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Effects of 17beta-estradiol and p-nonylphenol were examined in the immune and endocrine organs of Japanese quail embryos. The test compounds were injected into the yolk of embryonated eggs. Injection of estrogen resulted in (1) disappearance of lymphoid cells and flattened development of plicae in the bursa of Fabricius, (2) decreased area of thyroid follicles and height of simple cuboidal epithelial cells in the thyroid, (3) increased follicular appearance of the thymus, and (4) development of an ovotestis in male embryos. Injection of nonylphenol did not induce flattened plicae in the bursa of Fabricius or development of an ovotestis in male embryos, but it increased the disappearance of lymphoid cells from the lymphoid follicles in the bursa, decreased the height of simple cuboidal epithelial cells surrounding the thyroid follicle, and increased the follicle-like structure in the thymus in male embryos. These results suggest that nonylphenol has estrogenic effects, but these are low compared to those of estrogen itself.

This study assesses the effects of ambient light conditions, under a thermoneutral environment, on selected immunological parameters of 7 healthy young women (aged 19 to 22 yrs). Subjects entered the bioclimatic chamber at 11: 00 h, controlled at 26 degrees C and 60% relative humidity, a "neutral climate". They lead a well-regulated life in the climatic chamber (pre-condition) while exposed to dim (200 lux) or, on the next day, bright (5000 lux) light between 06 : 00 to 12 : 00 h. Just before the end of each period of light exposure, a blood sample was taken for later immunological assay of white blood cell count (WBC), phagocytosis, interferon-gamma (IFN-gamma), interleukin-4 (IL-4), CD69 T cells (CD69), CD4+CD25+ T cells (CD4+CD25+), and transforming growth factor-beta 1 (TGF-beta1). The results, when compared with the pre-condition, were as follows: 1) CD69 and IFN-gamma increased during normal conditions without thermal stress under dim light; 2) WBC increased and IL-4 decreased under bright light; 3) as shown by the highly significant decrease of TGF-beta1, the immune system was activated under bright light; 4) phagocytosis tended to increase under bright light exposure; 5) CD69 and IFN-gamma were significantly higher, and CD4+CD25+ tended to decrease under bright light; 6) phagocytosis tended to be lower and TGF-beta1 significantly higher under dim light, indicating a decline of immune system function. Taken together, this preliminary single time-point sampling study infers that some parameters are activated (CD69) while others are attenuated (phagocytosis, TGF-beta1) according to the environmental light intensity, dim vs. bright, in women adhering to a standardized routine in the absence of thermal stress. These findings are discussed in terms of inhibition of the sympathetic and excitation of the parasympathetic nervous system under the influence of life-style regularity and daytime bright light exposure.

We investigated the correlation between torpor frequency and capacity for non-shivering thermogenesis (NST) in Siberian hamsters (Phodopus sungorus) during 25 weeks of acclimation to cold and short days. We hypothesized that torpor use is conditioned on the development of brown adipose tissue (BAT) capacity for NST. We found that (1) the degree of noradrenaline (NA)-induced hyperthermia was positively correlated with torpor frequency and its length and depth, and (2) the maximum response to NA occurred at the time of day when hamsters naturally arouse from torpor. The present study quantifies the correlation between torpor frequency and NST capacity and we suggest that a welldeveloped NST capacity is a prerequisite for the occurrence of torpor. r 2004 Elsevier Ltd. All rights reserved.

