Father of the Oral Contraceptive Pill" Gregory Pincus' Further Studies on the Parthenogenetic Activation of Rabbit Eggs, 1940

Pincus, G., & Shapiro, H., Further Studies on the Parthenogenetic Activation of Rabbit Eggs. Reprinted from the Proceedings of the National Academy of Sciences, Vol. 26, No. 3, pp. 163-165, March, 1940. Stamped en recto: "Presented by Dr. E.N. Harvey to the Zoology Department Library, University of North Carolina." Brown stapled covers, measures 7" x 10", 3 pages.

Pincus was a leading researcher at Harvard University, conducting experiments on mammalian biology, when he made one of the major breakthroughs in his career: successful in vitro fertilization of a rabbit in 1934. While the importance of this research was acknowledged by all, (truncated) the controversy surrounding it was overwhelming, and it cost Pincus his faculty position at Harvard University. In 1938, he joined the faculty at Clark University in Worcester, MA and in 1944, he co-founded the important research center Worcester Foundation for Experimental Biology. At these institutions, Pincus continued his work in mammalian reproduction and steroid hormone use. His outstanding work in this field brought him to the attention of Margaret Sanger, who met with him in 1951 and supported his work towards developing the oral contraceptive pill. This article was published in the midst of his in vitro experimentation on test rabbits. Some take away points of this study is as follows:

"1. The eggs of many mammalian species show signs of early parthenogenetic development as they age after ovulation and oocytes may form transplantable terato-carcinomas. These cases of apparently spontaneous parthenogenetic development suggest that the cells of the female germ line have an inherent tendency to divide and differentiate.

2. The ovulated eggs of virgin female mammals may be stimulated to start parthenogenetic development by a wide variety of treatments. Most of these damage the egg so that it does not develop beyond the 4 cell stage. However if the eggs are exposed to electrical activation, hyaluronidase treatment, or temperature shock then in many cases they will develop into blastocysts.

3. These blastocysts may be either haploid or diploid. Haploid blastocysts may be formed either by the egg extruding the nucleus of the second polar body or by the egg dividing in half, so that the female pronucleus is in one cell and the nucleus of the second polar body is in another cell. Diploid blastocysts are formed by the retention of the nucleus of the second polar body within the egg. The way in which the egg develops may be controlled by altering the osmolarity of the culture medium, the age of the egg at the time of activation, or the strain of animal used.

4. The action of the sperm on the egg can be defined by comparing the events of normal fertilization and parthenogenetic activation. Both these stimuli cause the egg to expose binding sites for Concanavalin A to synthesize DNA and to divide. However, the release of cortical granules, which occurs after fertilization, does not appear to be induced by parthenogenetic activation, and it is significant that parthenogenones lack the sperm nucleus and mitochondria.

5. The majority of parthenogenones die soon after implantation. Death at this time occurs with parthenogenones obtained from the activated eggs of both inbred and outbred stocks. Death might be caused by recessive lethal mutations or by extra-genetic effects of the maternal chromosomes.

6. Parthenogenones contain endogenous A-type particles which shows that these bodies are inherited through the female germ line.

7. Parthenogenones may in the future provide both a method for chromosome mapping and a source of haploid cells." C.F. Graham (1974)

At this stage of experimentation, it was concluded that one egg in over 200 developed into a living rabbit, a lower percentage than natural development. Covers clean and binding tight, a minor water stain to the right edge of interior pages, does not affect text. Overall very good condition. The impact of his work was tremendous--by 1965, one out of every four married women in America under 45 had used the pill, and by the time Pinkus passed away in 1967, nearly 13 million women worldwide were using it. (Inventory #: 21220)