Binding protein for 5 alpha-dihydrotestosterone in mouse submandibular gland.

The changes in the levels of the binding protein for 5 alpha-dihydrotestosterone in cytoplasmic extract of the submandibular glands during development were compared in male and female mice using a DEAE-cellulose filter assay. The binding protein was first detectable 5 days after birth in both sexes, at a time coincident with androgen-independent cytodifferentiation of the convoluted tubular cells in the submadibular gland. The level of the binding protein in female mice was maintained at 5 pmol/mg protein after birth, whereas in males it began to decrease from 3 weeks after birth with inccrease in serum testosterone, becoming much less than a quarter of the level in females or immature mice by 4 weeks after birth. However, after castration, the level of detectable binding protein in mature male mice increased within 7 days to the same level as that in females or immature mice. This suggests that the low binding capacity for exogenous hormone in mature male mice is due to occupancy of the binding sites by endogenous hormone.     

Binding protein for 5α-dihydrotestosterone in mouse submandibular gland

The changes in the levels of the binding protein for 5α-dihydrotestosterone in cytoplasmic extract of the submandibular glands during development were compared in male and female mice using a DEAE-cellulose filter assay. The binding protein was first detectable 5 days after birth in both sexes, at a time coincident with androgen-independent cytodifferentiation of the convoluted tubular cells in the submandibular gland. The level of the binding protein in female mice was maintained at 5 pmol/mg protein after birth, whereas in males it began to decrease from 3 weeks after birth with increase in serum testosterone, becoming much less than a quarter of the level in females or immature mice by 4 weeks after birth. However, after castration, the level of detectable binding protein in mature male mice increased within 7 days to the same level as that in females or immature mice. This suggests that the low binding capacity for exogenous hormone in mature male mice is due to occupancy of the binding sites by endogenous hormone.     

Sexual dimorphism in the energetics of reproduction and growth of North Sea plaice, Pleuronectes platessa L.

The chemical composition and energy content of North Sea plaice during the spawning period were examined in mature males and females and in immature fish, to study differences in the allocation of energy over reproduction and somatic growth between the sexes. At the beginning of the spawning period mature males and females had equal dry weights of lipid that were 70% higher than in immatures. Protein content in mature males was equal to that in immatures but was 23 % higher in mature females. Immature males and females did not differ in chemical composition. At the end of the spawning period, spent and immature fish had equal lipid contents, but protein content in spent females was 10% lower than in spent males, and 17% lower than in immatures. Gross energy content of the body decreased by 44% (65·2 to 36·3 J cm^-3) in mature females, 27% (55·0 to 40·OJ cm^-3) in mature males, and 9% (48·7 to 44·2J cm^-3) in immatures. Energy content of plaice eggs was estimated at 6·60 kJ per 1000 eggs. Reproductive investment was estimated from the energy loss during the spawning period and included the energy of sex products and spawning metabolism. Somatic growth comprised the annual increase in energy content of fish. The pattern of energy allocation over reproduction and somatic growth differed between males and females. Males started their reproduction at a smaller length and a younger age and allocated a higher proportion of the available energy into reproduction than females. Available energy resources for somatic growth and reproduction (surplus production) were equal between the sexes up to a length of about 30 cm. Beyond this length male surplus production levelled off whereas female surplus production continued to increase. The differences in surplus production and the allocation patterns are discussed. For female plaice the energy allocated into egg production was estimated as between 48 and 64% of the total amount of energy lost during spawning. The remaining energy is used for metabolism during the spawning period, yielding an estimate of the metabolic rate of mature females of between 6·4 and 9·1 kJ day^-1. A maximum estimate of the metabolic rate of mature males was 7·4 kJ day^-1.     

