Sex-dimorphic growth hormone-releasing hormone (Ghrh) receptor regulation of ventromedial hypothalamic nucleus Ghrh neuron estrogen receptor variant gene expression
Year: 2025
Type: article
Abstract: Estradiol shapes systemic glucose homeostasis by action on ventromedial hypothalamic nucleus (VMN) targets. The neuropeptide transmitter growth hormone-releasing hormone (Ghrh) governs counterregulatory neurochemical marker mRNA expression in dorsomedial VMN (VMNdm) Ghrh/steroidogenic factor-1 (SF-1/Nr5a1) neurons. The current research used tools for in vivo gene silencing and single-cell laser catapult microdissection/multiplex qPCR to determine if VMN Ghrh receptor (Ghrh-R) regulates nuclear and/or membrane estrogen receptor (ER) gene transcription in those neurons. Intra-VMN Ghrh-R siRNA correspondingly up- or down-regulated baseline VMNdm Ghrh/SF-1 neuron ER-alpha (ERα) or G protein-coupled estrogen receptor-1 (GPER) transcripts in male rats; neither mRNA was affected by gene silencing in females. In each sex, hypoglycemic repression of these ER gene profiles was averted by Ghrh-R gene knockdown. Both sexes exhibited diminished baseline VMNdm Ghrh/SF-1 neuron ER-beta (ERβ) gene expression following Ghrh-R gene knockdown. ERβ mRNA was diminished (male) or unaffected (female) by hypoglycemia; Ghrh-R siRNA pretreatment enhanced transcript levels in hypoglycemic rats of either sex. Aromatase gene expression is higher in male versus female VMNdm Ghrh/SF-1 neurons and is inhibited by hypoglycemia in male rats alone. Ghrh-R gene knockdown augmented aromatase mRNA levels in each sex irrespective of glucose status. Results document glucose-dependent Ghrh-R control of VMNdm Ghrh/SF-1 neuron ERα (female), ERβ (both sexes), and GPER (both sexes) gene expression. Ongoing studies aim to characterize mechanisms that cause a hypoglycemia-associated gain of regulatory control or switch in direction (stimulatory-to-inhibitory) of control. Outcomes identify VMNdm Ghrh/SF-1 neurons as a putative neuroestradiol source in each sex and implicate Ghrh-R in hypoglycemic repression of this neurosteroid profile in males.
Source: Translational Neuroscience
Authors: Subash Sapkota, Karen P. Briski
Institution: University of Louisiana at Monroe
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $1,808
OpenAlex ID: W4411349378