News Release

Dairy scientist advances field of transgenics and knowledge of growth hormones

Grant and Award Announcement

Virginia Tech

Blacksburg, Va., Aug. 9, 2000 -- One would expect a dairy science faculty member at a major research university to advance the understanding of milk synthesis and lactation physiology and increase productivity in the dairy industry. In less than 20 years, Virginia Tech dairy scientist R. Michael Akers has also greatly advanced the understanding of mammary gland development, discovered new information about growth factors, and contributed to transgenic technology worldwide.

For his long-term excellence in mammary gland research in dairy cattle and humans, Akers, has earned Virginia Tech's Alumni Award for Research Excellence. The award will be presented Sept. 20 during the university's Fall Awards Convocation. Akers also recently received the Pharmacia and Upjohn Physiology Award, presented at the American Dairy Science Association annual meeting. "It's been quite a year," he says.

One of Akers main areas of research is the hormonal regulation of mammary development in young animals in relation to stage of development, nutrition, and hormonal manipulations. His studies yielded important new knowledge concerning the role of the ovary and ovarian hormones in regulation of mammary development.

He was the first to note the absence of growth hormone-receptors in mammary tissue and was among the first to characterize the hormones associated with mammary cell growth and with differentiation of the secretory epithelial cells that make up the lining of the mammary gland.

Akers discovered that insulin-like growth factor (IGF) is produced not only in the liver and circulated in the blood stream, but is also produced locally in the mammary gland and in the connective tissue surrounding the epithelial tissue. "It is the local production of IGF-1 that regulates mammary development," he says.

He explains, "For a number of years, the focus of the lactation research program has been to elucidate mechanisms of how hormones and growth factors influence the development and function of the mammary gland. We focused on development of techniques suitable for study of mammary cell proliferation, study of overexpression of IGF-1, and comparative study of formation and differentiation of mammary tissue."

His techniques included the creation of transgenic bovine mammary epithelial cells that secrete recombinant ovine IGF-1. He and his students studied developmental patterns for the cells and effects of inserting foreign gene sequences into the cell DNA on secretion of IGF-1. Such studies may also have application for understanding the role of growth factors in development of breast cancer since IGF-1 is involved in some cancers.

He subsequently produced transgenic mice that synthesize and secrete rIGF-I in their mammary tissue, confirming that local IGF influences mammary development.

Because Akers also observed that mammary tissue in rodents is distinctly different from that of ruminants, he does research with cows and sheep, in addition to using the rodent model, to study the effects of ovarian hormones and nutrition on local mammary tissues synthesis and secretion of IGF-1 and related binding proteins. As a result, he also discovered that the involvement of the ovary in regulation of peripubertal mammary development is different in cattle than in sheep. And while both are different than human, they are more similar in structure to humans than rodents are to humans, he notes.

William Drohan, senior director of plasma development at the American Red Cross, reports that Akers' research techniques "provided some of the earliest groundbreaking and most difficult work in the scientific development of transgenic animals. As a result of this pioneering work, transgenic animal technology holds tremendous promise for the large-scale production of life-saving human therapeutic drugs in quantities far greater than could ever be produced through fractionation of human blood.

Akers' creative thought led to the early recognition of the tremendous potential of the mammary gland as a bioreactor for the production of pharmaceutical proteins, Drohan says. "Dr. Akers has been an extremely important contributor to the American Red Cross transgenic animal research program. He assisted in the development of DNA constructs, which were put into animals to optimize the expression of proteins in their mammary glands. This led to the successful production of the first transgenic pig in the United States."

Aker's research contributions to the Red Cross program, which began in the late 1980s, continues to influence the current program of isolating additional proteins, establishing herds of transgenic animals, and the commercial production of products," Drohan says. "His contributions and insights into the basic science of transgenic technology and mammary gland development have contributed ... to transgenic research worldwide."

Kris Sejrsen, senior scientist and group leader at the Danish Institute of Agricultural Sciences, reports that Aker's studies with transgenic mice have yielded significant new insight into the involvement of IGF-I and IGF binding proteins in regulation of mammary gland development and function. The results are important not only in the context of dairy science but also in relation to breast cancer."

Akers studies of mammary development and differentiation in the dry period and during lactation have also resulted in interesting new findings concerning the balance between cell proliferation and milk synthesis, Sejrsen says. He reports that Akers was the first to prove that prolactin is essential for normal onset of lactation in ruminants.

"A significant factor in (Akers) success as a scientist is his excellent skills and ingenuity in applying and developing techniques… He was the fist to show that iodinated human GH could be used to measure prolactin receptors in cattle. His expertise in applying cell culture techniques is unsurpassed, Sejrsen says, adding that Akers has "the best skills and most experience in applying histological techniques to studies on ruminant mammary glands."

Sejrsen also praises Akers' "remarkable ability to collaborate with other scientists," noting that his more than 120 publications have co-authors from different disciplines, universities, countries, and continents. "This is a quality that cannot be underestimated, since the rapid advancements of new techniques makes collaboration a must for a successful scientist."

"Any success that I have had has depended on the excellent students and collaborators that I have had over the years," Akers says. "I have also been very lucky to have had an excellent technican in my lab, Ms. Patricia Boyle, for many years."

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Akers' research has been supported by PPL Therapeutics, Inc. and Hatch since 1997. He has received two USDA National Research Initiative Competitive Grants totaling almost $250,000 since 1993. And he and Kim Forsten in chemical engineering received $164,000 from the Whitaker Foundation for quantitative engineering analysis of growth factor stimulation and regulation in a breast cancer model cell system.

His excellence has been recognized throughout his career. He received the 1986 Young Scientist Award and the 1993 Borden Award from the American Dairy Science Association, was named the Horace E. and Elizabeth F. Alphin Professor in 1996, received the Gamma Sigma Delta Honor Society Research Award of Merit in 1996, and was named the AgResearch Senior Research Fellow at the Ruakura Agricultural Research Centre in New Zealand.

Akers is senior editor of the Journal of Dairy Science, on the editorial boards of three other journals, and was a panel member of the Breast Cancer Research Program of the Department of Defense for three years.

Akers received an associate degree from Wytheville Community College in 1972, his undergraduate and master's degree at Virginia Tech, and his Ph.D. from Michigan State University in 1980. He joined Virginia Tech's faculty in 1981. He teaches Anatomy and Physiology of Domestic Animals, a required course of animal science, dairy science and poultry science students, and the graduate Lactation Physiology course for agriculture, biochemistry, and biology majors.

PR CONTACT: Susan Trulove
540-231-5646 STrulove@vt.edu



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