206
WILLIAM C. YOUNG
In lower vertebrates much of reproductive behavior, including aggressive and submissive behavior, territorial defense, and locomotor
behavior associated with reproduction, is dependent on gonadal hormones. These hormones are of less importance or have no direct action
in conditioned responses and learning (2), but see Douglas et al. (18).
The latter reported that injections of estradiol benzoate into rats were
followed by an increase in time taken to run a goal-gradient alley. The
weakening of the response was regarded possibly as an alteration in the
functional equilibration of the central nervous system shown by changes
in water balance and by changes in the threshold to some environmental
patterns of stimulation. Throughout the vertebrate phyla hormones of
the embryonic and fetal gonads are important for the patterning of the
behavior displayed after the attainment of adulthood in fishes (19-24),
amphibians (25^30), domestic fowl (31), the guinea pig (32, 33), and
probably the rhesus monkey (33a). In the rat which has a short gestation,
the testes have this role for approximately the first 5 to 10 days postnatally (33a). The role of gonadal hormones in man is controversial (6,
8, 34-36), but not excluded, in the opinion of this reviewer, is the possibility that the vigor of sexual behavior is influenced by these substances.
In subhuman vertebrates and in man the hormones secreted by the
adrenal cortex, thyroid, parathyroid, and islands of Langerhans are
regulatory (37-41) or supportive in the sense that they help to maintain the metabolic balance without which a normal functioning of the
tissues mediating behavior is impossible. (42). No direct action similar
to that of the gonadal hormones has been demonstrated.
The hypophysis may perhaps occupy an intermediate position. Its
secretions are directly or indirectly supportive, but one substance, prolactin, has been closely associated with the migration of certain salamanders from land to water (43-46) and with parental behavior in birds
and the laboratory rat (47-50).
Doubt that the latter relationship is
direct was expressed by the discussants of Dr. Riddle's paper in 1937,
and the basis for cautious reservation is contained in the articles by
Leblond (51, 52) and Leblond and Nelson (53, 54) and in the thoughtfully prepared reviews by Eisner (5) and Lehrman (7). The possibility
that oviposition and spawning of the killifish Fundulus are associated
with neurohypophyseal hormones was suggested by the observation that
vibrating flexures of the body identical with those shown by spawning
males and females are exhibited following the injection of natural vasopressin or oxytocin into intact, hypophysectomized or gonadectomized
subjects (55, 56). As the comment by Aronson (57) indicates, the specific relationship of these vibrations to reproductive behavior has yet to
be demonstrated. Hoar (58) makes a strong case for the participation
WILLIAM C. YOUNG
In lower vertebrates much of reproductive behavior, including aggressive and submissive behavior, territorial defense, and locomotor
behavior associated with reproduction, is dependent on gonadal hormones. These hormones are of less importance or have no direct action
in conditioned responses and learning (2), but see Douglas et al. (18).
The latter reported that injections of estradiol benzoate into rats were
followed by an increase in time taken to run a goal-gradient alley. The
weakening of the response was regarded possibly as an alteration in the
functional equilibration of the central nervous system shown by changes
in water balance and by changes in the threshold to some environmental
patterns of stimulation. Throughout the vertebrate phyla hormones of
the embryonic and fetal gonads are important for the patterning of the
behavior displayed after the attainment of adulthood in fishes (19-24),
amphibians (25^30), domestic fowl (31), the guinea pig (32, 33), and
probably the rhesus monkey (33a). In the rat which has a short gestation,
the testes have this role for approximately the first 5 to 10 days postnatally (33a). The role of gonadal hormones in man is controversial (6,
8, 34-36), but not excluded, in the opinion of this reviewer, is the possibility that the vigor of sexual behavior is influenced by these substances.
In subhuman vertebrates and in man the hormones secreted by the
adrenal cortex, thyroid, parathyroid, and islands of Langerhans are
regulatory (37-41) or supportive in the sense that they help to maintain the metabolic balance without which a normal functioning of the
tissues mediating behavior is impossible. (42). No direct action similar
to that of the gonadal hormones has been demonstrated.
The hypophysis may perhaps occupy an intermediate position. Its
secretions are directly or indirectly supportive, but one substance, prolactin, has been closely associated with the migration of certain salamanders from land to water (43-46) and with parental behavior in birds
and the laboratory rat (47-50).
Doubt that the latter relationship is
direct was expressed by the discussants of Dr. Riddle's paper in 1937,
and the basis for cautious reservation is contained in the articles by
Leblond (51, 52) and Leblond and Nelson (53, 54) and in the thoughtfully prepared reviews by Eisner (5) and Lehrman (7). The possibility
that oviposition and spawning of the killifish Fundulus are associated
with neurohypophyseal hormones was suggested by the observation that
vibrating flexures of the body identical with those shown by spawning
males and females are exhibited following the injection of natural vasopressin or oxytocin into intact, hypophysectomized or gonadectomized
subjects (55, 56). As the comment by Aronson (57) indicates, the specific relationship of these vibrations to reproductive behavior has yet to
be demonstrated. Hoar (58) makes a strong case for the participation