We investigated the photoperiodic response of serotonin- and galanin (GA)- immunoreactive (ir) cells in the paraventricular organ (PVO) and infundibular nucleus (IF) of the Japanese quail and the interaction of these cells with gonadotropin-releasing hormone (GnRH)-ir neurons in the hypothalamus. Serotonin-ir cells were located in series from the PVO to the IF, and were connected with each other. The number of serotonin-ir cells differed significantly between light and dark phases on the short days (SD), but did not differ between light and dark phases on long days (LD). GA-ir cells were also found in the PVO and IF. The number of GA-ir cells under SD conditions was significantly greater than under LD conditions but did not change diurnally. Both serotonin-ir and GA-ir fibers ran along the GnRH-ir cells in the nucleus commissurae pallii. Serotonin-ir and GA-ir fibers were connected with the GnRH-ir fibers in the external layer of the median eminence (ME). We confirmed that GA-ir fibers were closely associated with serotonin-ir neurons in the PVO and IF. GA-ir neurons have at least 2 routes of regulating GnRH neurons directly, and indirectly via the serotonin-ir cells in the PVO and IF.

The pineal complex, deep brain, and skin have been known to function as extraretinal photoreceptors in non-mammalian vertebrates. To see the diversity of localization of extraretinal photoreceptors in lower vertebrates having different habitats, we analyzed the opsin-like immunoreactivities in anuran amphibians, Xenopus laevis, Rana catesbeiana, Rana nigromaculata, and Bufo japonicus. An antiserum (toad Rh-AS) was raised against rhodopsin purified from the retinas of Japanese toad, B. japonicus. In the retina of all the anurans examined, the outer segments of rods were immunopositive to toad Rh-AS. The outer segments of most pinealocytes were immunopositive in R. catesbeiana, R. nigromaculata, and B. japonicus. The outer segments of photoreceptor-like cells within the frontal organ of R. nigromaculata were immunostained. Interestingly, toad Rh-AS immunostained many secretory cells of mucous glands in the head skin of B. japonicus, implying the presence of a novel photoreceptive molecule. Within the hypothalamus, toad Rh-AS immunostained many cells in the magnocellular preoptic nucleus of R. catesbeiana and B. japonicus. Toad Rh-AS also labeled cerebrospinal fluid (CSF)-contacting cells in the anterior preoptic nucleus of R. nigromaculata and those adjacent to the lateral ventricle within the septum of R. catesbeiana. Thus the distribution patterns of the rhodopsin-like immunoreactivities among the anurans were highly diverged, and there was no relationship between the distribution patterns and their habitats. J. Exp. Zool. 286:136-142, 2000.

Nonmammalian vertebrates have been known to have photoreceptors in their pineal complex and deep brain as well as the retina. The extraretinal photoreceptors are believed to be essential for seasonal reproduction and regulation of circadian physiology. In this review, we discuss the relation between extraretinal photoreceptors and circadian systems in some species of nonmammalian vertebrates in terms of the pineal as the photoreceptor and oscillator for circadian rhythms, the hypothalamus as a photoreceptor and the extraretinal photoreceptors as the multi-oscillator system for circadian behavioral rhythms. Although immunohistochemical results suggest the existence of rod- and cone-type photoreceptors in the pineal, photoreception in the pineal is not always necessary for circadian systems in nonmammalian vertebrates. Circadian systems are involved in avian photoperiodic gonadal responses, and these responses are induced via deep brain photoreceptors. In some animals, deep brain photoreceptors are stained by antisera against photoreceptor proteins (rhodopsin, iodopsin and transducins). The relationship between the oscillators and photoreceptors is different among species. Physiological significance of this diversity is discussed from evolutional and developmental points of view.

In the retina of the medaka four kinds of retinal cone photoreceptor cells are arranged in a simple, repeating organizational pattern known as a square mosaic. We found that the distribution of cones in the retina could be easily detected by autofluorescence-emission from the photoreceptor cells without any staining. In tangential sections of the retina, cones were located at a specific position in a crystalline lattice as follows: Double cone pairs display a zigzagging appearance, oriented roughly 90-120 degrees to one another, and single cones were in the center of the square consisting of four double cone pairs. In order to determine the continuity of this regular arrangement on the spherical surface, the distribution of this cone mosaic pattern was examined in central, dorsal, ventral, nasal and caudal areas of the retina. The regular arrangement of cones was confirmed in the whole retina. Double cones and single cones are in their respective lines and these lines form a lattice-work. As a re...

