Elevation of Plasma Gonadotropin Concentration in Response to Mammalian Gonadotropin Releasing Hormone (Grh) Treatment of the Male Brown Trout as Determined by Radioimmunoassay

Abstract

Rapid increase of the plasma gonadotropin concentration as measured by radioimmunoassay has been demonstrated in response to GRH treatment of the sexually mature male brown trout. Peak gonadotropin values were observed within 15 minutes of GRH treatment, however, the return to baseline values was prolonged compared with the mammalian response. These data support the concept that the brain, operating via releasing hormones, plays a role in the control of pituitary hormone secretion in fish.