352
CHESTER JONES, CHAN, HENDERSON, AND BALL
V. EXTRA-ADRENOCORTICAL ACTIVITY OF ACTH
ACTH has a number of actions which are not mediated directly by
adrenal steroids. Some of these actions are well substantiated while others
require further investigation ( Engel and Lebovitz, 1W6). In mammals,
the extra-adrenal actions include effects upon lipolysis, ketosis, oxygen
consumption, and stimulation of adenylcyclase and phosphorylase activities. Other endocrine glands may also be influenced by ACTH, among
them the thyroid, the ovary, and the juxtaglomerular cells (Engel and
Lebovitz, 1966).
In fishes there are a limited number of observations suggesting extraadrenal actions, Kosto et al. (1959) observed a stimulation of DOPA
tyrosinase and oxygen consumption in isolated fin tissue of Fundulus
heteroclitus chronically treated with ACTH. A stimulation of melanocyte
formation (Kosto et al., 1959; Pickford and Kosto, 1957) and increased
melanogenesis (Chavin, 1959; Hu and Chavin, 1960) also occurred after
ACTH treatment in Fundulus and xanthic goldfish.
A. ACTH and Osmoregulation
Hypophysectomy of freshwater teleosts results in a declination in some
plasma electrolyte concentrations. Species in which this has been demonstrated include Anguilla anguilla (Chester Jones et al., 1965b), Fundulw
heteroclitus (Burden, 1956; Pickford and Atz, 1957; Pickford and Phillips,
1959; Potts and Evans, 1966; Maetz et al., 1967a), Fundulus kunsae (Stanley and Fleming, 1967; Fleming 1967), Xiphophorus sp. (Schreibman
and Kallman, 1966), Poecilia latipinna (Ball and Ensor, 1967), Gambusia
sp. (Chambolle, 1966), and Tilapiu mossambica (Handin et al., 1964).
Apart from the eel, all species mentioned failed to survive in freshwater
following hypophysectomy. Injection of ACTH did not promote survival
of these fishes in freshwater, except in the case of Gambusia, where
ACTH enabled survival and maintained electrolyte balance ( Chambolle,
1967). On the other hand, prolactin treatment of hypophysectomized fish
held in freshwater promoted their survival, and except for the eel
( Olivereau and Chartier-Baraduc, 1966) and Tilapia (Dharmamba et al.,
1967) maintained normal electrolyte values. It was subsequently demonstrated that prolactin decreased the passive movement of sodium across
body surfaces (Potts and Evans, 1966; Maetz et al., 1967a,b), while
ACTH increased active sodium uptake, which was probably mediated
through an increased production of cortisol (Maetz et al., 1967~). Thus,
hypophysectomy of the freshwater teleost caused an increase in sodium
efflux (passive) and a decrease in sodium influx (active), and the species
CHESTER JONES, CHAN, HENDERSON, AND BALL
V. EXTRA-ADRENOCORTICAL ACTIVITY OF ACTH
ACTH has a number of actions which are not mediated directly by
adrenal steroids. Some of these actions are well substantiated while others
require further investigation ( Engel and Lebovitz, 1W6). In mammals,
the extra-adrenal actions include effects upon lipolysis, ketosis, oxygen
consumption, and stimulation of adenylcyclase and phosphorylase activities. Other endocrine glands may also be influenced by ACTH, among
them the thyroid, the ovary, and the juxtaglomerular cells (Engel and
Lebovitz, 1966).
In fishes there are a limited number of observations suggesting extraadrenal actions, Kosto et al. (1959) observed a stimulation of DOPA
tyrosinase and oxygen consumption in isolated fin tissue of Fundulus
heteroclitus chronically treated with ACTH. A stimulation of melanocyte
formation (Kosto et al., 1959; Pickford and Kosto, 1957) and increased
melanogenesis (Chavin, 1959; Hu and Chavin, 1960) also occurred after
ACTH treatment in Fundulus and xanthic goldfish.
A. ACTH and Osmoregulation
Hypophysectomy of freshwater teleosts results in a declination in some
plasma electrolyte concentrations. Species in which this has been demonstrated include Anguilla anguilla (Chester Jones et al., 1965b), Fundulw
heteroclitus (Burden, 1956; Pickford and Atz, 1957; Pickford and Phillips,
1959; Potts and Evans, 1966; Maetz et al., 1967a), Fundulus kunsae (Stanley and Fleming, 1967; Fleming 1967), Xiphophorus sp. (Schreibman
and Kallman, 1966), Poecilia latipinna (Ball and Ensor, 1967), Gambusia
sp. (Chambolle, 1966), and Tilapiu mossambica (Handin et al., 1964).
Apart from the eel, all species mentioned failed to survive in freshwater
following hypophysectomy. Injection of ACTH did not promote survival
of these fishes in freshwater, except in the case of Gambusia, where
ACTH enabled survival and maintained electrolyte balance ( Chambolle,
1967). On the other hand, prolactin treatment of hypophysectomized fish
held in freshwater promoted their survival, and except for the eel
( Olivereau and Chartier-Baraduc, 1966) and Tilapia (Dharmamba et al.,
1967) maintained normal electrolyte values. It was subsequently demonstrated that prolactin decreased the passive movement of sodium across
body surfaces (Potts and Evans, 1966; Maetz et al., 1967a,b), while
ACTH increased active sodium uptake, which was probably mediated
through an increased production of cortisol (Maetz et al., 1967~). Thus,
hypophysectomy of the freshwater teleost caused an increase in sodium
efflux (passive) and a decrease in sodium influx (active), and the species