Relation between retinal melatonin and corneal mitotic rhythms in the Japanese quail was investigated in experiments manipulating the ocular physiology by treatments with formoguanamine hydrochloride (FG) and eye-lid suture. In experiment 1, we investigated the effects of FG, which is known to induce photoreceptor degeneration, on retinal melatonin and corneal mitotic rhythms. FG-treatment completely abolished the retinal melatonin rhythms in both LD 12:12 and constant darkness (DD), but the corneal mitotic rhythm was maintained with high mitotic rate in darkness under a LD cycle and subjective night under DD. The result suggests that 1) the photoreceptor cells in the retina are the site for melatonin production and/or for the oscillator which drives the circadian rhythm in retinal melatonin, and 2) melatonin is not involved in generation of the corneal mitotic rhythm. In experiment 2, we investigated the effects of eye-lid suture, which is known to induce eye enlargement and bulgy cornea, on the retinal melatonin and corneal mitotic rhythms. Eye-lid suture abolished the corneal mitotic rhythm in both LD and DD, with a high mitotic rate being maintained throughout 24 hr. But retinal melatonin maintained its rhythm with high levels in darkness under a LD cycle and in subjective night under DD. The result suggests that 1) bulgy cornea in the sutured eye was induced by the increase in mitotic rate in the light period, and 2) disappearance of the corneal mitotic rhythm does not have a relation to retinal melatonin. These results suggest that retinal melatonin is not involved in generation of the corneal mitotic rhythm and that there are two circadian clock systems in the eye.

The aim of this study has been to examine whether iodopsin immunoreaction exists in the photoreceptor cells of the retina of the river lamprey, Lampetra japonica, and whether this immunoreaction also appears in the photoreceptors of the pineal complex. The lamprey retina possesses long and short photoreceptor cells that display iodopsin immunoreactivity and rod-opsin immunoreactivity, respectively. In the pineal organ, iodopsin immunoreaction has been observed in the peripheral region and the dorsal wall of the end-vesicle. Immunoreactivity is also found in the atrium and the pineal stalk. The iodopsin-immunoreactive outer segments are smaller than those displaying rod-opsin immunoreactivity. In the parapineal organ, iodopsin immunoreactivity is distributed in both dorsal and ventral portions. Double immunostaining has been employed to investigate whether iodopsin and serotonin immunoreactivities are colocalized in one and the same cell. This approach has revealed that the iodopsin-immunoreactive outer segments belong to serotonin-immunopositive and to serotonin-immunonegative photoreceptor cells. These results demonstrate that rod-type or cone-type visual pigments are contained in both typical and modified pineal photoreceptors.

We investigated localization of visual pigments in the pineal complex of Japanese quail, Japanese grass lizards and bullfrogs immunocytochemically by use of the antiserum against bovine rhodopsin (Rh-As) and monoclonal antibodies against chicken iodopsin (Io-mAb). We also analyzed retinoids, chromophores of visual pigments, by a high performance liquid chromatography (HPLC). The outer segments and cell membranes of some photoreceptor cells in the pineal organ of the Japanese quail exhibited immunoreactivity to Rh-As, but there are also many immunonegative cells. The number of immunoreactive cells among individuals varied. Immunoreactivity to Io-mAb was weak or did not exist. The HPLC analysis revealed peaks of 11-cis and all-trans isomers of retinal in the oxime extracts of the pineal organ of Japanese quail and chickens. In the pineal of Japanese grass lizards, the outer segments of some cells were immunopositive to Io-mAb, but there were no cells immunoreactive to Rh-As. The parietal eye exhibited a well-developed lens and photoreceptor cells, but the outer segments of photoreceptor cells were immunonegative to both Rh-As and Io-mAb. In bullfrogs, three types of cells were identified in both the pineal and frontal organ; (1) immunopositive to Rh-As, (2) immunopositive to Io-mAb and (3) immunonegative to either of the antibodies. In the pineal organ of bullfrogs, 11-cis and all-trans retinal and 11-cis 3-dehydroretinal were detected, and 11-cis and all-trans retinal were also detected in the frontal organ. We detected 11-cis and all-trans retinal in the ventral part of diencephalon including the hypothalamus. Thus, the chromophore is the same between the retinal and pineal visual pigments, but the expression of opsins is different between the retina and pineal complex, which probably reflects the different function of each organ.

