Prepubertal rat thymus secretes a factor that modulates gonadotropin secretion in cultured rat pituitary cells

Thymus development and function are influenced by endocrine glands. On the other hand, the absence of thymus results in endocrine disturbances. The aim of the present paper is to investigate the direct influence of thymus products on the gonadotropin secretion of rat pituitary cells in culture. In this study, a chromatographic fraction obtained from the acetonic powder of thymus from 14-15 day-old rats (TF) increased the GnRH stimulated LH and FSH secretion from cultured pituitary cells, but had no effect on the basal secretion of these gonadotropins. The addition of incubation medium from thymus (TIM) to cultured pituitary cells further enhanced GnRH stimulated FSH and LH production, the effect was dose related. The GnRH potentiating effect of thymus incubation medium was also present in a chromatographic fraction of around 28 Kd obtained from this medium. These data suggest that the prepubertal thymus contains and secretes a factor that modulates pituitary cells secretion potentiating the Gn-RH effect.