The role of testosterone (T) in the modulation of pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH) sensitivity to DBcAMP was examined in the pituitary monolayer cultures prepared from intact young female rats. Hormone contents in media and cell homogenates were determined by radioimmunoassays. Incubation with 8 and 4 mM DBcAMP for 4 h consistently induced a significant (P less than 0.05) increase in FSH and LH release, respectively. Pretreatment with 10 nM T for 4 days reduced the minimal dose of DBcAMP required to stimulate FSH release (2 vs. 8 mM) but had no effect on the DBcAMP-induced LH release. Data indicate that T treatment for 4 or 7 days stimulated total FSH contents (sum of hormone contents in medium and cells). Similarly, incubation with 10 mM DBcAMP for 4 h significantly increased total FSH content per dish in both the T-treated and non-T-treated cultures. Neither T nor DBcAMP had any effect on LH production under these conditions. Intracellular cAMP was significantly increased to three- to eightfold of control after T treatment for 3 or 6 h, respectively. Furthermore, cAMP-binding activities were significantly increased after T treatment for 1 or 4 days (174 or 422% of control). Our previous data indicate that estrogen increases LH production, cAMP binding, cAMP production, and LH sensitivity to DBcAMP, and these data indicate that T exerts stimulatory effects on FSH in a similar fashion. These results support the concept that the two gonadotropins are regulated independently via different gonadal steroids.