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Midcycle levels of sex steroids are sufficient to recreate the follicle-stimulating hormone but not the luteinizing hormone midcycle surge: evidence for the contribution of other ovarian factors to the surge in normal women.
J Clin Endocrinol Metab. 1995 May; 80(5):1541-7.JC

Abstract

The midcycle surge of LH and FSH is critical for final oocyte maturation and ovulation. In normal women, this gonadotropin surge follows a gradual increase in estradiol levels (E) and is concomitant with a small increase in progesterone (P) levels. However, whether sex steroids alone are sufficient to induce the complex neuroendocrine interactions underlying this switch from negative to positive feedback is unknown. In this study, physiological midcycle levels of E, with and without periovulatory levels of P (E+P and E, respectively) were infused into 18 normally cycling women in their early to midfollicular phases. The resulting sex-steroid-induced gonadotropin responses were then compared with 118 spontaneous midcycle surges in 81 normal women. The sex steroid levels achieved by the infusions were within the normal ranges for the spontaneous midcycle surge. However, neither women who received E alone nor those who received E+P had LH responses that achieved those of spontaneous LH surges in the normal menstrual cycle (NMC) [82.7 +/- 16.23 IU/L E (mean +/- SEM), 69.7 +/- 12.01 IU/L E+P vs. 121.7 +/- 6.23 IU/L NMC, P < 0.05 E and P < 0.005 E+P vs. NMC]. In contrast, peak FSH levels evoked by E and P matched the spontaneous FSH peaks (19.0 +/- 2.1 IU/L E, 24.5 +/- 4.0 IU/L E+P vs. 23.3 +/- 0.9 IU/L NMC, P = 0.07 E and P = 0.71 E+P vs. NMC). In conclusion, sex steroids alone do not seem to be sufficient to stimulate the normal midcycle LH surge. We hypothesize that other ovarian factors, which are missing in the midfollicular phase, are required for the generation of the normal midcycle surge of LH.

Authors+Show Affiliations

Reproductive Endocrine Unit, Massachusetts General Hospital, Boston 02114, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7744998

Citation

Taylor, A E., et al. "Midcycle Levels of Sex Steroids Are Sufficient to Recreate the Follicle-stimulating Hormone but Not the Luteinizing Hormone Midcycle Surge: Evidence for the Contribution of Other Ovarian Factors to the Surge in Normal Women." The Journal of Clinical Endocrinology and Metabolism, vol. 80, no. 5, 1995, pp. 1541-7.
Taylor AE, Whitney H, Hall JE, et al. Midcycle levels of sex steroids are sufficient to recreate the follicle-stimulating hormone but not the luteinizing hormone midcycle surge: evidence for the contribution of other ovarian factors to the surge in normal women. J Clin Endocrinol Metab. 1995;80(5):1541-7.
Taylor, A. E., Whitney, H., Hall, J. E., Martin, K., & Crowley, W. F. (1995). Midcycle levels of sex steroids are sufficient to recreate the follicle-stimulating hormone but not the luteinizing hormone midcycle surge: evidence for the contribution of other ovarian factors to the surge in normal women. The Journal of Clinical Endocrinology and Metabolism, 80(5), 1541-7.
Taylor AE, et al. Midcycle Levels of Sex Steroids Are Sufficient to Recreate the Follicle-stimulating Hormone but Not the Luteinizing Hormone Midcycle Surge: Evidence for the Contribution of Other Ovarian Factors to the Surge in Normal Women. J Clin Endocrinol Metab. 1995;80(5):1541-7. PubMed PMID: 7744998.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Midcycle levels of sex steroids are sufficient to recreate the follicle-stimulating hormone but not the luteinizing hormone midcycle surge: evidence for the contribution of other ovarian factors to the surge in normal women. AU - Taylor,A E, AU - Whitney,H, AU - Hall,J E, AU - Martin,K, AU - Crowley,W F,Jr PY - 1995/5/1/pubmed PY - 2001/3/28/medline PY - 1995/5/1/entrez SP - 1541 EP - 7 JF - The Journal of clinical endocrinology and metabolism JO - J Clin Endocrinol Metab VL - 80 IS - 5 N2 - The midcycle surge of LH and FSH is critical for final oocyte maturation and ovulation. In normal women, this gonadotropin surge follows a gradual increase in estradiol levels (E) and is concomitant with a small increase in progesterone (P) levels. However, whether sex steroids alone are sufficient to induce the complex neuroendocrine interactions underlying this switch from negative to positive feedback is unknown. In this study, physiological midcycle levels of E, with and without periovulatory levels of P (E+P and E, respectively) were infused into 18 normally cycling women in their early to midfollicular phases. The resulting sex-steroid-induced gonadotropin responses were then compared with 118 spontaneous midcycle surges in 81 normal women. The sex steroid levels achieved by the infusions were within the normal ranges for the spontaneous midcycle surge. However, neither women who received E alone nor those who received E+P had LH responses that achieved those of spontaneous LH surges in the normal menstrual cycle (NMC) [82.7 +/- 16.23 IU/L E (mean +/- SEM), 69.7 +/- 12.01 IU/L E+P vs. 121.7 +/- 6.23 IU/L NMC, P < 0.05 E and P < 0.005 E+P vs. NMC]. In contrast, peak FSH levels evoked by E and P matched the spontaneous FSH peaks (19.0 +/- 2.1 IU/L E, 24.5 +/- 4.0 IU/L E+P vs. 23.3 +/- 0.9 IU/L NMC, P = 0.07 E and P = 0.71 E+P vs. NMC). In conclusion, sex steroids alone do not seem to be sufficient to stimulate the normal midcycle LH surge. We hypothesize that other ovarian factors, which are missing in the midfollicular phase, are required for the generation of the normal midcycle surge of LH. SN - 0021-972X UR - https://www.unboundmedicine.com/medline/citation/7744998/Midcycle_levels_of_sex_steroids_are_sufficient_to_recreate_the_follicle_stimulating_hormone_but_not_the_luteinizing_hormone_midcycle_surge:_evidence_for_the_contribution_of_other_ovarian_factors_to_the_surge_in_normal_women_ L2 - https://academic.oup.com/jcem/article-lookup/doi/10.1210/jcem.80.5.7744998 DB - PRIME DP - Unbound Medicine ER -