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Effects of prolactin and growth hormone on growth and metamorphosis of tadpoles of the frog, Rana pipiens.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Brown, Patricia Frye, Billy E. |
| Copyright Year | 1969 |
| Abstract | Mammalian prolactin at doses of l-50 pg/day promoted growth (increased wet weight, dry weight and body length) in Rana pipiens tadpoles. Mammalian growth hormone (GH) promoted growth only at the higher doses (50 pg/day and above) and was not so effective as prolactin. Prolactin also inhibited metamorphosis (at doses of 5 pg/day and above). Inhibition of metamorphosis did not appear to be due to reduction in tissue sensitivity to thyroxine since prolactin-treated tadpoles metamorphosed in response to exogenously administered thyroxine (4-100 #g/liter) to the same extent as controls. Prolactin promoted further growth in tadpoles in which the thyroid level had been reduced with thiouracil or by thyroidectomy. This indicates that growth promotion caused by prolactin is not just the result of thyroid inhibition, although it is possible that a portion of the growth stimulation is due to t?i8 sntithvroid action of prolactin. .,. '. ,, < _::. The pituitary gland of amphibians has been thought to be necessary for normal growth in anuran tadpoles since the early work of Allen (1916) and Smith (1916) with hypophysectomized tadpoles. The suggestion that prolactin may be the pituitary hormone necessary for normal growth in amphibians is more recent (Etkin and Lehrer, 1960). Etkin and Lehrer found that R. pipiens tadpoles that had had their pituitary transplanted to the tail grew larger than control tadpoles, and suggested that the transplant might be releasing a growth factor in excess which was inhibited when the pituitary was in its normal location. Since mammalian pituitaries are known to |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0016-6480(69)90229-9 |
| PubMed reference number | 5804506 |
| Journal | Medline |
| Volume Number | 13 |
| Issue Number | 1 |
| Alternate Webpage(s) | https://deepblue.lib.umich.edu/bitstream/handle/2027.42/32919/0000301.pdf?sequence=1 |
| Alternate Webpage(s) | https://doi.org/10.1016/0016-6480%2869%2990229-9 |
| Journal | General and comparative endocrinology |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
