Initiation and Maintenance of Spermatogonial Mitotic        Divisions
{'Code': '08090300', 'Directorate': {'Abbreviation': 'BIO', 'LongName': 'Direct For Biological Sciences'}, 'Division': {'Abbreviation': 'IOS', 'LongName': 'Division Of Integrative Organismal Systems'}}
{'SignBlockName': 'Vincent P. Gutschick', 'PO_EMAI': None, 'PO_PHON': None}
Spermatogenesis is a reproductive process that yields sperm,                    which are unique cells capable of fertilizing eggs and thus                     beginning the life of a new individual.  In animals,                            spermatogenesis occurs via a number of progressive changes in the               shape and behavior of male sex cells.  Among these changes are                  two kinds of cell division.  The first is a simple process                      producing large numbers of stem cells called spermatogonia.  The                second is a unique division, called meiosis, which occurs in two                stages and which results in 4 sperm, each with a reduced number                 of chromosomes.  The objective of the current project is to                     discover the chemical messenger (1) that tells spermatogonia to                 change their behavior and to begin cell division and also the one               (2) that indicates the amount of time such cell division should                 continue.  Therefore, these chemicals are important (1) in                      causing sperm to be produced and (2) in determining how many                    sperm  are produced.  The beginning and maintenance of cell                     division in  spermatogonia are poorly understood processes in all               animal  systems, including mammals.  Walker plans to use the                    Common North Atlantic sea star or starfish in studies of the                    basic  biological process of spermatogenesis because each animal                can produce trillions of sperm in a 5 month period and because                  the spermatogenic process can be studied simultaneously using                   entire, living sea stars or using cells in culture which are                    derived from the tests of these animals.  No other animal                       spermatogenic system permits such close observation of                          spermatogenesis during the important period when spermatogonia                  are beginning cell division.  The importance of this work is that               it should identify chemical messengers that begin and maintain                  sperm production in an animal.  No such messengers have as yet                  been identified for any animal. Estrogens, not androgens (like                  testosterone) provide the initial signal that causes                            spermatogonia to begin to divide and that polyamines, which are                 chemicals produced by spermatogonia or associated cells, then                   cause spermatogonia to continue to divide.  Two chemical                        messengers (and perhaps others) are involved in the process of                  sperm production.  The PI may ultimately be in a position to                    suggest means for external control of sperm production in more                  sophisticated animals like mammals.
{'FirstName': 'Charles', 'LastName': 'Walker', 'PI_MID_INIT': 'W', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Charles W Walker', 'EmailAddress': 'cwwalker@cisunix.unh.edu', 'NSF_ID': '000277247', 'StartDate': '12/01/1987', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of New Hampshire', 'CityName': 'DURHAM', 'ZipCode': '038242620', 'PhoneNumber': '6038622172', 'StreetAddress': '51 COLLEGE RD', 'StreetAddress2': 'BLDG 107', 'CountryName': 'United States', 'StateName': 'New Hampshire', 'StateCode': 'NH', 'CONGRESSDISTRICT': '01', 'CONGRESS_DISTRICT_ORG': 'NH01', 'ORG_UEI_NUM': 'GBNGC495XA67', 'ORG_LGL_BUS_NAME': 'UNIVERSITY SYSTEM OF NEW HAMPSHIRE', 'ORG_PRNT_UEI_NUM': None}
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{'Code': '1141', 'Text': 'PHYSIOLOG & STRUCTURAL SYS'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1987&All=true', 'xml': '8711425.xml'}