Comparison of the capacity of anterior‐hypophyseal tissue of mature and immature female rabbits to induce ovulation

Abstract

It has been shown by Smith and Engle ('27) and Zondeli and Aschheim ( '27) that implantation of anterior-lobe tissue into immature female rats or mice stimulated the ovaries of these small animals to activity and a precocious sexual maturity resulted. Furthermore, Smith and Engle demonstrated that the anterior-lobe tissue of immature rats contains amounts of the ovarian-stimulating hormones equal to those found in mature rats. The experiments of Smith and Engle demonstrate that the ovarian-stimulating hormones are present in the anterior pituitaries of immature rats, but, for reasons as yet unknown, these factors either are not released into the blood stream or do not become functionally active in the intact animal until the time of puberty.We have carried out a comparative study in which we have tested the capacity of anterior-hypophyseal tissue, taken from mature and immature female rabbits, to induce ovulation in sexually mature rabbits. The technical procedures were as follows. The donor animal was anaesthetized with ether and then bled to death. The anterior lobe of tho hypophysis was removed and weighed. It was then ground with a small amount of sand in sterile saline; the resulting mixture was centrifuged for twenty minutes and the super-

Experiments on the Gonadotropic Complex of the Anterior Lobe of the Hypophysis

“…Similar results will be obtained with the prehypophysis of rabbits in the adult female rabbit [Wolfe, 1932;Wolfe and Cleveland, 1931]; the quantity which produces luteinization in the rabbit wNill fail to produce it in the infantile female rat or in the mouse [Philipp, 1931].…”

The hormonal control of ovulation in the immature lamb

“…Assay of immature pituitaries revealed the presence of gonadotrophins, but whenever a more specific test for L.H. was applied a deficiency in content was recorded (Wolfe & Cleveland, 1931;Paesi, de Jongh & Hoogstra, 1956). Hollandbeck et al (1956) attributed the onset of puberty to 'the decrease of F.S.H.…”

Maintenance of ovarian and luteal function in the hypophysectomized rabbit by gonadotropic hormones

“…1 The gonadotropic hormone content of the rabbit pituitary per unit of weight is the same in the immature (3-4 months) as in the mature animal [Wolfe & Cleveland, 1931;H ill, 1934a].…”