Circadian Periodicity in the Concentration of Prolactin in the Rat Hypophysis

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Science  24 Jan 1964:
Vol. 143, Issue 3604, pp. 375-376
DOI: 10.1126/science.143.3604.375


Prolactin activity in the hypophyses of rats maintained under standardized conditions was assayed in pigeons. The concentration of prolactin in the gland exhibited a circadian rhythm.