Patterns of affiliation among immature rhesus monkeys (Macaca mulatta)

The affiliative interaction patterns of the immature members of a group of rhesus monkeys at the Yerkes Regional Primate Research Center reflected a strong bias toward matrilineal kin, although this effect was modified by age and sex variables. Association with kin decreased with age, particularly for males. Juvenile males showed less of a kin bias in their behavior than did juvenile females, especially for grooming. Juvenile males also exhibited a preference for interaction with other males. The diminished association with kin and the same-sex bias may be reinforced in adolescence as adult males begin to aggressively target adolescent males involved in agonistic encounters with females or immatures. Adolescent males did not decrease their levels of social interaction relative to those of adolescent females; however, these males preferentially associated with other males (predominantly their own age-sex class) and specifically avoided females and younger animals, both kin and nonkin. Avoidance may diminish conflicts with females or immatures which could result from association, thereby decreasing the potential for selective aggressive interference by adult males. Juvenile and adolescent females maintained strong ties with their kin and preferentially associated with other females and immatures. The breadth of interaction of females with other females may facilitate the establishment of dominance relationships as females mature. Familiarity and predictability may also decrease the necessity of more severe agonistic interaction.     

Platelet serotonin levels and gonadal hormones in rats

The role of gonadal hormones in the control of platelet serotonin levels was studied by evaluating the effect of sexual maturation in rats of both sexes and the time-course of changes following gonadectomy performed either prepubertally or on sexually mature animals. In males, platelet serotonin levels remained fairly stable during sexual maturation as well as during the whole postgonadectomy period monitored (four months). In females, somewhat higher values of platelet serotonin levels in adult than in sexually immature animals were found (9%, p less than 0.001, N = 34). A slight decrease of platelet serotonin (10-18%, p less than 0.05) was observed following ovariectomy of sexually mature females, but it was of transient nature. When females were ovariectomized prepubertally a tendency towards permanently lower platelet serotonin levels was noticed. These results suggest that gonadal hormones have no major role in the control of platelet serotonin levels in rats, although a subtle hormonal modulation of this platelet variable in females may exist.     

Prognosis for clinical pregnancy and birth after transferring embryos derived from a cohort of incompletely mature oocytes at retrieval time

The purpose of this retrospective study was to establish a prognosis for implantation, pregnancy and live birth rates in stimulated IVF cycles after transferring embryos derived from: 1/ retrieved immature oocytes that matured overnight in vitro (late mature group: LM); 2/ retrieved immature oocytes that matured overnight in vitro and were added to the embryos derived from retrieved mature oocytes (mixed embryos group: MX); and 3/ retrieved mature oocytes (mature group: M). The obtained implantation, clinical pregnancy and live birth rates for the LM group were: 5.6%, 11.4%, 11.4%; for the MX group were: 4.2%, 14.6%, 11.6%; and for the M group were: 14.6%, 45.2% and 33.3%, respectively. These measurements were significantly lower p<0.05 for the LM and MX groups in comparison to the M group. The number of oocytes retrieved and the number of embryos transferred were the lowest (p<0.001-0.05) for the LM group. It is concluded, that the retrieved immature oocytes are able to mature during overnight culture in vitro, be fertilized and provide developmentally competent embryos with the prognosis of 11% for the successful delivery.     

Parental care does not vary with age‐dependent plumage in male Saffron Finches Sicalis flaveola

The status signalling hypothesis states that conspicuous male plumage varies among males and serves as an honest signal of male quality and competitive ability. We expected immature‐plumaged males of the Saffron Finch Sicalis flaveola to feed their incubating mates and nestlings and remove faecal sacs at lower rates than those of mature‐plumaged males. We also predicted that females paired with immature‐plumaged males would compensate for their mates’ lower contribution. We found no differences in either feeding rates or sanitation rates between immature‐ and mature‐plumaged males. Similarly, females mated to immature‐ and mature‐plumaged males fed nestlings at equivalent rates. Apparently, male plumage colour and age are not reliable signals of the ability of a male Saffron Finch to provide for his mate and offspring.     

Hormone-protein interactions and functional activity of the adrenal cortex during adaptation to pressure chamber hypoxia

Blood plasma and adrenals of rats subjected to the exposure of deep pressure-chamber hypoxia are studied. The method of high-performance liquid chromatography is used to determine the content of corticosterone and deoxycorticosterone as well as the binding ability of transcortin relative to hydrocortisone and corticosterone before and after ectomy of endogenic hormones. It is shown that hyperactivation of adrenals occurs already the first 20 min of the experiment, which is preserved during the whole experiment lowering, to some extent, by 150, 240 min. The binding ability of transcortin considerably lowers in the acute phase of stress and after the prolonged hypoxic exposure due to a 1.5-1.9-fold decrease in the number of the binding sites in the protein. The equilibrium redistribution is revealed in the plasma between free corticosterone and corticosterone bound to transcortin at the different stages of the hypoxic exposure.     

