WATER DRIVE STUDIES ON HYPOPHYSECTOMIZED EFTS OF DIEMYCTYLUS VIRIDESCENS. PART I. THE ROLE OF THE LACTOGENIC HORMONE

¹ Department of Biology, Williams, College, Williamstoun, Massachusetts

1. Other investigators have shown that the land (eft) stage of Diemyctylus viridescens can be induced to enter water and assume adult pigmentation and morphological characteristics following treatment with various pituitary preparations. Hypophysectomized efts were used in the present experiment in order to assure positive identification of the active, water drive principle.

2. Operated animals treated with LH, growth hormone, ACTH, posterior pituitary preparation, TSH, Antuitrin S and melanophore-stimulating hormone gave a negative response. Eight-milligram injections of FSH produced water drive in several animals, but this was most probably due to the contamination of the substance with prolactin.

3. Most hypophysectomized efts, with the exception of those receiving TSH, either failed to molt or underwent an abnormal molt after the animals had been induced to enter water.

4. Operated animals receiving injections of prolactin (240 to 1.05 I.U.) migrated to water from 4 to 10 days following treatment. However, they failed to acquire adult pigmentation and associated characteristics.

5. The lactogenic hormone has been identified as the principle which initiates the migration of efts to water and the water drive test for prolactin is considered to be reliable.

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