We investigated the effects of castration on the development of lymphoid organs (bursa of Fabricius, thymus, and spleen) in the Japanese quail during 4–8 weeks of age under a long photoperiod (16L:8D) and the effect of testosterone implantation on the involution of the lymphoid organs under long (16L:8D) and short (8L:16D) photoperiods. Under 16L:8D, the bursa of Fabricius and thymus in intact quail grew rapidly and reached a peak at 6 weeks of age and regressed thereafter. In contrast, development of the lymphoid orgas in castrated quail was well correlated with the body growth. Testosterone treatment induced a significant reduction in relative bursal weight to body weight at 6 weeks of age under 16L:8D and 8 weeks of age under 16L:8D and 8L:16D, in relative thymus weight at 6 weeks of age under 16L:8D and 8L:16D, and in relative spleen weight at 6 weeks of age under 8L:16D. Thus, we conclude that gonadal hormones play an important role in the development and involution of lymphoid organs.

Several neurotoxins are known which destroy some specific retinal component or other link in the visual pathway. We have employed such reagents to induce blindness in chicks, in order to explore the role of vision in the development of light-induced avian glaucoma (LIAG) and/or lid-suture myopia (LSM). Chicks made pharmacologically blind with formoguanamine failed to develop LSM. Under LIAG conditions, increased eye weight and global enlargement did not occur, but the characteristic anterior segment changes were seen. Thus LIAG globe enlargement, and LSM axial lengthening, appear to be vision-driven, but anterior segment changes are probably separately controlled. The retinal neurotoxin kainic acid rendered chicks behaviorally blind in the eye into which it was injected intravitrially, but this failed to prevent LIAG changes in either anterior segment or growth of the globe. Chicks reared under LSM conditions, and treated with kainic acid were not different from untreated controls, in that they developed globe enlargement in spite of their pharmacologically-induced blindness. Preliminary trials with quisqualic acid, another retinal neurotoxin, indicate that this agent, like kainic acid, cannot prevent LIAG eye enlargement. Several quis-treated eyes developed phthisis bulbi however, and thus could not be included among those assessed for eye weight and dimensional measurements.

SUMMARY In the pineal organ, two types of ganglion cell exhibit antagonistic chromatic responses to UV and green light, and achromatic responses to visible light. In this study, we histologically characterized UV-sensitive photoreceptor cells that contain a unique non-visual UV pigment, lamprey parapinopsin, in order to elucidate the neural network that is associated with antagonistic chromatic responses. These characteristics were compared with those of lamprey rhodopsin-containing cells, most of which are involved in achromatic responses. RT-PCR analysis revealed that lamprey parapinopsin was expressed in the pineal organ but not in the retina, unlike lamprey rhodopsin,which was expressed in both. Lamprey parapinopsin and lamprey rhodopsin were immunohistochemically localized in the dorsal and ventral regions of the pineal organ, respectively. The two pigments were localized in distinct photoreceptor cells throughout the pineal organ, namely the dorsal and ventral regions as well as the peripheral region, which corresponds to the dorso-ventral border region. The ratio of the number of lamprey parapinopsin-containing cells to lamprey rhodopsin-containing cells around the peripheral region was higher than in the central region. Electron-microscopic analysis revealed that lamprey parapinopsin-containing dorsal cells have outer segments and synaptic ribbons similar to those of ventral photoreceptor cells. However, unlike lamprey rhodopsin-containing cells, lamprey parapinopsin-containing cells connected with each other in a wide area of dorsal and peripheral portions and made direct contact with ganglion cells,mainly in the peripheral portion. These results suggest that UV light information captured by lamprey parapinopsin-containing photoreceptor cells is converged and directly transmitted to chromatic-type ganglion cells in the peripheral region to generate antagonistic chromatic responses.

