Disease relevance of prl

• These conclusions are drawn from experiments using exogenous prolactin and vesicular stomatitis virus G protein (VSV G) encoded by SP6 transcripts and endogenous glycosaminoglycan (GAG) chains initiated on beta-D-4-methylumbelliferyl-xyloside [1].

High impact information on prl

• In contrast, GThy-1 and prolactin, when expressed in embryos, are inserted or released at both the outer membrane derived from the oocyte and the inner cleavage membranes [2].
• Using prolactin as a marker, we found that a subset of vesicles synthesized during oogenesis was only released after fertilization [2].
• Oogenic prolactin was secreted only into the blastocoel (from the cleavage membrane), none could be detected in the external medium (from the original oocyte membrane) [2].
• The pituitary gland of a premetamorphic tadpole expresses PRL mRNA at very low levels [3].
• Arginine vasopressin modulates the release of adrenocorticotropic hormone, beta-endorphin, and prolactin from the anterior pituitary [4].

Biological context of prl

• As the truncation mutant was unable to activate transcription from the chromatin-assembled template, the ability of Pit-1 to alter chromatin structure of the prolactin gene is not dependent on transcriptional activation [5].
• PRL arrested further morphogenesis and regression of these two tissues, respectively [6].
• We have recently reported that prolactin (PRL) inhibits both morphogenesis and cell death in thyroid hormone (T3)-induced amphibian metamorphosis (Tata et al., 1991), and that the autoinduction of T3 receptor (TR alpha and beta) mRNA is among the most rapid responses of premetamorphic Xenopus tadpoles to T3 (Kawahara et al., 1991) [7].
• We now demonstrate that PRL prevents the rapid T3-induced upregulation of TR alpha and beta mRNAs in stages 50-54 Xenopus tadpoles and in organ cultures of tadpole tails [7].
• The precocious induction in vivo and in culture of insect and amphibian metamorphosis by exogenous thyroid hormones, and its retardation or inhibition by prolactin (PRL), have allowed the analysis of such characteristic features of post-embryonic development as morphogenesis, tissue remodelling, gene reprogramming, and programmed cell death [8].

Anatomical context of prl

• From the initiation of maturation with progesterone until GVBD, secretion of prolactin synthesized before the start of maturation is comparable to secretion in immature oocytes, but after GVBD secretion of prolactin declines approximately 63% in the first hour [1].
• In prolactin-deprived animals, androgen-induced changes in the contractile properties of laryngeal muscle are blocked, which prevents the rapid rates of muscle contraction required for males to produce courtship songs [9].
• To our knowledge, the present results provide the first demonstration of the occurrence of prolactin specific binding sites in Xenopus laevis choroid plexus cells [10].
• Hence, a Xenopus PRL-R cDNA was cloned, its structure was characterized, and specific binding of PRL to Xenopus PRL-R expressed in COS-7 cells was confirmed [11].
• The occurrence of prolactin binding sites in some brain structures (telencephalon, ventral hypothalamus, myelencephalon, hypophysis, and choroid plexus) from Xenopus laevis (anuran amphibian) was studied by the in vitro biochemical technique [10].

Associations of prl with chemical compounds

• The abundance of PRL mRNA increases late in metamorphosis as a response to thyroid hormone (TH), suggesting that PRL is more likely to have a function in the frog than in the tadpole [3].
• Melatonin acceleration of metamorphosis may occur through alteration of the concentration of prolactin [12].
• Here, we show that exposure to prolactin is necessary to allow androgen-induced LM expression in postmetamorphic froglets [9].
• Effects of synthetic mammalian thyrotrophin releasing hormone, somatostatin and dopamine on the secretion of prolactin and growth hormone from amphibian and reptilian pituitary glands incubated in vitro [13].
• No clear response of PRL cells to injection of 5-HTP can be observed in Pleurodeles [14].

Other interactions of prl

• Prolactin prevents the autoinduction of thyroid hormone receptor mRNAs during amphibian metamorphosis [7].
• Dopamine had little effect alone, but inhibited HE- and TRH-stimulated release of prolactin, but not GH, in both amphibia and reptiles [13].

Analytical, diagnostic and therapeutic context of prl

• Using this response as a bioassay, we purified the ligand for GRL106, Lymnaea cardioexcitatory peptide (LyCEP), an RFamide-type decapeptide (TPHWRPQGRF-NH2) displaying significant similarity to the Achatina cardioexcitatory peptide (ACEP-1) as well as to the recently identified family of mammalian prolactin-releasing peptides [15].
• It was hypothesized that exogenous melatonin would delay metamorphosis and increase body size, and that elevation of Prl concentrations would have effects similar to melatonin exposure [12].
• Molecular cloning and functional characterization of a prolactin-releasing peptide homolog from Xenopus laevis [16].
• Prolactin and GH concentrations in the medium were determined by densitometry after polyacrylamide-gel electrophoretic separation [13].
• Effects of hypophysectomy and substitution with growth hormone, prolactin, and thyroxine on growth and deposition in juvenile frogs, Xenopus laevis [17].

References