Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The use of neuropharmacological agents in neuroendocrine studies has had a significant impact on our knowledge about the neurotransmitter systems that are involved in the control of prolactin secretion. Selective drugs have played a key role in the identification of the dopaminergic inhibitory and serotonergic stimulatory influences. With the development of additional specific neuropharmacological agents in the future, we can expect to gain a better understanding of the complex neural interrelationships involved in the control of anterior pituitary hormone secretion. In view of what we already know about the neurotransmitters involved in the control of prolactin release, a tentative neuronal configuration can be proposed. The following neuronal network most probably does not include several components that may be shown by future studies to be involved in prolactin control, but it does represent a possible functional network based on what knowledge is at the present time (Fig. 4).
Curr Top Mol Endocrinol 1976
PMID:Neuropharmacological aspects of the neural control of prolactin secretion. 2 6

Populations of normal anterior pituitary cells enriched in thyrotrophs or mammotrophs prepared by velocity sedimentation were used to investigate the effect of modulators of TSH and prolactin secretion on cyclic AMP accumulation. In both thyrotroph-enriched and mammotroph-enriched fractions, IBMX increased cyclic AMP accumulation. In the presence of IBMX, TRH invoked an increase in cyclic AMP suggesting that TRH modulates cyclic AMP accumulation in both of these cell types from normal pituitary glands. In the mammotroph-rich fraction, dopamine inhibited the increase in cyclic AMP induced by TRH. In contrast however, in the thyrotroph-enriched fraction dopamine lowered neither cyclic AMP concentration nor TSH secretion. Thus the inhibiting effect of dopamine on cyclic AMP appears to be specific for prolactin-secreting cells.
Mol Cell Endocrinol 1978 Dec
PMID:Effect of TRH and dopamine on cyclic AMP levels in enriched mammotroph and thyrotroph cells. 8 46

Thyroliberin (THR) binds specifically to SD1 rat prolactin cells and increases prolactin release. THR-induced modifications of surface membrane of intact SD1 cells were looked for, using concanavalin A (Con A) as a probe. At the electron microscope level the binding was restricted to the cell surface. Preexposure of the cells to TRH (27 nM) for 30 min at 37 degrees C increased the binding of Con A by 28--120%. Such an increase was not observed with low doses of TRH (13.5 and 2.7 nm) nor after only a 10-min exposure to 27 nM TRH. This effect is specific for TRH; it was not observed with other peptiDES. Simultaneous exposure to Con A and [3H] TRH did not alter [3H]TRH binding, but preexposure to Con A reduced the [3H]TRH binding by 10%, which may be due to steric hindrance. It is concluded that TRH induces an increased exposure of surface membrane glycoproteins in intact SD1 cells.
Mol Cell Endocrinol
PMID:Increased binding of concanavalin A at the cell surface following exposure to thyroliberin. 9 65

Exposure of mouse mammary gland explants to prolactin at 0 degrees C, for periods as brief as 10 seconds, caused a stimulation of labeled uridine incorporation into RNA during a subsequent incubation for 4 h at 37 degrees C. Furthermore, a 2-h wash of the prolactin-exposed explants in media at 0 degrees C did not attenuate the hormonal effect. A similar exposure of explants to insulin, followed by a 2-h wash at 0 degrees C, caused the abolition of the insulin stimulation of labeled uridine incorporation into RNA. The results suggest that there is a rapid and relatively stable interaction of prolactin with the mammary gland, while the interaction of insulin with this tissue would appear to be less stable.
Mol Cell Endocrinol 1976 Feb
PMID:Rapid interaction of prolactin with mouse mammary gland explants. 17 63

Specific receptors for [125I]hPrl (human prolactin) are present in membrane preparations of rat testis. The receptors are specific for lactogenic hormones (prolactin and human growth hormone) but do not bind gonadotropins. The prolactin receptors are localized exclusively in the interstitial cell tissue, and are not present in membrane preparations from isolated seminiferous tubules. The localization of prolactin receptors interstitial tissue suggests that the effect of prolactin on LH/hCG-stimulated testosterone production is due to a direct effect of prolactin of Leydig cells.
Mol Cell Endocrinol 1977 Feb
PMID:Prolactin binding in rat testis: specific receptors in interstitial cells. 19 66

Specific receptors for iodine-labelled human prolactin ([125I]hPrl) are present in membrane preparations of the rat ventral prostate. The binding is saturable with an apparent association constant (Ka) of 2.2 X 10(9) M-1 and a binding capacity of about 1 pmol/100mg prostatic tissue. The binding of [125I]hPrl is inhibited by hPrl, ovine Prl (otprl) and human growth hormone, but not by ovine FSH or LH. Serum from rats having Prl-producing pituitary tumors caused a displacement of the [125I]hPrl from the receptors, and the displacement curve was parallel with that of the hPrl standard. Treatment of immature rats with varying doses of dihydrotestosterone propionate (10-5000 microng) causes a dose-dependent stimulation of Prl receptors calculated both as binding sites per mg of membrane protein and as binding sites per prostate. Androgen stimulation of prostatic Prl receptors increases the tissue sensitivity for circulating Prl and may be one reason for the known increases in endogenous cAMP levels in prostatic tissue after androgen treatment in vivo.
Mol Cell Endocrinol 1977 Mar
PMID:Androgen stimulation of prolactin receptors in rat prostate. 19 11

