Danmei Li
University of California, San Diego
Internal medicineEndocrinologyGene knockdownChemistryGonadotropic cellStimulationGrowth factorProteaseGranulosa cellGonadotropinGonadotropin-releasing hormoneAgonistAnterior pituitaryFollicle-stimulating hormoneInsulin-like growth factor-binding proteinOvarian follicleInsulin-like growth factorGonadotropin secretionHormoneBiologyCell biology
12Publications
7H-index
507Citations
Publications 12
Newest
#1Taeshin Kim (UCSD: University of California, San Diego)H-Index: 7
#2Danmei Li (UCSD: University of California, San Diego)H-Index: 7
Last. Mark A. Lawson (UCSD: University of California, San Diego)H-Index: 25
view all 7 authors...
: A defining characteristic of the hypothalamus-pituitary-gonad reproductive endocrine axis is the episodic secretion of the pituitary gonadotropin hormones LH and FSH by the anterior pituitary gonadotropes. Hormone secretion is dictated by pulsatile stimulation, with GnRH released by hypothalamic neurons that bind and activate the G protein-coupled GnRH receptor expressed by gonadotropes. Hormone secretion and synthesis of gonadotropins are influenced by the amplitude and frequency of GnRH stim...
5 CitationsSource
#1Tomohiro Terasaka (UCSD: University of California, San Diego)H-Index: 10
#2Taeshin Kim (UCSD: University of California, San Diego)H-Index: 7
Last. Mark A. Lawson (UCSD: University of California, San Diego)H-Index: 25
view all 9 authors...
: Gonadotropin secretion, which is elicited by GnRH stimulation of the anterior pituitary gonadotropes, is a critical feature of reproductive control and the maintenance of fertility. In addition, activation of the GnRH receptor (GnRHR) regulates transcription and translation of multiple factors that regulate the signaling response and synthesis of gonadotropins. GnRH stimulation results in a broad redistribution of mRNA between active and inactive polyribosomes within the cell, but the mechanis...
5 CitationsSource
#1Song Li (UCSD: University of California, San Diego)H-Index: 2
#2Ekaette F. Mbong (UCSD: University of California, San Diego)H-Index: 4
Last. Mark A. Lawson (UCSD: University of California, San Diego)H-Index: 25
view all 6 authors...
: An emerging body of evidence supports the concept that the pituitary is a site for integration of multiple physiological and metabolic signals that inform and modulate endocrine pathways. Multiple endocrine mediators of energy balance and adiposity are known to impinge on the neuroendocrine axis regulating reproduction. Observations in humans show that obesity is correlated with decreased gonadotropin secretion, and studies have also suggested that pituitary sensitivity to stimulation by gonad...
7 CitationsSource
#1Tomohiro Terasaka (UCSD: University of California, San Diego)H-Index: 10
#2Mary E. Adakama (UCSD: University of California, San Diego)H-Index: 1
Last. Mark A. Lawson (UCSD: University of California, San Diego)H-Index: 25
view all 7 authors...
Biological rhythms lie at the center of regulatory schemes that control many aspects of living systems. At the cellular level, meaningful responses to external stimuli depend on propagation and quenching of a signal to maintain vigilance for subsequent stimulation or changes that serve to shape and modulate the response. The hypothalamus-pituitary-gonad endocrine axis that controls reproductive development and function relies on control through rhythmic stimulation. Central to this axis is the p...
7 CitationsSource
#1Sha LiuH-Index: 8
Last. Mark D. LeibowitzH-Index: 19
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The retinoid X receptor (RXR) agonist bexarotene can cause clinically significant hypothyroidism in cutaneous T cell lymphoma patients. The mechanism by which the RXR agonist produces this effect is unclear. We have studied the impact of a selective RXR agonist (rexinoid), LG100268, on rat thyroid axis hormones and show that the acute phase of hypothyroidism is associated with reduced pituitary TSH secretion. A single oral administration of LG100268 to naive Sprague Dawley rats causes a rapid an...
91 CitationsSource
#1Shunichi Shimasaki (UCSD: University of California, San Diego)H-Index: 79
#2R. J. ZachowH-Index: 1
Last. Gregory F. EricksonH-Index: 66
view all 9 authors...
Bone morphogenetic proteins (BMPs) comprise a large group of polypeptides in the transforming growth factor β superfamily with essential physiological functions in morphogenesis and organogenesis in both vertebrates and invertebrates. At present, the role of BMPs in the reproductive system of any species is poorly understood. Here, we have established the existence of a functional BMP system in the ovary, replete with ligand, receptor, and novel cellular functions. In situ hybridization histoche...
286 CitationsSource
#1Toshihide KuboH-Index: 2
#2Shunichi ShimasakiH-Index: 79
Last. Gregory F. EricksonH-Index: 66
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Inhibin-α subunit (Inh-α) gene expression is important for granulosa cell (GC) differentiation and prevention of ovarian tumorigenesis. Studies on Inh-α regulation have implicated activin and insulin-like growth factor-I (IGF-I) in the mechanisms of expression. Here we present evidence that endogenously produced IGF-I plays an obligatory role in activin-induced Inh-α production. Primary cultures of rat GC were incubated with increasing concentrations of various regulatory molecules, and the leve...
11 CitationsSource
#1Danmei LiH-Index: 7
#2Toshihide KuboH-Index: 2
Last. Gregory F. EricksonH-Index: 66
view all 5 authors...
Insulin-like growth factor-I (IGF-I) is essential for FSH-dependent steroidogenesis by rat granulosa cells (GC), but whether IGF-I is required for other FSH-dependent functions is unknown. To investigate the role of IGF-I in the mechanisms of FSH-stimulated inhibin ca-subunit (Inh-ca) production, rat GC were cultured with FSH, IGF-I, insulin-like growth factor-binding protein (IGFBP)-4, IGFBP-5, and/or anti-IGF-I antibody. Inh-a protein and mRNA levels were measured in conditioned medium and cel...
23 CitationsSource
#1Francesc Piferrer (UCSD: University of California, San Diego)H-Index: 57
#2Danmei Li (UCSD: University of California, San Diego)H-Index: 7
Last. Gregory F. Erickson (UCSD: University of California, San Diego)H-Index: 66
view all 4 authors...
Abstract The ability of TGF-α to regulate insulin-like growth factor binding protein-4 (IGFBP-4), was investigated. Primary cultures of rat granulosa cells (GC) were grown in serum-free medium with rat (r) TGF-α and/or rFSH, and secreted IGFBP-4 protein and its steady state mRNA levels were measured by Western immunoblotting and Northern blotting, respectively. Control (untreated) cells secreted IGFBP-4 spontaneously, and the levels were increased by rTGF-α in a dose- and time-dependent manner. ...
13 CitationsSource
#1Gregory F. Erickson (UCSD: University of California, San Diego)H-Index: 66
#2Danmei Li (UCSD: University of California, San Diego)H-Index: 7
Last. Denis A. Magoffin (UCLA: University of California, Los Angeles)H-Index: 43
view all 6 authors...
There has been considerable interest in rat ovarian insulin-like growth factor binding proteins IGFBPs because they are potent inhibitors of FSH action.In situ, IGFBP-2 and −4 and IGFBP-3 mRNAs are expressed in rat theca interstitial (TIC) and theca lutein cells respectively. Although much is known about IGFBPs in rat TIC at the mRNA level, the synthesis and regulation of IGFBP proteins remain poorly understood. The purpose of this study was to identify the species of IGFBPs produced by TIC and ...
5 CitationsSource