Transient neonatal-onset hypothyroidism boosts estradiol synthesis in the testis of adult Wistar rat

Mammalian testis is a target organ for thyroid hormones (Jannini et al., 1995; Aruldhas, 2002). Testis is an exocrine organ because it produces sperm and it is also an endocrine organ producing hormones (MendisHandagama, 2012). Histologically, the testis consists of three major cell types: Leydig cell (LCs) (steroidogenic cells), Sertoli cells (SCs) (nursery cells) and germ cells (GCs). LCs lie in cluster or groups near blood vessels in the testicular interstitum (see Saez, 1994), whereas SCs and GCs are confined to the tubular compartment. The hypothalamo-hypophyseal-testicular axis is the primary hormonal regulator of the testis (see Jannini et al., 1995; see Aruldhas, 2002). J Endocrinol Reprod 18 (2014) 1 : 95-110 Original Research