Lower vertebrates can detect UV light with the pineal complex independently of eyes. Electrophysiological studies, together with chromophore extraction analysis, have suggested that the underlying pigment in the lamprey pineal exhibits a bistable nature, that is, reversible photoreaction by UV and visible light, which is never achieved by known UV pigments. Here we addressed the molecular identification of the pineal UV receptor. Our results showed that the long-hypothesized pigment is a lamprey homologue of parapinopsin, which exhibits an absorption maximum at 370 nm, in the UV region. UV light causes cis - trans isomerization of its retinal 2 chromophore, forming a stable photoproduct having an absorption maximum at 515 nm, in the green region. The photoproduct reverts to the original pigment upon visible light absorption, showing photoregeneration of the pigment. In situ hybridization showed that parapinopsin is selectively expressed in the cells located in the dorsal region of the pineal organ. We successfully obtained the hyperpolarizing responses with a maximum sensitivity of ≈380 nm from the photoreceptor cells at the dorsal region, in which the outer segment was clearly stained with anti-parapinopsin antibody. These results demonstrated that parapinopsin is the pineal UV pigment having photointerconvertible two stable states. The bistable nature of the parapinopsin can account for the photorecovery of the pineal UV sensitivity by background green light in the lamprey. Furthermore, we isolated the parapinopsin homologues from fish and frog pineal complexes that exhibit UV sensitivity, suggesting that parapinopsin is a common molecular basis for pineal UV reception in the vertebrate.

Up to now the regulatory mechanisms, which govern the concentrations of neurosteroids in the brain, are unclear. Seasonal breeders may serve as excellent models to understand physiological changes in neurosteroid levels and their regulatory mechanisms. The present study first investigated immunohistochemically the localization of cytochrome p450 side-chain cleavage enzyme (p450scc) and 3beta-hydroxysteroid dehydrogenase/delta(5)-delta(4)-isomerase (3betaHSD) in the brain of the newt Cynops pyrrhogaster, a seasonally breeding amphibian. Both p450scc- and 3betaHSD-like immunoreactive cells were restricted to the preoptic area. Seasonal changes in neurosteroid concentrations were then examined using adult males. Pregnenolone concentrations in the brain showed marked changes during annual breeding cycle and a maximal level in August, independent of the plasma steroid levels which were all low throughout the year. Progesterone concentrations in the brain, which were lower than pregnenolone levels, also showed peaks in April and August. In contrast, the pregnenolone sulfate level was low and its change was less pronounced. To clarify environmental factors that induce seasonal changes in neurosteroid levels, adult males were further subjected to different photoperiods and ambient temperatures for 5 weeks. Both pregnenolone and progesterone concentrations in the brain were significantly higher in the long day (LD) group than in the short day (SD) group, whereas no significant effects of different ambient temperatures on neurosteroid levels were detected. These results suggest that the newt brain possesses steroidogenic enzymes p450scc and 3betaHSD and exhibits seasonal changes in the pregnenolone and progesterone concentrations. Photoperiod may be a more important environmental factor than temperature for the regulation of neurosteroid levels in the brain.

