Differences in serum steroid hormones concentrations in Spontaneously Hypertensive Rats (SHR) – an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD)

Abstract

Spontaneously hypertensive rats are the most common animal model used to study attention deficit hyperactivity disorder (ADHD). The present study investigated the levels of steroid hormones in the bloodstream of hypertensive rats and its normotensive control strain, Wistar-Kyoto rats, to check if there are any hormonal differences between both strains at the onset of ADHD. Plasma samples were collected from young (5-week-old) and mature (10-week-old) male hypertensive and normotensive rats to determine the serum level of testosterone, 17beta-estradiol, free estriol, progesterone, corticosterone and cortisol using ELISA kits. The results showed statistically significant increases in serum levels of testosterone and free estriol in 10-week-old hypertensive and normotensive rats when compared to 5-week-old animals. Moreover, the concentrations of progesterone, corticosterone and cortisol were significantly elevated in 10-week-old hypertensive rats when compared to 5-week-old animals of both strains as well as 10-week-old normotensive rats. Hormonal differences observed between 10-week-old hypertensive and normotensive rats were also accompanied by differences in the volumes of lateral ventricles as well as the third ventricle and cerebral aqueduct. In conclusion, elevated contents of progesterone, corticosterone and cortisol in hypertensive rats may be associated not only with ADHD but also with developing hypertension. This question needs further study.

Prenatal Exposure to High Cortisol Induces ADHD-like Behaviors with Delay in Spatial Cognitive Functions during the Post-weaning Period in Rats

“…3~6). These behavioral phenotypes are clearly consistent with hyperactivity in ADHD models [19,23]. It is also possible that increased spent time and distance in the center of the OF test and the open arms of the EPM test reflect anxiolytic and impulsive emotion of Corti.…”

“…Recently, it was reported that prenatal stress increases anxiety, depression, and stress-related hyperactive behaviors as well as deficits in learning and memory function [15][16][17][18]. Particularly, spontaneously hypertensive rats (SHRs), which are frequently used in studies of attention deficit hyperactivity disorder (ADHD), showed higher serum levels of progesterone, corticosterone and cortisol than normal rats, suggesting that the endocrine-dependent regulation in developmental nervous system plays a major role in determining behavioral and emotional disorders [19]. However, although neuroendocrine dysregulation has been targeted in studies of psychiatric disorders, it is still necessary to investigate whether maternal stressors during pregnancy directly mediates behavioral and emotional abnormalities in postpartum offspring.…”

Age- and Hypertension-Related Changes in NOS/NO/sGC-Derived Vasoactive Control of Rat Thoracic Aortae

“…In SHRs, an enhanced lipolysis has been suggested as a result of increased sympathetic outflow; moreover, an increased secretion of cholesterol combined with deficiencies in enteric capture and molecular transport of cholesterol was also demonstrated [ 20 , 21 ]. In addition, it has been shown that the levels of cholesterol-related steroid hormones, such as corticosterone, were elevated already in 7-week-old female SHRs compared to age-matched WKYs, and in 10-week-old SHRs, the serum levels of progesterone, corticosterone, and cortisol were significantly elevated compared to those in 5-week-old SHRs and 10-week-old WKYs [ 16 , 22 ], which may also contribute to the reduction in total cholesterol in our experimental group.…”

Network pharmacology, molecular docking, and experimental validation to explore the potential mechanism of Long Mu Qing Xin mixture for the treatment of attention deficit hyperactivity disorder

“…SHR is considered a commonly used and well-studied animal model of ADHD because it exhibits behavioral disorders similar to ADHD in terms of hyperactivity, impulsivity, and learning disabilities, predicts molecular genetics and neuropathological mechanisms associated with ADHD, and responds to first-line ADHD therapeutic agents (Rahi and Kumar, 2021). Since ADHD is more common in boys than in girls, and male rats are superior to females in terms of surface validity (hyperactive/ impulsive behavior), male SHRs are more suitable as an animal model of ADHD (Bayless et al, 2015;Kozłowska et al, 2019). This study attempted to use male SHRs as the ADHD animal model and WKY rats as the normal control to investigate the potential mechanisms of LMQXM for ADHD and explore the effects of LMQXM on behavioral performance and related factors in SHRs.…”