Related Experiment Video
Updated: Sep 14, 2025

Hypothalamic Kisspeptin Neurons as a Target for Whole-Cell Patch-Clamp Recordings
Published on: March 17, 2023
VMN growth hormone-releasing hormone receptor regulation of counterregulatory transmission
Subash Sapkota1, Rami Shrestha1, Sushma Katakam1
1School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Rm 356 Bienville Building, 1800 Bienville Drive, Monroe, LA 71201, USA.
Abstract:
Ventromedial hypothalamic nucleus (VMN) growth hormone-releasing hormone (Ghrh) neurotransmission governs counterregulatory hormone release. Recent studies document Ghrh control of hypoglycemia-sensitive counterregulatory neurotransmitter expression in dorsomedial VMN (VMNdm) Ghrh/steroidogenic factor-1 (SF-1) neurons. In this study, Ghrh receptor (Ghrh-R) gene silencing was implemented in vivo to determine if VMN Ghrh-R shapes counterregulation. Intra-VMN Ghrh-R siRNA augmented corticosterone secretion in vehicle or insulin-injected male rats, but this hormone was correspondingly refractory or inhibited in eu- versus hypoglycemic females. In each sex, gene knockdown up- or down-regulated baseline glucagon and growth hormone (GH) release, but hypoglycemia reversed the direction of Ghrh-R control of each hormone. Single-cell laser catapult-microdissected VMNdm Ghrh/SF-1 neuron multiplex qPCR analysis revealed contrary VMN Ghrh-R gene-silencing effects on eu- versus hypoglycemic SF-1 mRNA levels. In both sexes, Ghrh-R siRNA up-regulated mRNAs encoding counterregulation-repressive (γ-aminobutyric acid) or -enhancing (nitric oxide) transmitter protein markers, unrelated to plasma glycemic profiles. Ghrh-R regulation of Ghrh gene transcription was absent (euglycemic) or stimulatory (hypoglycemic) in females, and receptor control of glutaminase mRNA, a marker for the counterregulatory-augmenting neurochemical glutamate, was lost in hypoglycemic males. Ghrh-R gene silencing caused uniform up-regulation of 5'-AMP-activated protein kinase alpha-2 (AMPKα2) mRNA in each sex, independent of glucose status, but caused dissimilar changes in AMPKα1 transcription in eu- versus hypoglycemic females. The outcomes provide novel evidence that VMN Ghrh-R signaling imposes glucose-dependent control of counterregulatory hormone secretion and distinctive VMNdm neuron counterregulatory transmitter marker gene profiles. Data infer that this metabolic control may involve SF-1 (both sexes)- and AMPKα1 (female)-dependent mechanisms.
More Related Videos
09:30Dual Somatic Recordings from Gonadotropin-Releasing Hormone GnRH Neurons Identified by Green Fluorescent Protein GFP in Hypothalamic Slices
Published on: February 23, 2010
11:17Comparative Analysis of Human Growth Hormone in Serum Using SPRi, Nano-SPRi and ELISA Assays
Published on: January 7, 2016
Related Concept Videos
Regulation of Hormone Secretion
Humoral...
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...
Feedback Loops
Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...
Regulation of Food Intake
Hormones of the Pituitary Gland
The most abundantly secreted hormone from the anterior lobe is the growth hormone, which controls overall growth by...