Until recently, it has been generally accepted that growth hormone (GH) and prolactin are invariably secreted by separate and distinct cell types within the pituitary gland. However, experiments conducted over the past two years in my laboratory have necessitated a reevaluation of this view. Utilizing reverse hemolytic plaque assays, that enable the detection of hormone release at the single cell level, we have identified individual pituitary cells that simultaneously release both GH and prolactin. These dual cells, designated mammosomatotropes, account for approximately one-third of all GH and/or prolactin secretors in pituitary cultures derived from mature and neonatal rats of both sexes. The long-term objective of the proposed study is to delineate the secretory characteristics of mammosomatotropes and then to clarify the functional relationship between these dual hormone secretors and those cells that release only one hormone or the other. In pursuit of this objective, we plan to address two specific questions: 1) Does the control of hormone release from mammosomatotropes differ from that of classical mammotropes and somatotropes? and 2) Are GH and prolactin cells functionally interconvertible? This will be accomplished, in large part, by first exposing cultures of pituitary cells to various experimental treatments and then by using plaque assays to monitor the effects on hormone release by cells that secrete GH, prolactin, or both hormones. It is anticipated that the proposed studies will provide valuable information toward our basic understanding of GH and prolactin regulatory processes. Such knowledge is essential for identifying the causes of, and developing treatments for, GH and/or prolactin secreting adenomas of the pituitary.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK038215-03
Application #
3237496
Study Section
Endocrinology Study Section (END)
Project Start
1986-04-01
Project End
1989-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
3
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Medical University of South Carolina
Department
Type
School of Medicine & Dentistry
DUNS #
183710748
City
Charleston
State
SC
Country
United States
Zip Code
29425
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Morrison, Elizabeth D; Brandhagen, David J; Phatak, Pradyumna D et al. (2003) Serum ferritin level predicts advanced hepatic fibrosis among U.S. patients with phenotypic hemochromatosis. Ann Intern Med 138:627-33

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