Hormonal specificity and activation of sexual behavior in male zebra finches

Castrated zebra finches receiving one of six hormone treatments were given three weekly tests with different females and their sexual behavior was contrasted with that of two control groups consisting of intact or castrated males given implants of cholesterol. The six hormone treatments were: two aromatizable androgens, testosterone (T) and androstenedione (AE); two nonaromatizable androgens, androsterone (AN) and dihydrotestosterone (DHT); an estrogen, estradiol (E); or a combination of E + DHT. Half the males receiving DHT received the 5α-isomer, half received the 5β-isomer. Castration significantly reduced the proportion of males which courted females, total courtship displays, high-intensity courtship displays, beak wiping activity, and significantly increased the latencies to show these behaviors compared to intact males. Castrated males never attempted to mount a female. All of these measures of courtship and copulatory behavior were restored to normal levels only by treatments providing both estrogenic and α-androgenic metabolites (i.e., T, AE, E + αDHT). AE was clearly the most effective of these, raising behavior significantly above normal on several measures. AN treatment was more effective than αDHT on all measures and not significantly different from intact birds on some. Treatment with E, αDHT, βDHT, or E + βDHT was totally ineffective. Surprisingly, females only solicited males whose hormone treatments provided estrogenic metabolites. Not only did they solicit males given aromatizable androgens, which showed high rates of courtship activity, they also solicited males given E or E + βDHT, some of which never even courted. Castration and hormone treatment also affected body and syringeal weight, but in opposite directions. Castration increased body weight while decreasing syringeal weight. Hormone treatments providing α-androgenic metabolites decreased body weight and increased syrinx weight. Treatments supplying estrogen as well were slightly more effective.     

Social spacing in the mormyrid fish Gnathonemus petersii (Pisces): A multisensory approach

The sensory basis of group cohesion in the weak-electric fish Gnathonemus petersii was investigated in a circular tank with groups of four fish each, interacting through a wide-meshed plastic screen with intact or operated conspecifics, or with other stimulus objects. We confined these stimuli to one or two peripheral holding compartments. The response measures were obtained from the free swimming fish and included (1) the time the fish spent together as a group, (2) the time they spent in front of the holding compartments, (3) the circular distribution of the fish's positions, and (4) the mean nearest neighbour distances. Under empty compartment conditions, four different groups were tested, consisting of either (1) intact, electrically active fish, or (2) electrically ‘silent’ fish (with their electric organ surgically rendered inoperative), or (3) blind, or (4) ‘silent’ and blind animals. The loss of either sensory modality, vision or feedback from electric organ discharge, led to changes of comparable size, decreasing the time spent as a group and increasing the mean nearest neighbour distance. In fish lacking both modalities, group cohesion was further impaired. With stimuli present in one or both holding compartments, the strength of social attraction depended on the nature of the stimulus: the more intact stimulus conspecifics were present, the more densely did the fish group in front of the stimulus compartment. ‘Wired-in’ electric organ discharges (simulating waveform and intensity) and electrically ‘silent’ fish were equally attractive, but only half as attractive as intact fish. Blind free swimming fish aggregated with intact and also with ‘silent’ conspecifics. Under dim light conditions, group cohesion was predominantly, though not exclusively, affected by electrosensory feedback from the electric organ discharge and visual input. Mechanical and olfactory cues may also be involved.     

Effects of androgen on scent marking and aggressive behavior of neonatally bulbectomized female Mongolian gerbils (Meriones unguiculatus)

Female gerbils were bilaterally bulbectomized, unilaterally bulbectomized or sham-operated at 2 days of age (Birth DAY = 0). As adults, the occurrence of scent marking and aggressive behavior was measured prior to and following administration of either testosterone propionate (TP) or oil. TP-treated sham operates showed increased scent marking; bilaterally bulbectomized and unilaterally bulbectomized females treated with TP did not. The display of aggressiveness increased for all females following TP. Neonatally bulbectomized animals treated with TP, however, were the most aggressive. Although androgen augments these species-typical response patterns, it seems dependent upon the integrity of the olfactory bulbs.     

A comparative study of the bactericidal activity of horseshoe crab (Limulus polyphemus) hemolymph and vertebrate serum

This paper describes a partially heat-labile, naturally occurring bactericidal factor in cell-free hemolymph preparations obtained from Limulus polyphemus. This bactericidal activity has been shown to be directed against two Gram-negative bacteria, Escherichia coli and Klebsiella pneumoniae, whereas it had no effect on the Gram-positive bacteria tested, Micrococcus lysodeikticus and Staphylococcus aureus. Maximal bactericidal activity of this factor was observed at 30°C and pH 6.0. Since complement and antibody are required for antimicrobial activity in vertebrate sera, the activity of this factor in the presence of various complement inhibitors was assayed. The bactericidal activity of Limulus hemolymph is abolished by treatment with endotoxin; however, other anticomplementary substances were without effect. Limulus amebocyte lysate is known to contain protein which may be precipitated by endotoxin; it is possible that the reduction of bactericidal activity produced by endotoxin treatment may be caused by the denaturation of a bactericidal protein moiety produced by the hemocytes.     

