolic action of insulin-like growth factor I in adult rats. 188 85

Recombinant human insulin-like growth factor I (rhIGF-I) was infused subcutaneously into hypophysectomized rats for as long as 18 days. Three hundred micrograms (39 nmol) of rhIGF-I per day and 200 milliunits (4.5 nmol) of human growth hormone (hGH) per day increased body weight, tibial epiphyseal width, longitudinal bone growth, and trabecular bone formation similarly. Weight gains of the kidneys and spleen, however, were greater with rhIGF-I than with hGH, whereas the weight of the epididymal fat pads was reduced with rhIGF-I. The weight of the thymus was increased by rhIGF-I treatment. Thus, IGF-I administered over a prolonged period of time mimics GH effects in hypophysectomized rats. Quantitative differences between rhIGF-I and hGH treatment with respect to organ weights may be related to different forms of circulating IGF-I or may be due to independent effects of GH and IGF-I. The results support the somatomedin hypothesis, but they also stress the role of GH as a modulator of IGF-I action.
 ...
PMID:Recombinant human insulin-like growth factor I stimulates growth and has distinct effects on organ size in hypophysectomized rats. 338 45

The distribution and density of functional insulin-like growth factor I (IGF-I) receptors in cryptorchid and scrotal rat testes and epididymides during gonadal development were studied. Cryptorchidism was induced by unilateral gubernaculectomy in 4-day-old animals, and organs were studied at 15, 30, 60 and 90 days of age. Tissue membranes were assayed for 125I-labelled IGF-I binding. Characterization and specificity of binding sites showed that both normal and contralateral undescended testes and epididymides exhibited typical type 1 IGF receptors. In normal testes, IGF-I receptor density was 20.6 nmol g-1 wet mass at day 15, and decreased to 12.8 nmol g-1 wet mass at adult age (day 90). Cryptorchid testes showed IGF-I receptor concentrations similar to normal testes at day 15 and day 30, but in postpubertal stages displayed a divergent pattern, with a continuous increase at day 60 and day 90, reaching a higher density than those found for immature ages (62 nmol g-1 wet mass). Both normal and cryptorchid epididymides had a similar concentration and a comparable decrease in IGF-I receptors throughout development. In studies with immunohistochemical techniques (alpha IR-3 antibody), IGF-I receptors were found in primary spermatocytes, Sertoli cells and Leydig cells. Cryptorchid tubules showed a lack of germinal epithelium and a marked increase of immunoreactive IGF-I receptors in Sertoli cells, compared with normal tubules from scrotal testes. Intense immunoreactivity for IGF-I receptors was present in the principal cells of epididymal tubules in both normal and cryptorchid organs.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effect of testicular damage induced by cryptorchidism on insulin-like growth factor I receptors in rat Sertoli cells. 747 18

The distribution of insulin-like growth factor I (IGF-I) was studied by immunohistochemistry during postnatal development of the rat epididymis. At 2 weeks the immunoreactivity was mainly located along the cytoplasmic apical border in both the caput and the cauda epididymidis. A slight immunolabeling was present in the myofibroblastic cells. Afterward, the epithelial immunoreactivity was minimal at 4 weeks and increased progressively after the 6th week, especially in the apical and subapical cytoplasmic compartments of the caput epididymidis. The labeling of the epithelial cells of the cauda epididymidis was restricted to the apical cytoplasmic area. Immunolabeling was also found in the myofibroblastic cells and was more intense after 6 weeks. The variations of the pattern of distribution support the hypothesis of a physiological role for IGF-I in the regulation of epididymal functions.
 ...
PMID:Immunohistochemical localization of insulin-like growth factor I (IGF-I) in the rat epididymis. 840 69

Human and rat pineal melatonin secretion decline with aging, whereas visceral fat and plasma insulin levels increase. Melatonin modulates fat metabolism in some mammalian species, so these aging-associated melatonin, fat and insulin changes could be functionally related. Accordingly, we investigated the effects of daily melatonin supplementation to male Sprague-Dawley rats, starting at middle age (10 months) and continuing into old age (22 months). Melatonin was added to the drinking water (92% of which was consumed at night) at a dosage (4 microg/ml) previously reported to attenuate the aging-associated decrease in survival rate in male rats, as well as at a 10-fold lower dosage. The higher dosage produced nocturnal plasma melatonin levels in middle-aged rats which were 15-fold higher than in young (4 months) rats; nocturnal plasma melatonin levels in middle-aged rats receiving the lower dosage were not significantly different from young or middle-aged controls. Relative (% of body wt) retroperitoneal and epididymal fat, as well as plasma insulin and leptin levels, were all significantly increased at middle age when compared to young rats. All were restored within 10 weeks to youthful (4 month) levels in response to both dosages of melatonin. Continued treatment until old age maintained suppression of visceral (retroperitoneal + epididymal) fat levels. Plasma corticosterone and total thyroxine (T4) levels were not significantly altered by aging or melatonin treatment. Plasma testosterone, insulin-like growth factor I (IGF-I) and total triiodothyronine (T3) decreased by middle age; these aging-associated decreases were not significantly altered by melatonin treatment. Thus, visceral fat, insulin and leptin responses to melatonin administration may be independent of marked changes in gonadal, thyroid, adrenal or somatotropin regulation. Since increased visceral fat is associated with increased insulin resistance, diabetes, and cardiovascular disease, these results suggest that appropriate melatonin supplementation may potentially provide prophylaxis or therapy for some prominent pathologies associated with aging.
 ...
PMID:Daily melatonin administration at middle age suppresses male rat visceral fat, plasma leptin, and plasma insulin to youthful levels. 992 36