Hypoosmoregulation in an anadromous teleost: influence of sex and maturation

Salinity tolerance and hypoosmoregulatory ability of anadromous brook trout (Salvelinus fontinalis) were investigated in relation to sex and state of maturation. Seawater survival of mature males was significantly poorer than that of females or immature males. Lowered salinity tolerance of adult males became acute during the autumn photoperiod (normal spawning period) when the gonadosomatic index was high. Plasma [Cl-], [Mg2+], osmolarity and hematocrit were significantly higher in mature males after transfer to seawater, relative to mature females. It is postulated that reduced adult male hypoosmoregulatory ability explains skewed sex ratios in anadromous brook trout populations and may limit the extent of brook trout anadromy.     

Relative ventricular weight of wild Atlantic salmon parr in relation to sex, gonad maturation and migratory activity

Relative ventricular weight (RVW, ventricular weight/body weight · 100) was measured for five groups of Atlantic salmon parr from the Girnock Burn in Scotland. The mean RVW was: mature males, 0.087; immature resident males, 0.054; immature resident females, 0.056; immature migrant males, 0.056; immature migrant females, 0.053. For a group of mature male parr from the R. Nith, Galloway, Scotland, the mean RVW was 0.108. There were no significant differences in the RVW between groups of immature fish. The RVW of each group of mature male parr was significantly greater than those of each, group of immature parr. Condition indices (weight/length³) were closely similar between all groups of parr. The functional significance of plasticity in ventricular weight is discussed in relation to life histories of Atlantic salmon.     

Context and Development of Sexual Behavior of Wild Bonobos (Pan paniscus) at Wamba, Zaire

I studied sexual behavior of immature bonobos (Pan paniscus) in a wild group living at Wamba, Zaire, with special reference to its development. Even immature individuals under 1 year old performed sexual behavior. Sexual behavior occurred in almost all age–sex combinations, except between immature and mature females. Based on analyses of behavioral pattern and context, I classified sexual behavior involving immature individuals into three categories. (1) Genital contact between immature individuals was observed during play, and was performed by males more frequently than by females. This sexual behavior shared many traits with that of other great apes. (2) Copulation-like genital contact was observed between immature males and mature females. Its frequency increased with the immature male's age; it developed into copulation in adulthood. (3) Genital contact used to regulate interindividual relationships. This behavior, which is unique to bonobos, was absent among infants. It developed between late juvenile and early adolescent periods in association with changes in social circumstances.     

Infrapopulations of Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Cavisomidae) in the rabbitfish Siganus rivulatus (Teleostei, Siganidae) from the Saudi coast of the Red Sea

In infrapopulations of helminth parasites, density-dependent effects, through some form of intra- and interspecific competition, play an important role in shaping and regulating the infrapopulations. The mechanisms responsible for these processes have often been observed in laboratory studies and rarely studied under natural conditions. Here, 24 natural infrapopulations (77-447 individuals) of the acanthocephalan Sclerocollum saudii Al-Jahdali, 2010 from the fish Siganus rivulatus consisted of cystacanths, newly excysted juveniles, immature and mature worms, distributed in a well-defined fundamental niche (anterior 60% of the intestine). Each of these stages exhibited a significantly different longitudinal distribution within this niche. In small infrapopulations, cystacanths and newly excysted juveniles were found in the sixth 10% of the intestine, immature worms in the fifth 10% and mature worms in the anterior 40% of the intestine. However, their proportions followed a clear ascending order in each infrapopulation, and the female-male ratios of both immature and mature worms were distinctly female-biased. In large infrapopulations, mature worms existed partially in the site of immature ones, where a differential mortality among immature females was constantly observed. However, the proportions of immature worms increased significantly and those of mature worms decreased significantly, the mean lengths of immature and mature females decreased dramatically and the female-male ratios were distinctly male-biased. The mean sizes of immature and mature males seemed stable through all infrapopulations. The distribution of mature males and females suggests intense male-male competition for access to females, and reveals that larger females are copulated prior to the smaller ones. The results are statistically significant and suggest that infrapopulation self-regulation is through density-dependent mechanisms, in which immature females may play a key role.     

