The effects of salinity, hypophysectomy and hormone administration on gill RNA metabolism of the euryhaline teleost, Fundulus kansae

Abstract

1. 1. The specific activity ( 32P incorporation) of the gill ribosomal RNA and soluble RNA fractions was decreased in both one third and full strength sea-water adapted animals compared to those held in fresh water. 2. 2. Hypophysectomy of sea-water adapted fish increased the specific activity of the soluble tissue nucleotide fraction; hypophysectomy may have altered the ratio of incorporation of 3H-uridine and 14C cytosine into r-RNA. 3. 3. ACTH lowered the specific activity of the soluble tissue nueleotide pool in hypophysectomized, sea-water adapted fish; ACTH altered the U C ratio of the r-RNA. 4. 4. Prolactin injections caused little change in the U C ratio in hypophysectomized, sea-water adapted fish, but probably did cause a decrease in RNA specific activity. 5. 5. It is suggested that the lack of conclusive influences of ACTH and prolactin on gill RNA metabolism indicates that exogenous factors, such as ion balances and ratios, may play a key role in RNA changes associated with osmoregulation.