Endocrine Abstracts

Hypoglycemia result in significant activation of various neuroendocrine pathways involved in producing peripheral hormonal and metabolic responses aimed at restoring euglycemia. The present study was designed to investigate the involvement of excitatory amino acid neurotransmitter’s (EAA) pathway in the regulation of basal as well as physiologically stimulated PRL secretion in primates. Four adult male Rhesus monkeys (Macaca mulata) were used in the study. Four sets of experiment were performed. In each experiment all the four animals were bled for a period of 3 h (−60–120 min) at 15 min interval. In first three sets of experiments at 0 min, saline (5 ml/animal), Mk-801 (0.1 mg/kg, BW dissolved in 5 ml saline) and insulin (1.0 u/kg=25 ul/kg) injections were given. While in the fourth set of experiment the animals were administered an injection of insulin (bolus) immediately following by an injection of MK-801. Plasma levels of PRL were determined in duplicate using enzyme immunoassay (EIA). Results showed that saline infusion caused no significant change in basal plasma PRL concentrations. Administration of MK-801 decreased plasma PRL concentrations significantly (P<0.001) over the basal levels. Insulin treatment increased plasma PRL secretion significantly when given alone (P<0.05) as well in combination (P<0.001) with MK-801. In conclusion the findings of present study confirm that in primates, the endogenous excitatory amino acids neurotransmitters may involve in the regulation of basal PRL secretion but PRL secretion in response to insulin-induced are regulated by EAA.