Involvement of a cholinergic mechanism in the mediation of hippocampal influences on female sexual maturation and somatic development.

Female Wistar rats were bilaterally lesioned in the anterior part of the ventral hippocampus (VHPC) at 21, 26 or 32 days of age. Irrespective of the age at lesioning a significant delay of vaginal opening and of the first ovulation was recorded. This delay of the onset of puberty was consistently associated with a retardation of the body weight increase. Both the puberty-delaying and growth-retarding effects of VHPC lesions produced on day 21 could be prevented by daily s.c. injections of 50 micrograms/100 g b.w. pyridostigmine from day 21 till vaginal opening, but not by the administration of 2 mg/100 g/day pargyline. The findings suggest a cholinergic mediation of stimulatory effects exerted by the hippocampus on sexual maturation and somatic development.