Platelet-activating factor induces the expression of early pregnancy factor activity in female mice

When synthetic platelet-activating factor (PAF, 1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) was injected into mature female mice during dioestrus, pro-oestrus or oestrus, it induced the expression of early pregnancy factor (EPF) activity in the sera of these animals within 1 h of injection. The sera of similarly injected males, metoestrous or immature females did not display any EPF activity. The results suggest that embryo-derived PAF may be the ovum factor responsible for triggering the generation of serum EPF activity during the preimplantation stages of pregnancy.     

Effect of sex hormones on plasma T-kininogen in the rat

The influence of sex hormones on rat plasma T-kininogen concentration was examined. The level of T-kininogen in the post-pubertal female rat is about 3-times that of the male animal. Female rats castrated as adults or 15 days after birth, had low T-kininogen concentrations, near those of male rats. In contrast, castration of mature or immature male animals induced no change in T-kininogen. Treatment of castrated female or male rats with 17 alpha-ethinylestradiol significantly increased the T-kininogen level, whereas administration of testosterone or progesterone had no effect. The influence of estrogen was specific for T-kininogen, since plasma HMW kininogen concentration was the same in male and female rats and was not affected by castration or sex hormone treatment. T-kininogen concentration was not significantly changed in pregnant rat between the 12th and the 20th day of pregnancy, but increased after parturition. It was high in the newborn rat at birth and then decreased similarly over the next 3 weeks in males and females. It continued to decrease in the males, reaching the level of the adult rat, but it increased in the female from 3-4 weeks of age and reached the adult level at about 6-8 weeks. These data indicate that natural estrogens have a physiological influence on the plasma level of T-kininogen in female rats whereas testosterone had no effect on either male or castrated female rats. HMW kininogen is not physiologically dependent on sex hormones.     

Luteinizing hormone secretion from the quail pituitary in vitro

An enzymatically dispersed pituitary preparation from Japanese quail (Coturnix coturnix) was used to study the dynamics of gonadotropin release. After an 18-h incubation, the cells were challenged with different luteinizing hormone-releasing hormones (LHRH) for 90 min. Using pituitary cells from mature males, mammalian and chicken LHRH I (Gln8-LHRH) had approximately equal luteinizing hormone (LH)-releasing activity whereas chicken LHRH II (His5, Trp7, Tyr8-LHRH) was 8-9 times more potent. The LHRH agonist (Trp6, Pro9-NEt-LHRH) had 15 times greater potency than chicken LHRH I. Pre-incubation with an LHRH antagonist (D-Phe2, D-Trp6-LHRH) significantly suppressed LH release. Acid extracts of median eminence released LH from pituitary cells, extracts from short-day and long-day males had equal activity, while tissue extracts from castrated males had significantly greater LH-releasing activity. Pituitary cells from sexually immature males released LH in response to chicken LHRH I in a similar profile to cells from mature males. These data indicate that the quail LHRH receptor in the male recognizes several different molecular species of LHRH and the response to LHRH is comparable between short- and long-day males. Pituitary cells from ovulating females were variably sensitive to LHRH peptides, possibly due to changes in pituitary sensitivity during the ovulatory cycle. Pituitary cells from immature females did not release LH in response to chicken LHRH I. However, pituitary cells from immature females photostimulated for 1 wk displayed a response to chicken LHRH I and II similar to that of pituitary cells from males.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sexual maturation in the black seabream Mylio macrocephalus Teleostei,Sparidae: changes in pituitary gonadotropes,hepatocytes and related biochemical constituents in liver and serum

