Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive carcinoma in the Wistar/Furth rat is compared. The time course of binding of prolactin at 4, 24, ad 37 degrees for mammary tumor (MTW9) coimplanted with MtTW10, a mammosomatotropic pituitary tumor (MTW9-MtT) or with MTW9 maintained with daily perphenazine injections (MTW9-P) was measured. Maximum binding to membranes of both tumors occurred at 4 degrees after about 30 hours incubation. The binding was inhibited by polypeptide hormones that possess lactogenic activity. Mammary tumors from animals maintained on perphenazine had a 4-fold greater binding capacity than did tumors from MtT-supported animals. When perphenazine therapy was halted the binding capacity of MTW9-P membranes was unaffected. This result held when MTW9-P animals were ovariectomized. Resection of MtT resulted in tumor regression, a fall to normal of serum prolactin, and a nearly 3-fold increase in prolactin binding. Scatchard plots of prolactin binding data yield an apparent affinity constant, K(a) of 1.2 X 10(9) liters/mole for both tumors.
 ...
PMID:Prolactin binding in ovariectomy-responsive and ovariectomy-nonresponsive rat mammary carcinoma. 1 19

Prolactin iodinated by lactoperoxidase method showed immunologically, electrophoretically and biolo9gically similar properties to native prolactin and possessed enough specific radioactivity for receptor studies. 1251-prolactin was incubated with mouse mammary tissues at 8 days of lactation. Both binding and release of 1251-prolactin depended on incubation time and temperature and were maximal at 37 degrees C. Michaelis constant was estimated to be 1.4 X 10(-9) M from Lineweaver-Burk plot and to be 1.2 X 10(-9) M from id-value of the dose-response curve for displacement with native prolactin. Total number of binding sites for prolactin was 1.38 X 10(-15) mole per mg weight of tissue. Ovine prolactin, human growth hormone and human placental lactogen complete with 1251-prolactin and dose-response curves for these three hormones were all parallel. These results suggest the existence of a specific receptor site with high affinity for prolactin in lactating mouse mammary glands.
 ...
PMID:A receptor site for prolactin in lactating mouse mammary tissues. 17 1

Cultured seminal vesicle cells of Gobius niger L., precultured for about 15 days, are tested for their Testosterone-binding capacity. This whole cell system shows a specific binding of the androgen, reaching saturation in the presence of increasing amounts of ligand and the Scatchard Plot indicates a good affinity (KD = 4.4 x 10(-9) M), involving a number of sites of 5.06 x 10(-15) mole/culture. The possible existence of a second binding-site population with lower affinity and greater number of sites remains to be demonstrated. At 18 degrees C, the time course shows a maximal binding after about 60 min. of incubation, followed by a rapid decline at 90 min. The competition experiments involving estradiol, 11-keto- and 11-hydroxytestosterone indicate an effective if not total specificity to these steroids. The cross-reaction percentages at the 50% binding level are respectively 10.9, 8.5, 4.02%. Ovine Prolactin treatment of the cultures for 6 days before the binding experiment significantly improves the specific binding level of testosterone if compared to the controls (p .019, p .005). This result indicates that the Prolactin-Testosterone synergistic data already obtained on the seminal vesicles of Siluridae and Gobiidae is explained by a direct effect of the Prolactin on the androgen receptor level in the seminal vesicle cell.
 ...
PMID:[Prolactin and specific binding of testosterone in cultured cells of the seminal vesicle of Gobius niger L]. 251 69

The eusocial Damaraland mole-rat (Fukomys damarensis) represents an extreme example of reproductive skew, in that reproduction is completely blocked in female subordinate group members. It is thought that in these animals normal GnRH secretion from the hypothalamus is disrupted. Prolactin, a peptide hormone secreted from the anterior pituitary gland, has been implicated in a wide variety of functions. Well documented in rodents is its role in mediating lactational infertility. Elevated circulating prolactin levels, such as during lactation, are associated with reduced GnRH release into the portal blood and with a reduction in the frequency and amplitude of LH pulses. The present study aimed at investigating whether such a mechanism could act in reproductively suppressed female Damaraland mole-rats. By means of in situ hybridisation we studied the distribution and gene expression of the prolactin receptor (Prlr) in wild-caught female Damaraland mole-rats with different reproductive status. Substantial Prlr expression was found in several brain regions, with highest levels in the choroid plexus and moderate expression in the preoptic and tuberal hypothalamus. While in reproductive and non-reproductive females plasma prolactin levels were very low and not significantly different, quantification of the Prlr hybridisation signal revealed significant differences in relation to reproductive status. Reproductively suppressed females had increased expression of Prlr in the choroid plexus and in the arcuate nucleus (ARC) when compared to reproductive females. This suggests higher local prolactin levels in the brain of suppressed females. Together with previous findings, it could indicate that prolactin inhibits ARC kisspeptin neurons, which then would lead to reduced activation of GnRH neurons in such females.
 ...
PMID:Reproductive status affects the expression of prolactin receptor mRNA in the brain of female Damaraland mole-rats. 3011 54