Clyde Biddulph

Gonadotrophic hormone secretion in immature hypophysectomized parabiotic rats.

Summary Using immature hypophysectomized-gonadectomized parabiotic rats it has been demonstrated that following gonad removal in both sexes follicular stimulation only is obtained in the ovaries of the hypophysectomized parabiont for as long as 53 days following the operation. If the hypophysectomized partner is a male, the testes are maintained in the scrotum and their average weight is somewhat less than that of normals, whereas the weight of the accessory glands is approximately the same as that of normal animals. Approximately 17% of the pairs failed to show any gonadal stimulation following the hypophysectomy-gonadectomy procedure. This percentage failure is slightly greater than that occurring in nonhypophysectomized pairs.

Adenosine triphosphatase activity and weight of corpora lutea during reproductive cycle of the rat.

Summary The ATP-ase activity and weight of lutein and ovarian tissue were determined during estrus, diestrus, pseudopregnancy, pregnancy and lactation. The results indicate that in general the enzyme activity per unit weight is lower in functional corpora lutea than in apparently non-functional corpora. The weight and enzyme activity per corpus luteum increased and decreased at approximately the same rate during pregnancy and lactation. The enzyme activity of ovarian tissue remaining after the removal of the corpora lutea was greatest on the 4th day of pseudopregnancy, 7th day of pregnancy and 11th day of lactation.

Luteinization of the Ovaries of Immature Hypophysectomized Parabiotic Rats with Gonadotrophic Hormone Preparations.

Summary The injection of LH, gonadotrophin prepared from the urine of pregnant women, and unfractionated sheep pituitary extracts into the nonhypophysectomized partner produced luteinization in the ovaries of the hypophysectomized partner of either hypophysectomized-gonadectomized or hypophysectomized-normal parabiotic rats. The results indicate that the failure of the ovaries of the hypophysectomized partner of hypophysectomized-gonadectomized pairs to develop corpora lutea is due to an insufficient secretion of LH following gonadectomy rather than to an unresponsive state of the ovaries of the hypophysectomized animal.