Pituitary-testicular axis dysfunction in methimazole-induced hypothyroidism in rats

Abstract

Introduction: Thyroid hormones play a major role in the regulation of testicular maturation and growth and in the control of Sertoli and Leydig cell functions in adulthood. When naturally occurring, hypothyroidism causes male hypogonadotropic hypogonadism and Sertoli cell function disorders, but when iatrogenic and methimazole-induced its influence on the pituitary-testicular axis function with respect to Sertoli cells is poorly known. Material and Methods: Male adult Wistar rats (n = 14) were divided into two groups: E – taking methimazole orally for 60 days, and C – control animals. After 60 d, the concentrations in serum of testosterone, follicle-stimulating and luteinising hormones, and inhibins A and B were measured. Testicles were examined morphologically: the apoptotic Sertoli cell percentage (ASC%) and number of these cells functional per tubular mm2 (FSCN/Tmm2) were calculated. Results: In group E, inhibin A was higher while inhibin B was lower than in group C. ASC% was higher and FSCN/Tmm2 lower in group E than in group C. Conclusion: A specific modulation of Sertoli cell function in the course of methimazole-induced hypothyroidism leads to a simultaneous concentration increase in inhibin A and decrease in B. Inhibin A might share responsibility for pituitary-testicular axis dysfunction and hypogonadotropic hypogonadism in this model of hypothyroidism.

Kisspeptin treatment reverses high prolactin levels and improves gonadal function in hypothyroid male rats

“…When we evaluated the expression of key enzymes in the steroidogenic cascade, hypothyroidism reduced testicular Star and Cyp11a1 expression . This explains the lower testosterone levels observed in these animals, which has also been demonstrated in other studies 38 , 43 , 46 . While Kp10 treatment did not reestablish the change in Star and Cyp11a1 expression caused by hypothyroidism, it increased nuclear receptor subfamily 5 group A member 1 ( Nr5a1 ), also named steroidogenic factor 1, which is an important transcription factor for testicular steroidogenesis 47 .…”

Selenium protects against nesfatin‐1 modulation of the hypothalamic‐pituitary‐testicular axis during hypothyroidism in male rats

“…In men, hypothyroidism can lead to hypogonadotropic hypogonadism due to an impact on the pituitary‐testicular axis, as it diminishes the levels of gonadotropin and testosterone hormones (Donnelly et al., 2013 ). Despite this, there have been limited studies exploring the mechanism of pituitary‐testicular axis imbalance present (Gołyński et al., 2019 ).…”