Gonadotropin stimulated protein phosphorylation in porcine granulosa cells

Treatment of granulosa cells with luteinizing hormone (LH) or follicle-stimulating hormone (FSH) stimulated the phosphorylation of a 58,000 molecular weight protein found in the 900 x g pellet. The phosphorylation of this protein was rapid, being significant at 1 min. LH treatment for 30 min induced greater phosphorylation of this protein than did FSH. LH and FSH also appeared to stimulate the phosphorylation of different 900 x g pellet proteins. Since both are known to utilize cAMP as a second messenger, the finding of these unique gonadotropin-induced phosphorylations may point to an additional regulatory mechanism.