title: Effects of growth hormone and estrogen on T lymphocytes in older women.
abstract: OBJECTIVE
  To assess the effect on peripheral blood T lymphocytes of recombinant human growth hormone administered to healthy older women.
  
  
  METHODS
  Prospective, open study.
  
  
  METHODS
  Veterans Administration clinical research unit and community surrounding Palo Alto, California.
  
  
  METHODS
  Thirty-three women were recruited in two age groups: 20 to 40 years (n = 13) and 70 years or older (n = 24). Subjects were healthy, community-dwelling volunteers.
  
  
  METHODS
  Recombinant human growth hormone at a dose of 0.025 mg/kg body weight/day was administered to the older subjects by daily subcutaneous injection over a 6-month study period.
  
  
  METHODS
  Mean percentage and number of peripheral blood CD45RA + ("naive") T cells, mean counts per minute (CPM) of [3H]-thymidine incorporation following stimulation of peripheral blood mononuclear cells with phytohemaglutinin (T cell proliferation).
  
  
  RESULTS
  Before therapy, mean percentage and number of peripheral blood CD45RA + T cells and T cell proliferative responses were significantly reduced in older compared with younger women. The fraction of older women with CD45RA + T cell levels or T cell proliferative responses in the young range was significantly decreased in those who were receiving estrogen (1/10) compared with those who were not (9/14). After treatment with growth hormone, there were no significant changes in the mean CD45RA + T cell levels or proliferative responses of the older women.
  
  
  CONCLUSIONS
  The results suggest that T cell changes associated with the age-related decline in secretion of growth hormone cannot be reversed by growth hormone therapy during the eighth decade.
authors.affiliation: Department of Internal Medicine, Stanford University School of Medicine, California 94304-5111, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Bonello
authors.forename: R
authors.initials: R
authors.lastname: Marcus
authors.forename: D
authors.initials: D
authors.lastname: Bloch
authors.forename: S
authors.initials: S
authors.lastname: Strober
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000187:drug effects* / Q000276:immunology*; D015914:Estrogen Replacement Therapy; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000097:blood; D018655:Lymphocyte Count; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects*
chemical_list: D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D017493:Leukocyte Common Antigens