We investigated circadian ocular rhythms in the Japanese quail, Coturnix coturnix japonica. The birds were placed under light-dark cycles (LD 12∶12), constant light (LL) and constant darkness (DD), and the retinas were dissected out at four-hour intervals throughout 24 h. Following measurements were performed. (1) Melatonin content in the retina was measured by radioimmunoassay. It was low in light and several folds higher in darkness under LD 12∶12. The rhythm continued in DD, but disappeared in LL. (2) Mitotic figures in the corneal epithelium were counted. Similar rhythms to the melatonin content were observed in the corneal mitotic rate with a slight phase delay. (3) The retinas were fixed at 4-h intervals and immunostained with anti-bovine rhodopsin serum and anti-chicken iodopsin monoclonal antibodies. The outer segments of photoreceptor cells were stained intensively throughout 24 h in LD 12∶12, LL and DD. In contrast, the stainability of the locus close to the outer limiting membrane where the Golgi apparatus exists changed diurnally. Scores showing the ratio of cells with positive staining indicated high values from 4 h after the onset of light to the beginning of dark phase under LD 12∶12. The values were high throughout 24 h in LL and intermediate or low in DD. (4) To investigate the effect of melatonin on the corneal mitotic rate and visual pigments at the Golgi region, melatonin was injected into one eye and saline into the contralateral eye. Melatonin induced a phase advance in the corneal mitotic rate under LD 12∶12, but did not induce a rhythm under LL. The ratio of photoreceptor cells with positive staining to anti-visual pigment antibodies at the Golgi region was not affected by melatonin injection.

The effects of artificial photoperiod and temperature on testicular FSH binding and plasma FSH levels were studied in adult male Djungarian hamsters. In Exp I, hamsters were transferred to long day (LD) photoperiods (16-h light, 8-h dark) after 8 weeks of adaptation in short day (SD) photoperiods (8-h light, 16-h dark), but the ambient temperature was maintained at 25 C throughout the experiments. A marked increase in the total FSH binding per two testes occurred between 10 and 47 days after transfer to LD, a change that was accompanied by testicular growth. Binding of FSH per testicular weight decreased during the same period. Scatchard plot analyses of the parameters indicated that LD decreased both the concentration of FSH binding sites and the equilibrium dissociation constant (Kd). Plasma FSH levels increased between 10 and 47 days after transfer to LD. In contrast, when hamsters reared under LD for 12 weeks were transferred to SD (Exp II), FSH binding per unit weight basis increased 19 weeks after transfer to SD, but the total binding per two testes decreased markedly. In Exp III, sexually mature male hamsters were subjected to different ambient temperature and photoperiods. There were no significant effects of different ambient temperatures on the testicular weight and testicular FSH binding in animals exposed for 8 weeks to either LD or SD. However, plasma FSH levels of hamsters maintained at 25 C under LD was significantly higher than FSH levels at 7 C under LD. A similar effect of temperature on plasma FSH levels was observed in hamsters under SD. The present study indicates that photoperiod is a more important environmental factor than temperature for the regulation of FSH receptor in the Djungarian hamster.

The effects of artificial photoperiod, temperature, and long-term testosterone treatment on testicular luteinizing hormone (LH) binding were studied in adult male Djungarian hamsters. In hamsters transferred to long-day (LD; 16 hr light, 8 hr dark) photoperiod 8 weeks after adaptation in short-day (SD; 8 hr light, 16 hr dark) photoperiod of 25 degrees C, testicular growth was associated with an increase in the total LH binding per two testes and a decrease in LH binding per unit testicular weight. Plasma testosterone levels reached a peak 47 days after transfer to LD and tended to decrease thereafter, while the testes continued growing. In contrast, when hamsters reared under LD conditions at 25 degrees C for 12 weeks were transferred to SD, testicular regression was associated with a decrease in plasma testosterone and the total LH binding per two testes and an increase in LH binding per unit testicular weight. A significant decrease in LH binding per unit weight compared to SD controls was observed in those hamsters exposed to SD with continuous testosterone treatment. The testosterone treatment tended to induce decrease in the total LH binding. Scatchard plot analyses of the binding suggested that changes in LH binding were due to changes in the number of binding sites. When sexually mature male hamsters were subjected for 8 weeks to two different ambient temperatures (7 degrees C and 25 degrees C) and photoperiods (LD and SD), the difference between the two temperature groups was statistically not significant regarding the weights of testes, epididymides, and prostates; plasma testosterone levels; and LH binding in either LD or SD group. These results suggest that photoperiod is a more important environmental factor than temperature for the regulation of testicular activity and LH receptors and that testosterone reduces the number of LH receptors per unit testicular weight in adult male Djungarian hamsters.

