Pulsatile Release of Growth Hormone and Prolactin from the Primate Pituitaryin Vitro*

Abstract
Perifused anterior hemipituitaries from 1 male and 4 female monkeys [Macaca nemestrina] released GH [growth hormone] and PRL [prolactin] in a pulsatile pattern, with mean .+-. SE interpulse intervals of 8.2 .+-. 0.4 and 8.5 .+-. 0.3 min, as determined by a cycle detection computer algorithm. Mean hormone concentrations in the perifusate fractions collected at 2-min intervals were 435 .+-. 89 (GH) and 515 .+-. 262 (PRL) ng/ml. Pulse amplitudes averaged 74 .+-. 16 ng/ml for GH and 189 .+-. 89 ng/ml for PRL. The presence of a high frequency pulsatile secretory mechanism within the primate pituitary is suggested.