Relation between plasma prolactin and plasma homovanillic acid in normal subjects

The relation between fasting, a.m. plasma prolactin and plasma/homovanillic acid (HVA) was studied in 9 healthy males on one occasion and in 9 healthy females on two occasions (in the follicular and luteal phase of the menstrual cycle). There was a significant inverse correlation between plasma HVA and plasma prolactin in females in the follicular phase only. The correlation between these two measures, although also in the same direction, was not significant in females in the luteal phase or in males. The theoretical implications of these findings are discussed.