The experiments reported herein prove that wound-associated hyperplasia of frog lenses is inhibited after hypophysectomy. Proliferation can be restored by replacement therapy with either frog pituitary powder or bovine somatotropin. When this is done, division figures are observed after 6 days in the environs of the wound focus and 2 days later in the germinative zone. In the absence of an injury, heightened mitotic activity typically occurs in the germinative zone and subsequently in the polar region. Wound cells in both intact and hypophysectomized frogs bind more tritiated actinomycin D than do cells in the lenses from uninjured frogs. In the latter, the amount of 3H-actinomycin bound does not seem to be affected by hypophysectomy. Wound closure occurs in experimental as well as control animals but the patterns of closure are different. We suggest that cells near the injury in the lenses of hypophysectomized animals may move from G₀ to G1 but are stalled in the latter stage of the cycle.

Keywords:
Frog, Hypophysectomy, Lens injury, Mitotic activity, Somatotropin, Actinomycin, Thyroid, Autoradiography
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© 1976 S. Karger AG, Basel
1976
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