Science: Prolactin

In 1929 Scientist Karl Ehrhardt of Germany published photographs of a female monkey holding a young guinea pig in a maternal manner. This foster mother had been injected with a crude extract from pituitary glands. In 1932 Dr. Oscar Riddle and his associates at the Carnegie Institution's station for experimental evolution on Long Island obtained in almost pure form the same pituitary substance which had made Ehrhardt's monkey act like a mother. Because it was a stimulant of milk secretion this substance was called prolactin.

Prolactin was found to induce mammary activity in virgin...

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