Mitotic rhythms were investigated in the chick corneal epithelium under various lighting regimens. Day‐old chicks were subjected to LD 14:10 (14 hr‐light: 10 hr‐darkness) for 2 weeks and the number of mitotic cells were counted in the central and peripheral regions of the cornea. The mitotic activity was high in darkness and low in light, and higher activity in the central region than in the peripheral region was observed. Anticipatory sharp rise in mitotic activity was observed just after light off. When chicks were reared in LD 12:12 (light on 06:00–18:00) and in inverted LD 12:12 (light on 18:00–06:00), the phase of the rhythm in normal LD 12:12 was different by 180° from that in inverted LD 12:12. When chicks were transferred to continuous light or continuous darkness after 2 weeks in LD 14:10, the mitotic rhythm disappeared in continuous light, but it continued in continuous darkness, suggesting a circadian nature of the rhythm. Two‐day old chicks, which were given only one LD cycle, also sh...

The involvement of the retina in avian lid suture myopia was investigated by use of formoguanamine (FG), which induces blindness in chicks, characterized by damage to the retinal pigment epithelium and photoreceptor layers. In control chicks reared under a diurnal lighting schedule of 12L/12D, unilateral eyelid suture at 3 days of age induced a typical lid suture myopia response on the operated side (eye enlargement and bulging cornea) by 4 wks. of age. On the other hand, in FG-treated blind chicks also reared under 12L/12D, there was no difference in eye parameters, between sutured and non-sutured eyes. All globe parameters measured were very similar in FG-treated and control non-sutured chicks. Corneal diameter and anterior chamber depth in the eyes of FG-treated chicks were significantly smaller than in non-sutured control eyes.

The influence of the photo period, of pinealectomy and of bilateral enucleation on several endocrine organ weights of Japanese quail (Coturnix cotumix japonica) have been explored. At 5 weeks after hatching, pituitary, adrenal and gonadal weights were higher, and thyroid weight was lower, in birds maintained under continuous light (24L/OD) than in those held under a short phoroperiod (8L/16D) for 3 weeks. Blinded birds did not differ from sham-pinealectomized ones in these endocrine parameters. Pinealectomy abolished the photoperiod-dependent responses of the adrenal and thyroid, while pituitary and gonadal weights were unaffected. At 6 weeks after hatching, the previously observed thyroid response was not as pronounced, and pinealectomy no longer altered the adrenal response to the photoperiod. Thus, the photoperiod and the pineal appear to be important for maturation of several endocrine glands, and the eyes do not seem to be necessary for these photo-endocrine responses in Japanese quail. (Endocrinolog...

Hypophysectomy of Japanese quailsubsequently reared under continuous light had noeffect on either pineal weight or pinealhydroxyindole-O-methyl transferase (HIOMT) activity. The gonads showed marked atrophy followinghypophysectomy. Adrenal weight was somewhatreduced but this was significant only in 10-week-oldmale quail. Thyroid weight was not affected byhypophysectomy. All hypophysectomized birdsshowed conspicuous molting. Melatonin administration (0.1, 1.0, 10, or 100µg/day for 14 days) did not affect testis weight ofadult quail under 16L/8D, 12L/12D or 8L/16Dphotoperiods. (Endocrinology 94: 1735, 1974)

Domestic chicks reared under continuous dim light developed the eye enlargement and suppressed corneal growth characteristic of light-induced avian glaucoma (LIAG) and dim light buphthalmos (DLB). Administered corticosterone moderated these effects on both the globe of the eye and the cornea. The anti-adrenal agent Metyrapone had no discernable effects on the globe parameters of the eye, although the cornea was somewhat enlarged and the anterior chamber deeper than in controls. Mitotic rate in the corneal epithelium, and adrenal and testis weight, were more sensitive indicators, showing that both the hormone and its antagonist induced changes in these experimental subjects.