. Author manuscript; available in PMC: 2019 Aug 5.

Published in final edited form as: Neurobiol Dis. 2014 May 27;72(Pt B):153–166. doi: 10.1016/j.nbd.2014.05.021

Table 1.

Developmental stages in rats, based on hypothalamus-pituitary-gonadal maturation

Stage	Females		Males
	PN	Features	PN	Features
Neonatal	0–6		0–6
Infantile	7–21		7–21
Juvenile	21–32		21–35
Early pubertal	32–36	Anestrus to early proestrus; pulsatile gonadotropin release in sleep only	35–45	Pulsatile gonadotropin release in sleep only
Puberty	34–38	1^st proestrus, first estrus; 1^st surge of gonadotropins and vaginal opening	45–60	Gonadotropin release also in wakefulness; Maximal testicular response to gonadotropins; Increase in Leydig cells and steroidogenesis
Adult	>60		>60

The table is based on reference (Ojeda et al., 1980). Please note that these age groups have been defined based on the endocrine changes occurring during maturation and not brain maturation. In general, PN8–10 rats are considered equivalent to full-term newborn humans, based on gross brain growth and its DNA, cholesterol and water contents that resemble those of a human full-term neonate (Dobbing and Sands, 1979; Gottlieb et al., 1977).