Journal Article Luteinizing Hormone Releasing Hormone (LHRH) in Pituitary Stalk Blood of Rhesus Monkeys: Relationship to Level of LH Release Get access J. D. NEILL, J. D. NEILL 1Department of Physiology and Division of Neurological Surgery, School of Medicine, Emory University Atlanta, Georgia 30322 Search for other works by this author on: Oxford Academic Google Scholar J. M. PATTON, J. M. PATTON 1Department of Physiology and Division of Neurological Surgery, School of Medicine, Emory University Atlanta, Georgia 30322 Search for other works by this author on: Oxford Academic Google Scholar R. A. DAILEY, R. A. DAILEY 1Department of Physiology and Division of Neurological Surgery, School of Medicine, Emory University Atlanta, Georgia 30322 Search for other works by this author on: Oxford Academic Google Scholar R. C. TSOU, R. C. TSOU 1Department of Physiology and Division of Neurological Surgery, School of Medicine, Emory University Atlanta, Georgia 30322 Search for other works by this author on: Oxford Academic Google Scholar G. T. TINDALL G. T. TINDALL 1Department of Physiology and Division of Neurological Surgery, School of Medicine, Emory University Atlanta, Georgia 30322 Search for other works by this author on: Oxford Academic Google Scholar Endocrinology, Volume 101, Issue 2, 1 August 1977, Pages 430–434, https://doi.org/10.1210/endo-101-2-430 Published: 01 August 1977 Article history Received: 14 February 1977 Published: 01 August 1977
PMID 407069 407069 DOI 10.1210/endo-101-2-430 10.1210/endo-101-2-430 Neill et al. 1977, Neill 1977
Cite this article
Neill, J. D., Patton, J. M., Dailey, R. A., Tsou, R. C., & Tindall, G. T. (1977). Luteinizing hormone releasing hormone (LHRH) in pituitary stalk blood of rhesus monkeys: relationship to level of LH release. Endocrinology, 101(2), 430-434. https://doi.org/10.1210/endo-101-2-430
Neill JD, Patton JM, Dailey RA, Tsou RC, Tindall GT. Luteinizing hormone releasing hormone (LHRH) in pituitary stalk blood of rhesus monkeys: relationship to level of LH release. Endocrinology. 1977;101(2):430-434. doi:10.1210/endo-101-2-430
Neill, Jimmy D., et al. "Luteinizing hormone releasing hormone (LHRH) in pituitary stalk blood of rhesus monkeys: relationship to level of LH release." Endocrinology, vol. 101, no. 2, 1977, pp. 430-434.
A push-pull perfusion (PPP) system was used to carry out the first examination of LHRH release from the mediobasal hypothalami (MBH) of conscious, freely moving rats during stages of the estrous (E) cycle and after ovariectomy (Ovx). Female rats received push-pull cannula (PPC) implants into the MBH and then were allowed to recover for 2–10 weeks before PPP experiments. During that time, E cycles were determined by daily inspection of vaginal smears. After exhibiting two consecutive E cycles, rats were fitted with indwelling jugular catheters between 0830–1030 h and subjected to PPP of the MBH and hourly bleeding for more than 6 h. LHRH and LH levels were determined by RIA in perfusates and plasma, respectively. PPP and bleeding sessions were performed on the afternoon of proestrus (Pro; n – 10), diestrous day I (DI; n – 5), diestrous day II (DII; n – 5), estrus (E; n – 5), or more than 28 days after Ovx (n – 5). LHRH output was detectable in at least some samples in all rats whose PPC tips resided within 0.5 mm of the rostrolateral median eminence. Basal LHRH output (<0.2 to 1.2 pg.12 min) appeared to be pulsatile in all groups. During Pro, higher LHRH levels permitted pulse frequency determinations (average Pro interpulse interval, 48.0 min). Overall LHRH output during Pro was elevated (P< 0.01) compared to that in all other groups and was distinctly biphasic; a putative priming pulse (P < 0.05) occurred 2–3 h before the occurrence of a larger main peak (1.6–7.0 pg-12 min) at approximately 1600–1730 h (lights on from 0500–1900 h). Proestrous (Pro) LH levels in rats bearing PPC implants were only 10–30% of those in intact rats regardless of PPP. Nonetheless, these rats did exhibit temporally normal Pro LH surges concident with LHRH release. In DI and DII rats, LHRH pulse amplitude increased moderately for a brief period in the late afternoon (P < 0.01 only when data was normalized to the largest peak). LHRH output in E rats was low and mostly undetectable. Pulse amplitude in ovariectomized (Ovx) rats remained constant and low throughout the afternoon, while LH levels were elevated to typical post-Ovx values. We conclude from this study that (1) a biphasic LHRH surge occurs on the afternoon of Pro which may act to prime and then stimulate pituitary gonadotrophes, (2) small but significant increases in LHRH pulse amplitude occur between 1500–1900 h in DI and DII rats, but not in Ovx or E rats, and (3) LH, but not LHRH, release is increased in Ovx rats, suggesting that the negative feedback effects of ovarian steroids operate primarily at the level of the pituitary gland.
Ovariectomized rhesus monkeys bearing hypothalamic lesions which had abolished endogenous LHRH production, as evidenced by a profound reduction in gonadotropin secretion, but in which LH and FSH secretion was reestablished by a chronic intermittent iv infusion of synthetic LHRH (1 microgram/min for 6 min every hour) were used to investigate the sites of the negative and positive feedback actions of estradiol in the control of gonadotropin secretion. The administration of estradiol to such animals, while continuing the LHRH replacement regimen, resulted in a decline in circulating LH and FSH levels, followed by an unambiguous discharge of these hormones. The time course of this biphasic pattern of gonadotropin secretion was remarkably similar to that observed in response to estradiol administration in otherwise intact ovariectomized animals. These results suggest that, in the rhesus monkey, estradiol can exert both its negative and positive feedback actions on gonadotropin secretion at the level of the pituitary gland.
Brandao BM et al., 2025·Hormones and Behavior·
Open Access
Hormonal contraceptives (HCs) are widely used, yet their effects on emotional and cognitive processes remain poorly understood. This study examined how HC use may influence emotional reactivity, emotion regulation, and emotional memory. Female participants (N = 179), either using HCs (N = 87) or naturally cycling (NC; N = 92), were randomly assigned to one of three groups: no emotion regulation (control), distancing and immersion, or reinterpretation and immersion. The emotion regulation groups completed emotion regulation training in which they viewed emotional images while applying different emotion regulation strategies, followed by a surprise memory test. Overall, HC users showed greater emotional reactivity to emotional images compared to NC participants. Both HC and NC groups successfully applied emotion regulation strategies as measured by changes in emotional affect; however, distancing led to a greater reduction in negative emotions compared to reinterpretation, particularly among HC users. Both HC and NC groups showed better memory for positive images after applying immersion. For negative images, HC users showed reduced memory performance when applying either distancing or reinterpretation, an effect not observed in NC participants. These findings suggest that HC use may influence specific aspects of emotional processing and memory, highlighting the need for more nuanced research on the cognitive and emotional effects of hormonal contraceptives.
Lara HE et al., 2025·Frontiers in endocrinology·
Open Access
Conflict of interest statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision.