Effects of growth hormone and estrogen on T lymphocytes in older women.
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.
Bonello
R S
RS
Department of Internal Medicine, Stanford University School of Medicine, California 94304-5111, USA.
Marcus
R
R
Bloch
D
D
Strober
S
S
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*
D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D017493:Leukocyte Common Antigens