Comparative stimulatory effect of gonadotrophin releasing hormone (GnRH) and GnRH agonist upon pulsatile human chorionic gonadotrophin secretion in superfused placental explants: reversible inhibition by a GnRH antagonist
| Autor: | Kaplan M, Naor Z, Eytan R. Barnea |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Agonist
Periodicity endocrine system medicine.medical_specialty medicine.drug_class Placenta Molecular Sequence Data Pulsatile flow Gonadotropin-releasing hormone Peptide hormone Chorionic Gonadotropin Gonadotropin-releasing hormone antagonist Gonadotropin-Releasing Hormone Pregnancy Culture Techniques Internal medicine medicine Humans Amino Acid Sequence Exertion reproductive and urinary physiology Chemistry Rehabilitation Obstetrics and Gynecology Endocrinology medicine.anatomical_structure Reproductive Medicine Female Gonadotropin hormones hormone substitutes and hormone antagonists |
| Zdroj: | Human Reproduction. 6:1063-1069 |
| ISSN: | 1460-2350 0268-1161 |
| DOI: | 10.1093/oxfordjournals.humrep.a137485 |
| Popis: | The roles of gonadotrophin releasing hormone (GnRH) and a GnRH agonist (GnRHa) (D-Ala6-Met-Leu7-Pro-N-ethyl-amide) in controlling pulsatile human chorionic gonadotrophin (HCG) secretion by superfused placental explants in the first trimester were examined. One minute pulses of both GnRH and GnRHa had a biphasic effect upon pulsatile HCG secretion. GnRHa was maximally effective at 10(-10) M concentration, at 10(-11) M the effect was mild while at 10(-8) M, no effect was noted. GnRH exerted a maximal stimulatory effect at 10(-8) M; at 10(-10) M no effect was seen, while at 10(-7) M the effect was mildly stimulatory. This was evaluated by carrying out both a between and within channel type of analysis. The effect of a GnRH antagonist GnRH(ant) upon GnRH and GnRHa-induced HCG secretion was examined. Explants were incubated overnight with 10(-8) M GnRH(ant), which was also continuously administered during superfusion. The addition of 1-min pulses of GnRH and GnRHa during the exposure to GnRH(ant) failed to stimulate pulsatile HCG secretion. This effect was reversible since the response to GnRH was restored within 10 min after stopping GnRH(ant) administration. In addition, by the third cycle, co-administration of GnRH(ant) for 2 min together with 10(-10) M GnRHa for 1 min completely blocked the GnRHa-induced effect. Continuous administration of 10(-8) M GnRH(ant) decreased spontaneous HCG pulse amplitude and the area under the curve but failed to modify pulse frequency. In conclusion, GnRH appears to exert a receptor-dependent stimulatory effect upon pulsatile HCG secretion in superfusion in the first trimester placenta.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|