Ovariectomy-induced changes in food motivation in the rat

Following ovariectomy, adult female rats did not increase their food-reinforced bar pressing during 30-min tests, but they responded significantly more frequently for food than did control animals during 2- and 24-hr bar-press tests. Meal pattern data obtained during the 24-hr test demonstrate that ovariectomy increases meal size and decreases meal frequency, although the reduction in the number of meals did not fully compensate for the alteration in meal size. These findings suggest that ovariectomy does not increase the motivation to initiate a meal, but does result in the taking of a larger meal. The implication of these findings to body-weight set-point interpretations of ovarian obesity are briefly discussed.     

Effects of maternal diabetes on the development of carbohydrate metabolizing enzymes in fetal rat liver

Effects of streptozotocin-induced maternal diabetes on fetal hepatic carbohydrate-metabolizing enzyme development and hormonal status has been explored in the rat. Hepatic glycogen synthase a activity of the normal fetus rose to a maximum at 20 days of gestation, then fell prior to parturition. In fetuses of diabetic mothers, this prepartum decline was curtailed, resulting in enhanced synthase a activity and increased glycogen content in fetal livers at term. Elevation in hepatic synthase a in fetuses of diabetic mothers was due, not to altered interconversion between existing synthase a and b, but to equivalent increases in both forms of the enzyme. Both hepatic and free plasma corticosterone levels were elevated in fetuses of diabetic mothers and may be responsible for the enhanced development of total glycogen synthase observed in these fetuses. In normal fetuses hepatic phosphofructokinase and pyruvate kinase activities also rose to maxima at 20 days, then declined prior to term. In fetuses of diabetic mothers pyruvate kinase activity attained higher than normal maximal levels and phosphofructokinase activity fell more gradually, thus resulting in elevations in both enzyme activities at term. Augmentations in these glycolytic enzymes are compatible with hyperinsulinemia observed in fetuses of diabetic mothers. The following conclusions may be drawn from these findings. During late fetal life developmental patterns of rate-limiting hepatic glycogen-synthesizing and glycolytic enzymes are adapted to glucose utilization. In the normal fetus these patterns reverse at term, thereby promoting glucose mobilization, which prepares the fetus for abrupt deprivation of maternal glucose at birth. Maternal diabetes results in retardation of these reversal processes, presumably due to elevations in fetal glucocorticoid and insulin levels. Glycogenolytic and glucogenic capacities are thereby impaired in these fetuses.     

Sexual preferences of male hamsters (Mesocricetus auratus) for conspecifics in different endocrine conditions

The behavioral responses of sexually experienced male hamsters toward a pair of anesthetized conspecifics were investigated. Males spent significantly more time licking, sniffing, and mounting neonatally and adult castrated males than intact males. Adult castrated males receiving oil injections were preferred over castrates receiving exogenous testosterone propionate (TP). Ovariectomized females were preferred over intact males, adult castrated males, or spayed females receiving exogenous TP. It was concluded that the absence of an androgen-dependent factor(s) renders an animal more sexually attractive.     

Immunochemical studies on the combining site of the d-galactose/N-acetyl-d-galactosamine specific lectin from Erythrina cristagalli seeds

The combining site of the Erythrina cristagalli lectin was studied by quantitative precipitin and precipitin inhibition assays. The lectin precipitated best with two fractions of a precursor human ovarian cyst blood group substance with I and i activities. A₁, A₂, B, H, Le^a, and Le^b blood group substances precipitated poorly to moderately and substances of the same blood group activity precipitated to varying extents. These differences are attributable to heterogeneity resulting from incomplete biosynthesis of carbohydrate chains. Specific precipitates with the poorly reactive blood group substances were found to be more soluble than those reacting strongly. Precipitation was minimally affected by EDTA or divalent cations. Among the monosaccharides and glycosides tested for inhibition of precipitation, p-nitrophenyl βdGal was most active and was 10 times more active than methyl βdGal, indicating involvement of hydrophobic contacts in site specificity. Methyl αdGalNAc, p-nitrophenyl αdGalNAc, methyl αdGal, N-acetyl-d-galactosamine, p-nitrophenyl αdGal, methyl βdGal, and p-nitrophenyl βdGalNAc were progressively less active than p-nitrophenyl βdGal. The best disaccharide inhibitor dGalβ1 → 4dGlcNAc was 7.5 times more potent than p-nitrophenyl βdGal. A tetraantennary and triantennary oligosaccharide containing four and three dGalβ1 → 4dGlcNAcβ1 → branches, respectively, were, because of cooperative binding effects, 1.6 and 2.5 times more active than the bi- and monoantennary oligosaccharides, respectively. dGalβ1 → 4dGlcNAcβ1 → 6dGal and dGalβ1 → 4dGlcNAcβ1 → 2dMan had the same activity, being 1.5 times more active than dGalβ1 → 4dGlcNAc, which was 2.6 and 8.5 times more active than dGalβ1 → 3dGlcNAc and dGalβ1 → 3dGlc, respectively. Substitutions by N-acetyl-d-galactos-amine or l-fucose on the d-galactose of inhibitory compounds blocked activity. These results suggest that a hydrophobic interaction with the subterminal sugar is important in the binding and that the specificity of the lectin combining site involves a terminal dGalβ1 → 4dGlcNAc and the β linkage of a third sugar.     

