Intraventricular administration of histidyl-proline-diketopiperazine [Cyclo(His-Pro)] suppresses prolactin secretion and synthesis: a possible role of Cyclo(His-Pro) as dopamine uptake blocker in rat hypothalamus.
Jikihara H, Ikegami H, Koike K, Wada K, Morishige K, Kurachi H, Hirota K, Miyake A, Tanizawa O. Intraventricular administration of histidyl-proline-diketopiperazine [Cyclo(His-Pro)] suppresses prolactin secretion and synthesis: a possible role of Cyclo(His-Pro) as dopamine uptake blocker in rat hypothalamus. Endocrinology. 1993 Mar; 132(3):953-8.