| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, California 92093
Correspondence to S. C. C. Yen.
Submaximal doses of LRF, administered over a period of several hours, either by repeated pulses (10 µg at 2 h intervals x 5) or by constant infusion (0.2 µg/min x 4 h), have permitted the assessment of changes in the releasable gonadotropin during the menstrual cycle. Quantitations in the acute releasable and ultimately releasable gonadotropins were made which represent, respectively, the sensitivity and reserve of the gonadotrophs. The functional expression of these two components of gonadotropin release exhibited profound changes during the menstrual cycle and were in synchrony with the cyclicity of ovarian steroid levels; during the early follicular phase, both sensitivity and reserve were at a minimum, but with increasing levels of E2, a preferential increase in reserve over sensitivity (P < 0.005) was found. Although both sensitivity and reserve increased dramatically near the midcycle, the relative change in these two components was reversed from the late follicular phase to the midcycle surge. The presence of this phenomenon may be causally related to the development of a self-priming effect of LRF at this time, as evidenced by an augmentation of gonadotropin release to the 2nd pulse of LRF. Thus, a build-up in pituitary store consequent to the greater increase in reserve than in sensitivity, together with the appearance of the self-priming effect of LRF induced by progressively rising levels of E2, may constitute the essential dynamics required for the development of the midcycle gonadotropin surge. Pituitary sensitivity and reserve continued to be high during the early luteal phase but reduced progressively thereafter. In all studies, FSH responses were less obvious but showed remarkable parallelism to the pattern of LH responses. We have concluded that the functional capacity of the gonadotrophs exhibits a remarkable cyclic change and that the adenohypophysis represents a critical feedback site in the development of pre-ovulatory gonadotropin surge.
Presented in part at the Annual Meeting of The Endocrine Society, New York, June, 1975. Research supported by Rockefeller Foundation Grant RF 75029.
1 Present Address: Department of Obstetrics and Gynecology, New York Hospital, Cornell Medical Center, 68th Street, New York, New York 10021.
2 Present Address: San Diego Zoo, P.O. Box 551, San Diego, California 92112.
Received September 8, 1975.
This article has been cited by other articles:
 |
|
 |
|
  W. E. Ottowitz, D. D. Dougherty, A. J. Fischman, and J. E. Hall [18F]2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography Demonstration of Estrogen Negative and Positive Feedback on Luteinizing Hormone Secretion in Women J. Clin. Endocrinol. Metab., August 1, 2008; 93(8): 3208 - 3214. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. E. Messinis Ovarian feedback, mechanism of action and possible clinical implications Hum. Reprod. Update, September 1, 2006; 12(5): 557 - 571. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Dafopoulos, C.G. Kotsovassilis, S. Milingos, A. Kallitsaris, G. Galazios, E. Zintzaras, P. Sotiros, and I.E. Messinis Changes in pituitary sensitivity to GnRH in estrogen-treated post-menopausal women: evidence that gonadotrophin surge attenuating factor plays a physiological role Hum. Reprod., September 1, 2004; 19(9): 1985 - 1992. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Nicholls, B. L. Lasley, S. T. Nakajima, K. D. R. Setchell, and B. O. Schneeman Effects of Soy Consumption on Gonadotropin Secretion and Acute Pituitary Responses to Gonadotropin-Releasing Hormone in Women J. Nutr., April 1, 2002; 132(4): 708 - 714. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. E. Messinis, S. Milingos, E. Alexandris, I. Mademtzis, G. Kollios, and K. Seferiadis Evidence of differential control of FSH and LH responses to GnRH by ovarian steroids in the luteal phase of the cycle Hum. Reprod., February 1, 2002; 17(2): 299 - 303. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Zarinan, A. Olivares, D. Soderlund, J.P. Mendez, and A. Ulloa-Aguirre Changes in the biological:immunological ratio of basal and GnRH-releasable FSH during the follicular, pre-ovulatory and luteal phases of the human menstrual cycle Hum. Reprod., August 1, 2001; 16(8): 1611 - 1618. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.H. Nilsson, M. Kaleva, H. Virtanen, A.M. Haavisto, K. Pettersson, and I.T. Huhtaniemi Disparate response of wild-type and variant forms of LH to GnRH stimulation in individuals heterozygous for the LH{beta} variant allele Hum. Reprod., February 1, 2001; 16(2): 230 - 235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Castro-Fernández, A. Olivares, D. Söderlund, J. C. López-Alvarenga, E. Zambrano, J. D. Veldhuis, A. Ulloa-Aguirre, and J. P. Méndez A Preponderance of Circulating Basic Isoforms Is Associated with Decreased Plasma Half-Life and Biological to Immunological Ratio of Gonadotropin-Releasing Hormone-Releasable Luteinizing Hormone in Obese Men J. Clin. Endocrinol. Metab., December 1, 2000; 85(12): 4603 - 4610. [Abstract] [Full Text]
|
|
|
|
|
|
J. L. Sharpless, J. G. Supko, K. A. Martin, and J. E. Hall Disappearance of Endogenous Luteinizing Hormone Is Prolonged in Postmenopausal Women J. Clin. Endocrinol. Metab., February 1, 1999; 84(2): 688 - 694. [Abstract] [Full Text]
|
|
|
|
|
|
P. P. Feuillan, J. V. Jones, K. Barnes, K. Oerter-Klein, and G. B. Cutler Jr. Reproductive Axis after Discontinuation of Gonadotropin-Releasing Hormone Analog Treatment of Girls with Precocious Puberty: Long Term Follow-Up Comparing Girls with Hypothalamic Hamartoma to Those with Idiopathic Precocious Puberty J. Clin. Endocrinol. Metab., January 1, 1999; 84(1): 44 - 49. [Abstract] [Full Text]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
