Transgenic female mice with high human growth hormone levels are fertile and capable of normal lactation without having been pregnant.
Transgenic mice carrying the phosphoenolpyruvate carboxykinase promoter region-human growth hormone (PEPCK-hGH) fusion gene are characterized by accelerated growth and plasma hGH levels ranging from 100 to 700 ng/ml. Both sexes are fertile, in contrast to previous findings in metallothionein-I/hGH transgenic mice in which females are sterile, apparently due to luteal failure. Virgin transgenic PEPCK/hGH females from this line produce milk and can successfully raise foster litters to weaning. We conclude that the life-long presence of very large amounts of hGH in the circulation is compatible with ovulation, can override the effects of hGH-induced suppression of endogenous PRL release, and can support full lactation in animals that have not been primed by hormonal changes associated with pregnancy.
Milton
S
S
Department of Physiology, Southern Illinois University, School of Medicine, Carbondale 62901.
Cecim
M
M
Li
Y S
YS
Yun
J S
JS
Wagner
T E
TE
Bartke
A
A
D000818:Animals; D005260:Female; D005298:Fertility / Q000502:physiology*; D013006:Growth Hormone / Q000097:blood / Q000235:genetics / Q000502:physiology*; D007774:Lactation / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012098:Reproduction
D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D013006:Growth Hormone; D010729:Phosphoenolpyruvate Carboxykinase (GTP)