Time Factor Relationship of Follicle Stimulation and Luteinization in the Immature Rat

Abstract

In a previous communication from this laboratory it was shown that both luteinizing and follicle stimulating reactions can be obtained with extracts prepared by the acetone precipitation method 1 from castrate and post-menopause urines. It was also demonstrated that with the same extract either pure follicle stimulation or luteinization or combinations of both effects may be obtained by varying the dosage of the extract injected. 2 In these studies all the animals were sacrificed 96 hours after the first injection.

The present investigation was undertaken to determine the effect upon the ovarian reaction produced by varying the time factor.

The gonadotropic material used was obtained from the 4 following sources: (1) castrate urine prepared by the acetone precipitation method, (2) whole pregnancy urine, (3) anterior hypophysis ‘Maturity’ Factor† (Collip), (4) placenta ‘A.P.L.’† (Collip). Litter mate immature female rats 25-30 days old were used in the majority of the experiments. In a few instances the animals were not litter mates but were of approximately the same age and weight.

In one series of experiments immature rats were injected with the equivalent of 200 cc. of castrate urine (sufficient to produce luteinization at the end of 96 hours), and the animals were sacrificed at intervals of 48-96 hours. The ovaries were then examined in serial sections.

A similar experiment was performed using whole pregnancy urine.

In another series of experiments other animals were injected with ‘Maturity Factor’, ‘A.P.L.’, and castrate urine extracts. Laparotomies were performed at intervals varying from 26 to 72 hours after injections were started and one ovary removed. The animals were then sacrificed at different time intervals varying from 52 to 144 hours after the first injection. The ovaries were serially sectioned.