Related Experiment Video
Updated: May 3, 2026
Experimental Approach to Examine Leptin Signaling in the Carotid Bodies and its Effects on Control of Breathing
Published on: October 25, 2019
Orexin A-mediated stimulation of 3β-HSD expression and testosterone production through MAPK signaling pathways in
Background:
Orexin A (ORA) regulates food intake, energy metabolism, gastrointestinal and reproductive functions.
Aim:
The purpose of this study was to demonstrate whether the expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) and testosterone was stimulated by ORA and mediated through mitogen-activated protein kinases (MAPK) in rat Leydig cells.
Methods:
Primary Leydig cells were isolated from male rat testes, cultured, and treated with ORA under various conditions.
Results:
Orexin receptor 1 (OX (1) R) mRNA, but not orexin receptor 2 mRNA, was detected in primary Leydig cells. ORA up-regulated the expression of OX( 1) R mRNA and protein in a dose-responsive manner and increased the phosphorylation of extracellular receptor kinase 1/2 (ERK1/2) and p38 MAPK levels, but did not affect the phosphorylation of the JNK MAPK. Phosphorylation of ERK1/2 and p38 MAPKs by ORA was blocked with U0126 and SB203580 inhibitors, respectively. An OX(1)R-specific inhibitor, SB334867, also blocked the phosphorylation of ERK1/2 and p38 by ORA. Inhibitor treatment also blocked 3β-HSD expression and testosterone production.
Conclusions:
These results demonstrate that ORA activation of OX(1)R up-regulates 3β-HSD expression and testosterone production via the ERK1/2 and p38 MAPKs signaling pathways in primary rat Leydig cells.
Related Concept Videos
01:26Testosterone: Functions and Regulation
01:22Target 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...
01:19Regulation of Hormone Secretion
Humoral...