Summary The black seabream, Mylio macrocephalus, exhibits the phenomenon of sex segregation. Immature fish are developing hermaphrodites, and show a considerable overlap with mature males in their body weights. Mature females tend to be the heaviest group. Fish can be classified into immature, developing and mature groups, with a further division into definitive males or females in the two latter groups. The developing groups still have bisexual gonads, whereas mature males have testes with only a comparatively inconspicuous portion of ovarian tissue, and mature females possess ovaries with vitellogenic oocytes and a greatly regressed testicular component. In the present study, monthly samples were collected over a 3-year period, and changes in pituitary gonadotropes and liver tissue studied by light, and electron microscopy. Seasonal changes in serum constituents were also studied by biochemical techniques.Gonadotropes increased in number and became hypertrophied during sexual maturation, showing an enhanced cytoplasmic vacuolation and degranulation of alcian blue- and periodic acid-Schiff-positive material. The levels of various biochemical constituents in the liver and serum of developing fish tended to be intermediate between those recorded in the immature and mature groups. In mature fish, the serum levels of glucose, sodium and calcium were elevated, but hepatic glycogen content was less than the developing group, and hepatocytes contained activated mitochondria. The seasonal changes in pituitary cytology, hepatic ultrastructure and serum constituents, could be correlated with the metabolic adaptations to sexual maturation.     

Body composition and gut length of<Emphasis Type="Italic">Akodon azarae</Emphasis> (Muridae: Sigmodontinae): relationship with energetic requirements

Akodon azarae (J. Fischer, 1829) is a small omnivorous murid rodent that lives in environments with seasonal fluctuations of food. Seasonal variation in its body composition and gut length, in relation to reproductive status, was studied. Physical Condition Index (PCI) and body composition showed seasonal differences, however, there were no differences in intestine length. The PCI was higher for both mature males and reproductive females compared to immature males and non-reproductive females. Lipid, protein and ash content showed differences in relation to reproductive status. The results suggest thatA. azarae meets the additional costs of pregnancy and lactation by increasing energy intake, without relying on reserves.     

Sexual size dimorphism, growth and maturity of the Japanese fluvial sculpin,Cottus pollux (large egg type), in the Inabe River, Mie prefecture, central Japan

The population structure of the Japanese fluvial sculpin,Cottus pollux (large egg type), in the upper reaches of the Inabe River, Mie Prefecture, central Japan, was investigated by a mark-and-recapture method from July 1989 to January 1991. Breeding of the species occurred from mid February to early May, peaking from mid February to late March. The mean size of mature males observed in March 1990 was significantly larger than that of females, showing apparent sexual size dimorphism. Data analysis of the growth of 1658 marked individuals revealed that the species matured at 2 years of age in both sexes. Whereas 1 year old males reached ca. 50–70 mm SL, females were less than 50 mm SL at the same age, size dimorphism already being apparent. Immature males exhibited higher growth rates than females during their first and second years, some of the former outstripping mature males of the preceding year class in total length. After attaining sexual maturity, both males and females grew mainly from July to December, with no significant differences in mean growth rate between them. Sexual size dimorphism of the species seems to be attributable to different growth rates between the sexes during their immature stage.     

Relationship between social interactions and sexual maturation in female Saguinus oedipus oedipus

4 female Saguinus oedipus oedipus were paired with strange, unrelated males while 5 remained in their natal family groups. A comparison of the frequency of selected social interactions involving these females when sexually immature versus mature was made. The frequency of sexual and affiliative interactions in male-female pairs was basically unchanged by the female's maturation. Mother-daughter interactions were also not changed in a consistent fashion by the daughters' maturation. Females with strange, unrelated males, either alone or as part of their natal group, displayed increases in marking behavior in association with sexual maturation.     

Construction and test of an artificial uterus for ex situ development of shark embryos

An artificial uterus (AU) was constructed from clear and opaque acrylic and life-support and monitoring systems were attached. The dwarf ornate wobbegong shark (Orectolobus ornatus) was used to test the AU because recent research has shown that during pregnancy the uterine fluid composition changes with mid- to late-term embryos immersed in seawater. An artificial uterine fluid comprising filtered, autoclaved seawater was placed in the AU. Eight, sexually mature female O. ornatus were captured from the wild and held in captivity. Subsequent ultrasound examinations confirmed pregnancy in three of these females. Six late-term embryos (three males and three females) were removed surgically from one euthanized female and placed in the AU. Their condition was monitored for 18 days before "birth" on September 26, 2008. The subsequent survival and growth of the AU pups was compared with naturally born wobbegong pups in captivity over a 140-day monitoring period. The development in the AU did not have detrimental effects as there was no postpartum mortality and there were marked increases in total length and weight that did not differ significantly between the two groups.