Prolactin (PRL) is the most versatile and diverse of all the pituitary hormones in its physiological actions in hair growth, sebaceous gland activity and mammary gland alterations in mammals, spermatogenesis and its effects on accessory reproductive glands in males. There are several factors which are involved in the regulation of this hormone. The role of excitatory amino acid (EAA) is very important in the regulation of all the hormones including PRL. EAAs contribute for the regulatory processes through different pathways . This book provides information regarding the contribution of EAA using opioidergic and adrenergic pathways as well as involvement of endogenous EAA to regulate the PRL during different conditions like basal and stimulated. The work was done on nonhuman primate Rhesus monkeys (macaca mulatta). The book will provide a great help for those who wants to study the physiological regulation of PRL in primates