Ziram Delays Pubertal Development of Rat Leydig Cells

Ziram [zinc, bis (dimethyldithiocarbamate)] is an agricultural dithiocarbamate fungicide. By virtual screening, we have identified that ziram is a potential endocrine disruptor. To investigate its effects on pubertal development of Leydig cells, 35-day-old male Sprague Dawley rats orally received ziram (2 or 4 mg/kg/d) for 4 weeks and immature Leydig cells isolated from 35-day-old rat testes were treated with ziram (0.5-50 μM in vitro). Serum hormones, Leydig cell number and specific gene or protein expression levels after in vivo treatment were determined and medium androgen levels were measured as well as apoptosis of Leydig cells after in vitro treatment were determined. In vivo exposure to ziram lowered testosterone and follicle-stimulating hormone levels, and reduced Leydig cell number, and downregulated Leydig cell specific gene or protein expression levels. Ziram exposure in vitro inhibited androgen production and steroidogenic enzyme activities in Leydig cells by downregulating expression levels of P450 cholesterol side cleavage enzyme (Cyp11a1), 3β-hydroxysteroid dehydrogenase 1 (Hsd3b1), 17α-hydroxylase/17,20-lyase (Cyp17a1), and 17β-hydroxysteroid dehydrogenase 3 (Hsd17b3) via downregulating the steroidogenic factor 1 (Nr5a1) at a concentration as low as 5 μM. In conclusion, ziram exposure disrupts Leydig cell development during puberty possibly via downregulating Nr5a1.