Effect of intranasal administration of norethisterone and progesterone on pituitary and gonadal function in adult male and female bonnet monkeys (Macaca radiata)

The effect of intranasal spray of norethisterone (NET) and progesterone (P) on serum testosterone (T) and total sperm count in adult male bonnet monkeys and the effect of NET spray on the menstrual cycle in female monkeys has been studied. Whereas NET spray resulted in a drastic decrease in serum T levels and sperm count, P spray caused a decrease in total sperm count only. Intranasal spray of NET in adult cycling female monkeys between days 5 and 14 resulted in shortening of the menstrual cycle; this could be ascribed to a decrease in serum follicle-stimulating hormone, luteinizing hormone, 17 beta-estradiol, and P levels. Nasal spray of only solvent in male or female monkeys, however, had no effect on any of the parameters tested.