Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
IS GNRH REDUCED AT THE MIDCYCLE SURGE IN THE HUMAN - EVIDENCE FROM A GNRH-DEFICIENT MODEL
Autore:
MARTIN KA; WELT CK; TAYLOR AE; SMITH JA; CROWLEY WF; HALL JE;
Indirizzi:
MASSACHUSETTS GEN HOSP,REPROD ENDOCRINE UNIT,NATL CTR INFERTIL RES,BARTLETT HALL,FRUIT ST BOSTON MA 02114 MASSACHUSETTS GEN HOSP,DEPT MED,REPROD ENDOCRINE SCI CTR BOSTON MA 02114
Titolo Testata:
Neuroendocrinology
fascicolo: 6, volume: 67, anno: 1998,
pagine: 363 - 369
SICI:
0028-3835(1998)67:6<363:IGRATM>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
GONADOTROPIN-RELEASING-HORMONE; HUMAN MENSTRUAL-CYCLE; RAT ESTROUS-CYCLE; LUTEINIZING-HORMONE; RHESUS-MONKEY; OVARIECTOMIZED EWES; PITUITARY-RESPONSIVENESS; PERIOVULATORY PERIOD; PULSATILE RELEASE; PULSE FREQUENCY;
Keywords:
GONADOTROPINS; GONADOTROPIN-RELEASING HORMONE; GONADAL STEROIDS; ESTROUS CYCLE; CLINICAL NEUROENDOCRINOLOGY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
51
Recensione:
Indirizzi per estratti:
Citazione:
K.A. Martin et al., "IS GNRH REDUCED AT THE MIDCYCLE SURGE IN THE HUMAN - EVIDENCE FROM A GNRH-DEFICIENT MODEL", Neuroendocrinology, 67(6), 1998, pp. 363-369

Abstract

Recent studies indicate that the midcycle gonadotropin surge in the human occurs without an increase in hypothalamic gonadotropin-releasinghormone (GnRH) pulse frequency. In addition, previous studies employing a GnRH antagonist to provide a semiquantitative estimate of endogenous GnRH secretion suggest that the overall amount of GnRH secreted isdecreased at the time of the surge. To investigate the hypothesis that a normal gonadotropin surge can be generated in the human with a decreased amount of GnRH at the midcycle, 7 GnRH-deficient subjects underwent two cycles of a physiologic regimen of intravenous pulsatile GnRHtherapy. In the control cycle, 75 ng/kg/bolus of GnRH, a dose known to be sufficient for folliculogenesis, was administered throughout the cycle, using physiological frequencies. In a second cycle, the bolus dose of GnRH was decreased by one-half log order to 25 ng/kg just priorto the luteinizing hormone surge and returned to 75 ng/kg after documented ovulation, All cycles were ovulatory. The peak luteinizing hormone level (77.4 +/- 9.7 vs. 67.5 +/- 17.6 IU/l) did not differ between the control and decreased GnRH cycles. There was no difference in the peak serum estradiol level (475.8 +/- 144.1 vs. 493.2 +/- 93.0 pg/ml),follicular phase length (15.0 +/- 1.3 vs. 14.8 +/- 0.6 days), or progesterone level (22.4 +/- 5.1 vs. 34.8 +/- 5.7 ng/ml) on day 6 of the luteal phase in the control and decreased GnRH cycles, respectively. Three pregnancies were achieved in each of the control and reduced GnRH cycles. We conclude that a decreased overall amount of GnRH generates a normal midcycle gonadotropin surge and has no significant impact on luteal phase adequacy or fertility. These results provide further evidence that a decrease in endogenous hypothalamic GnRH secretion may occur at the midcycle in normal women. This study also provides evidence that the GnRH requirements for normal follicular and luteal phase dynamics may well be greater than those required for generation of a normal midcycle gonadotropin surge and ovulation in women.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/09/20 alle ore 15:54:58