To examine whether insulin-like growth factor I (IGF I) or growth hormone (GH) influences leptin in vivo we measured leptin mRNA in epididymal fat pads and serum leptin of normal rats infused subcutaneously for 6 days with recombinant human (rh)IGF I (1 mg/day), rhGH (200 mU/day), or vehicle. In addition, we determined fat pad weight and food consumption as well as IGF I, insulin, glucose, non-esterified fatty acid (NEFA), glycerol, beta-hydroxybutyrate and triglyceride (TG) serum concentrations. Food intake was identical during all three treatments. RhIGF I but not rhGH raised IGF I serum concentrations, reduced fat pad weight (60.3 +/- 7.4% of control rats, p = 0.019), and suppressed leptin mRNA (38.8 +/- 11.9% of control rats, p = 0.002), serum leptin (51.6 +/- 10.5% of control rats, p = 0.0028) and serum triglycerides (39.3 +/- 8.0% of control rats, p = 2.6 x 10(-6)). Both rhIGF I and rhGH reduced non-esterified fatty acids (NEFA) (p = 0.00001 and 0.0007, respectively), whereas serum glycerol, beta-OH butyrate and glucose concentrations remained unchanged. Serum insulin concentrations during rhIGF I were lower than during rhGH infusion and correlated with leptin mRNA (r = 0.589, p = 0.016) and fat pad weight (r = 0.643, p = 0.007). Reduction of adipose tissue mass and suppression of leptin by IGF I appear to be due to reduced circulating insulin leading to enhanced fat mobilization and NEFA oxidation as well as to increased gluconeogenesis from glycerol. In contrast, decreased NEFA concentrations during rhGH in the presence of unchanged fat pad weight, serum glycerol and triglycerides might result from more efficient re-esterification of released fatty acids within the triglyceride-fatty acid cycle. The results also show that exogenously infused IGF I and GH act on lipid metabolism by different mechanisms and suggest an IGF-independent, probably direct, metabolic effect of GH. Finally, in agreement with previous studies in GH-infused hypophysectomized rats, it appears unlikely that GH regulates leptin in the rat.
 ...
PMID:Leptin is suppressed during infusion of recombinant human insulin-like growth factor I (rhIGF I) in normal rats. 1006 95

It has been proposed that a global decline in sperm counts, semen quality, and several male reproductive disorders are associated with exposure to environmental chemicals. Thus, the present study examined the effects of two estrogenic chemicals, octylphenol (OP) and bisphenol A (BPA), on epididymal sperm counts and sperm motility, luteinizing hormone (LH)-releasing hormone (LHRH)-stimulated plasma LH and steroid hormones, insulin-like growth factor I (IGF-I), and accessory reproductive organs in pubertal male Wistar rats. Fifty-day-old rats in the OP group (n=11) and BPA group (n=11) received daily sc injections of the respective chemical at a dose of 3 mg/kg bw dissolved in 0.2 mL DMSO. Rats in the control group (DMSO group; n=10) received 0.2 mL DMSO alone. After 2 wk of treatment, a jugular blood sample was taken, and, on the next day, a second blood sample was taken 1 h after an sc injection of LHRH (250 ng). After 5 wk of treatment, rats were deeply anesthetized and heart blood was collected. Epididymal sperm motility and sperm head counts were determined. LHRH increased plasma LH to higher levels in all groups, but the increases were significant (p<0.01) in the BPA and OP groups. However, despite higher LH levels after LHRH injection, the incremental responses of testosterone and pro-gesterone in the OP and BPA groups were small compared to those in the DMSO group, which showed a small LH response. After 5 wk of treatment, plasma testosterone levels were significantly (p<0.01) reduced in the OP and BPA groups and this was accompanied by reduced (p<0.05) epididymal sperm counts. However, the chemical-treated groups had high basal progesterone levels. No significant effects of chemicals on sperm motility parameters were noted. The chemical-induced increases (p<0.05) of the weight of ventral prostate gland were coincided with elevated plasma IGF-I levels in the BPA (p<0.05) and OP (p<0.01) groups. The present results demonstrated that OP and BPA can reduce sperm counts resulting from lowered plasma testosterone in male rats just after puberty. The enlarged ventral prostate gland may possibly be associated with increased plasma IGF-I, raising the possibility of a link between these chemicals and prostate diseases because IGF-I has been implicated in the pathogenesis of human prostate cancers.
 ...
PMID:Adverse effects of environmental toxicants, octylphenol and bisphenol A, on male reproductive functions in pubertal rats. 1571 Oct 31