Rat lymphocyte subsets: Cellular requirements for the generation of T-cell growth factor

In this study, the cells producing T-cell growth factor (TCGF) in the rat MLR were characterised with respect to the antigens defined by $\text{W}\text{3}\text{13}\text{,}\text{W}\text{3}\text{25}$, and OX8 monoclonal antibodies. Unfractionated lymphocytes and cells depleted of OX8 positive cells were found to be fully capable of producing TCGF, whereas lymphocytes depleted of $\text{W}\text{3}\text{13}\text{and}\text{W}\text{3}\text{25}$ positive cells had lost this ability. Parallel experiments demonstrated that cells selected by the fluorescence-activated cell sorter for the expression of $\text{W}\text{3}\text{13}\text{and}\text{W}\text{3}\text{25}$ defined antigens were potent producers of TCGF. Further studies suggested a functional role for the antigen defined by $\text{W}\text{3}\text{25}$ antibody because the addition of this antibody to a MLR abrogates TCGF production. These findings suggest that the important immunomodulatory functions of $\text{W}\text{3}\text{25}$ positive lymphocytes could be exercised via the synthesis of essential lymphokines.     

The influence of glucocorticoids during the neonatal period on the development of play-fighting in Norway rat pups

A series of experiments was designed to investigate the influence of glucocorticoids on the development of play-fighting in rat pups. Previously we have found male-typical high levels of play-fighting to depend on the presence of androgens in neonatal life. Here we report that neonatally administered glucocorticoids act to suppress these high levels of play-fighting in males. In Experiment 1, male neonates treated on either Days 1 and 2 or Days 3 and 4 of life with 300 μg of corticosterone play-fought less frequently than did oil-treated animals. Corticosterone treatment on Days 9 and 10 of life had no effect suggesting that there is a “critical period” for the corticosterone effect. Similar corticosterone treatment of female pups did not influence the frequency of play-fighting. In Experiment 2, 300 μg dexamethasone, administered on Days 3 and 4 of life, had an effect in males, comparable to corticosterone. These results suggest that there is a sex-dependent, organizational effect of glucocorticoids on the development of play-fighting in rat pups. Additional experiments showed that corticosterone treatment of males on Days 1 and 2 of life did not affect adult male sexual behavior nor did it affect levels of circulating testosterone measured on Day 3 of life. These results suggest that glucocorticoid inhibition of testosterone secretion cannot account for the effect on play behavior. The possibility that glucocorticoids act directly on neural tissues to counteract testosterone effects is discussed.     

An analysis of sandbathing and grooming in the kangaroo rat (Dipodomys merriami)

The sandbathing and grooming behaviour of ten kangaroo rats (Dipodomys merriami) were recorded on sand and woodchip substrates after periods of 0,1,5 and 10 days without sand. Sandbathing is restricted to the sandy substrate. Grooming occurs on both, but with a higher frequency on sand. Increases in both grooming and sandbathing occur with increasing sand deprivation, but the temporal patterning does not change. D. merriami tends to alternate sandbathing components in contrast to other Dipodomys species. Lipid on the pelage increases noticeably with sand deprivation and decreases during a sandbathing bout; sand appears to be removed from the pelage by shaking and grooming. These findings suggest a three-process system for care of the body surface.     

Prevalence of known mutations and a novel missense mutation (M694K) in the MEFV gene in a population from the Eastern Anatolia Region of Turkey

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent attacks of fever and serositis. Mutations in the Mediterranean fever gene (MEFV) localized on the short arm of chromosome 16 cause FMF. Over 90 MEFV missense/nonsense mutations have been identified so far in FMF patients, mostly in the 10th exon of the gene.