PubMed · 2140473
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P Klarskov, A N Andersen, M Trokmar. 1990-04-30. [Goserelin].. https://pubmed.ncbi.nlm.nih.gov/2140473/
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Regulators of G protein signaling (RGS) act as GTPase-activating proteins for Galpha(i) and for Galpha(q/11). There is recent evidence for interaction of RGS proteins with Galpha(s), and substitution of Ser for Asp(229) in RGS proteins enhances interactions with G proteins. Site-directed mutagenesis of Asp(229) was used to assess the effect of this site on the gonadotropin-releasing hormone receptor (GnRHR)-Galpha(s) mediated signaling in the absence or presence of over-expressed RGS3, RGS10 or a truncated form of RGS3 (RGS3T). We observed increased cAMP release with the mutant Galpha(s)(D(229)S) compared to wt Galpha(s) when GGH(3) cells (GH(3) cells stably expressing the GnRH receptor) were stimulated with a GnRH agonist. In the presence of RGS3, we did not observe any difference in cAMP release with wt Galpha(s) or with Galpha(s)(D(229)S) compared to control values; in the presence of RGS3T there was an increase of cAMP release with wt Galpha(s) compared to the control but there was no difference between the Galpha(s)(D(229)S) and the control values. When cells co-expressed wt Galpha(s) and RGS10, there was a significant increase of cAMP release compared with cells co-expressing wt Galpha(s) and Lac Z. Cells co-expressing Galpha(s)(D(229)S) and RGS10 showed a significant increase of cAMP release compared to control cells. These results indicate differential regulation of the GnRHR-Galpha(s) mediated signaling by a single mutation in Galpha(s) in the presence of RGS10 and RGS3T, but not with RGS3. This is the first report of an effect of the Galpha(s)(D(229)S) mutation on G protein-coupled receptor-mediated activation.
OBJECTIVE: To evaluate the changes taking place in the ovaries during pituitary down-regulation. DESIGN: Prospective observational study of women undergoing IVF treatment. SETTING: A tertiary referral center for assisted reproduction. PATIENT(S): Forty women who received the long buserelin acetate treatment protocol. Transvaginal three-dimensional power Doppler ultrasound examinations before and after pituitary down-regulation. INTERVENTION(S): Ovarian volume, number of follicles, vascularization index (VI), flow index (FI), vascularization flow index (VFI), and mean gray value (MG). RESULT(S): Before the pituitary down-regulation, the dominant ovary was larger in volume and had a lower MG than the nondominant ovary. After the down-regulation, there was a significant decrease in the volume and number of follicles and an increase in MG. After pituitary down-regulation, the dominant and nondominant ovaries did not differ from each other in any of the parameters. Polycystic ovaries were larger than normal ones before and after the down-regulation, without any differences in MG, VI, FI, or VFI. Right and left ovaries did not differ from each other after the down-regulation. CONCLUSION(S): The differences observed between dominant and nondominant ovaries seem to disappear after pituitary down-regulation. In addition, polycystic ovaries were always larger than the normal ones, but no differences could be detected in the stromal brightness or vascularity either before or after the administration of GnRH agonist therapy.
Novel peroral peptide drug delivery systems based on superporous hydrogel (SPH) and SPH composite (SPHC) have recently been developed in our laboratory. In this report the following issues were studied: release of the peptide drugs buserelin, octreotide and insulin from SPH and SPHC polymers and the developed delivery systems, stability of these peptides during the release and the integrity of insulin in the polymeric matrix of SPHC. Release studies from SPH and SPHC polymers revealed that buserelin, octreotide and insulin were released almost completely from the polymers. Peptide release rates from SPH were faster than from SPHC, due to the more porous structure of SPH polymer. All peptides studied in contact with SPHC polymer were stable under different environmental conditions (ambient temperature, 37 degrees C, light and darkness and at pH values 3.2 and 7.2). FTIR studies demonstrated that no covalent binding occurred between insulin and the polymeric SPHC matrix. Release profiles of all peptides from the developed delivery systems showed a time-controlled release profile: after a short lag time of 10-15 min, a burst release of peptides occurred during which more than 80% of peptide was released within 30-45 min. In conclusion, the present delivery systems based on SPH and SPHC show appropriate in vitro properties for application in peroral peptide drug delivery of buserelin, octreotide and insulin, and are therefore promising for further in vivo evaluation.