Abstract
Summary
S. mansonoides spargana produce a potent “worm factor” that causes both the generation of somatomedin and linear growth in hypophysectomized rats without detectable immunoassayable rat growth hormone (RGH). Implantation of these spargana has no significant effect on the growth of normal rats but did cause a 34% decrease in pituitary weight (p < .001) and a 68% decrease (p < .001) in pituitary RGH content. Hemipituitaries removed from these rats released a normal proportion of their RGH during a control incubation and responded with an appropriate increase during stimulation by high potassium. Either the “worm factor” has growth hormone-like action on the hypothalamus or pituitary, or somatomedin itself plays an important role in the feedback regulation of pituitary growth hormone.
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