Significantly (P less than 0.01) reduced 125I-labeled ovine prolactin binding (mean, --22%), as a result of an ether anesthesia-reduced rise in serum prolactin, was observed in plasma membrane preparations of liver samples of female rats taken after 5 min of etherization when compared to samples taken from the same animals during the first minute of etherization. This reduction in assayable receptors occurred after 1 h but not 2 h of assay incubation time. Significantly (P less than 0.05) reduced 125I-labeled ovine prolactin binding (mean, --16%) was also observed in liver samples exposed to a 30-min ether-induced rise in serum prolactin when compared to liver samples taken during the first minute of etherization. In contrast, this reduction was apparent at assay incubation times of 1, 2 and 4 h but not at 10 h. These results suggest that serum prolactin can bind to prolactin receptors in vivo and partially block subsequent 125I-labeled ovine prolactin receptor assay. In addition, these data provide evidence that a complex time-dependent binding of prolactin may occur in the plasma of the female rat liver.
Mol Cell Endocrinol
PMID:Effect of the association time of in vivo bound prolactin on the [125I]prolactin receptor assays of female rat livers. 21 63

Modulation of specific binding of prolactin to murine mammary gland as a response to treatment with various doses of estradiol benzoate (EB) was studied. Measurements of serum and pituitary levels of prolactin were also carried out simultaneously. Estradiol benzoate at a dose of 5 microgram significantly increased the binding of 125I-labelled rat prolactin (rPRL) to mammary gland concomitant with increased serum prolactin levels in ovariectomized mice. Administration of bromoergocryptine along with EB resulted in decreased serum prolactin levels as well as binding of prolactin to breast tissue. It thus appears that the influence of estradiol on binding of prolactin to mammary gland is mediated primarily via its property of enhancing serum prolactin concentration apart from its possible direct effect at the target tissue level.
Mol Cell Endocrinol 1978 Nov
PMID:Influence of bromoergocryptine on estrogen-modulated prolactin receptors of mouse mammary gland. 21 74

Properties of prolactin receptors were measured by monitoring [125I]prolactin binding to specific receptor sites on collagenase-dissociated mammary epithelial cells of virgin, pregnant and lactating mice. On a Scatchard plot the data generated a straight line and the estimated dissociation constant (Kd) and number of receptor sites on lactating cells were 0.9 x 10(-9) and 1540 per cell. The [125I]prolactin binding was inhibited in presence of unlabeled prolactin and other lactogenic polypeptide hormones, but not by nonlactogenic polypeptide hormones. The [125I]prolactin binding was sensitive to pronase and trypsin but not to DNAase, RNAase and hyaluronidase. Scatchard plot analysis further showed that while the number of receptors on mammary cells was variable at different stages of endocrine regulated developmental changes of the gland, Kd of the hormone--receptor complex generally remained similar. The high level of prolactin receptors on mammary cells of virgins was reduced during pregnancy and the lactating mammary cells showed a highly elevated level of prolactin receptors. The results demonstrate that specific prolactin receptors can be measured on collagenase dissociated mammary epithelial cells and this method permits a direct assessment of the number of receptors on a per cell basis rather than indirect estimates, based on average DNA or protein content of the tissue, composed of heterogeneous cell types.
Mol Cell Endocrinol 1978 Dec
PMID:Prolactin receptor on dissociated mammary epithelial cells at different stages of development. 21 95

Inhibition of plasma prolactin levels by 2-bromo-alpha-ergocryptine (CB-154) caused a 60% decrease and potentiated the inhibitory effects of [D-Ala6,des-Gly-NH2(10)]LHRH ethylamide on testicular LH receptor levels. Animals treated with the LHRH agonist showed reduced plasma and testicular testosterone levels and elevated progesterone concentration. This progesterone rise was further increased in animals having high circulating prolactin levels but was prevented by CB-154. These data demonstrate that: (1) treatment with the LHRH agonist induces a blockage in the steroidogenic pathway at a step between progesterone and testosterone and (2) prolactin levels to an apparent accentuation of this blockage reflected by higher progesterone levels.
Mol Cell Endocrinol 1979 Jan
PMID:Down-regulation of testicular androgen biosynthesis and LH receptor levels by an LHRH agonist: role of prolactin. 22 Dec 86


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