Related Experiment Video
Updated: Jun 22, 2026

An In Vivo Estrogen Deficiency Mouse Model for Screening Exogenous Estrogen Treatments of Cardiovascular Dysfunction After Menopause
Published on: August 13, 2019
Complexities of adjuvant endocrine therapy in young premenopausal women
N Lynn Henry1, Jennifer J Griggs
1Division of Hematology/Oncology, Department of Internal Medicine, University of Michigan, Medical School, Ann Arbor, Michigan, USA.
Abstract:
Overall, this excellent overview of management issues for breast cancer patients under 40 years of age highlights the major questions surrounding choices of adjuvant systemic therapy. Treatment choices are dependent on breast cancer biology (receptor status) as well as patient factors (ovarian function and desire for future fertility). As many unanswered questions remain, it is important to continue to enroll subjects in clinical trials focused on this important patient population.
Related Concept Videos
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...
Hormonal Regulation of the Menstrual Cycle
At puberty, GnRH begins a pulsatile release pattern, which triggers the anterior pituitary gland to secrete follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The frequency and amplitude of GnRH pulses vary across the menstrual cycle, with faster pulses favoring LH release and slower pulses favoring FSH release.
Endocrine Signaling
Endocrine Signaling
Target Cell Response to Hormones
Notably, the cellular response can be regulated by altering the number of receptors expressed in the cell. For example, prolonged exposure to elevated hormone levels results in a gradual decline or down-regulation in the number of receptors for that specific hormone on the cell surface. Conversely, in response to low hormone levels, cells may use up-regulation, producing an...
Menopause