THE GONADOTROPIC HORMONES (-FACTORS). —I. THE PREPARATION AND PROPERTIES OF EXTRACTS OF ANTERIOR LOBE, PLACENTA, AND PREGNANCY URINE

¹ Macaulay Laboratory, Institute of Animal Genetics, University of Edinburgh

(1) Two methods for the preparation of potent extracts containing the -factors from pregnancy urine have been elaborated, one of which involves the use of phosphotungstic acid as a precipitant, whilst the other is an alcohol precipitation method with various refinements introduced.

(2) Methods are also given for the preparation of active extracts from the anterior lobe of the pituitary and human placenta.

(3) The effect of prolonged injections of small quantities or fewer injections of large quantities of -factors is to inhibit the strous cycle in the mature mouse, whilst small quantities actually induce premature strus in immature mice. A theory is enunciated to account for these phenomena.

(4) The active factors are not precipitated to any appreciable extent by dialysed iron, nor can they be ultrafiltered through an "ultrafein" membrane filter which is just impermeable to Congo red. Other chemical properties are in accord with the observations of previous workers.