scholarly journals Sexual dimorphism in thyroid function and type 1 iodothyronine deiodinase activity in pre-pubertal and adult rats

2007 ◽  
Vol 192 (1) ◽  
pp. 121-130 ◽  
Author(s):  
Michelle P Marassi ◽  
Rodrigo S Fortunato ◽  
Alba C Matos da Silva ◽  
Valmara S Pereira ◽  
Denise P Carvalho ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Adult Male ◽  
Gonadal Hormones ◽  
Adult Males ◽  
Adult Rats ◽  
Iodothyronine Deiodinase ◽  
Adult Females ◽  
Serum T3 ◽  
Serum Tsh

Iodothyronine deiodinase activities are regulated by sex steroids; however, the mechanisms underlying the reported sexual dimorphism are poorly defined. In the present report, we aimed to investigate whether type 1 deiodinase (D1) sexual dimorphism exists early in sexual development by studying pre-pubertal male (Pm) and female (Pf) rats, as well as adult controls (C) and gonadectomized male and females rats. Adult male Wistar rats were studied 21 days after orchiectomy (Tex), and adult females were studied 21 days after ovariectomy (Ovx), and after estradiol benzoate (Eb) replacement. Serum total triiodothyronine (T3) was higher in pre-pubertal (P) rats than in the matching adults, with no difference between genders, although in adult males T3 was significantly lower than in females. There were no sex or age differences in serum total T4. Serum TSH in pre-pubertal (P) rats was within the adult female range, and both were significantly lower than in adult males. D1 activity in liver was greater in Pm than in Pf. In adult females, liver D1 activity was lower, while in adult males it was higher than in P rats. The same pattern of D1 activity was found in kidney. In thyroid and pituitary, D1 activity was similar in Pm, Pf, and adult females, which were all significantly lower than in the adult male. There were no differences in serum T3 and T4 between C and Tex males, but serum TSH was significantly decreased in Tex rats. Hepatic and renal D1 activities were lower in Tex than in C, but no changes were detected in thyroid and pituitary. In Ovx females, T3 was significantly lower than in the C group. Serum T4 was significantly decreased by estradiol replacement therapy in Ovx rats, in both doses used, whereas TSH was unchanged. Eb replacement increased liver and thyroid D1 activity, but in the kidney, only the highest estradiol dose promoted a significant D1 increase. In conclusion, in males, hepatic and renal D1 activity appears to be significantly influenced by gonadal hormones, in contrast to females, in which only exogenous Eb treatment stimulated D1 activity. The comparison between pre-pubertal and adult rats suggests that serum T3 is not the main regulator of D1 activity, and other factors, besides T3 and gonadal hormones, can modulate D1 activity during murine maturation.

scholarly journals Inhibition of pituitary type 2 deiodinase by reverse triiodothyronine does not alter thyroxine-induced inhibition of thyrotropin secretion in hypothyroid rats

2005 ◽  
Vol 153 (3) ◽  
pp. 429-434 ◽  
Author(s):  
P Cettour-Rose ◽  
T J Visser ◽  
A G Burger ◽  
F Rohner-Jeanrenaud
Keyword(s):  
Specific Inhibitor ◽  
Adult Rats ◽  
Reverse T3 ◽  
Brown Adipose ◽  
Tsh Secretion ◽  
Serum T3 ◽  
Serum T4 ◽  
Serum Tsh ◽  
Tsh Levels

Objectives: Intrapituitary triiodothyronine (T3) production plays a pivotal role in the control of TSH secretion. Its production is increased in the presence of decreased serum thyroxine (T4) concentrations and the enzyme responsible, deiodinase type 2 (D2), is highest in hypothyroidism. In order to document the role of this enzyme in adult rats we developed an experimental model that inhibited this enzyme using the specific inhibitor, reverse T3 (rT3). Methods: Hypothyroidism was induced with propylthiouracil (PTU; 0.025 g/l in drinking water) which in addition blocked deiodinase type 1 (D1) activity, responsible for the rapid clearance of rT3 in vivo. During the last 7 days of the experiment, the hypothyroid rats were injected (s.c.) for 4 days with 0.4 or 0.8 nmol T4 per 100 g body weight (bw) per day. For the last 3 days, the same amount of T4 was infused via s.c. minipumps. In additional groups, 25 nmol rT3/100 g bw per day were added to the 3-day infusion of T4. Results: Infusion of 0.4 nmol T4/100 g bw per day did not affect the high serum TSH levels, 0.8 nmol T4/100 g bw per day decreased them to 57% of the hypothyroid values. The infusions of rT3 inhibited D2 activity in all organs where it was measured: the pituitary, brain cortex and brown adipose tissue (BAT). In the pituitary, the activity was 27%, to less than 15% of the activity in hypothyroidism. Despite that, serum TSH levels did not increase, serum T4 concentrations did not change and the changes in serum T3 were minimal. Conclusions: We conclude that in partly hypothyroid rats, a 3-day inhibition of D2 activity, without concomitant change in serum T4 and minimal changes in serum T3 levels, is not able to upregulate TSH secretion and we postulate that this may be a reflection of absent or only minimal changes in circulating T3 concentrations.

Sexual dimorphism in Upper Palaeolithic hand stencils

Antiquity ◽  
2006 ◽  
Vol 80 (308) ◽  
pp. 390-404 ◽  
Author(s):  
Dean R. Snow
Keyword(s):  
Sexual Dimorphism ◽  
Adult Male ◽  
Human Hand ◽  
Upper Palaeolithic ◽  
Men And Women ◽  
Sexual Roles ◽  
Adult Females ◽  
Palaeolithic Art ◽  
Cave Art

Sexual roles in deep prehistory are among the most intriguing puzzles still to solve. Here the author shows how men and women can be distinguished by scientific measurement in the prints and stencils of the human hand that occur widely in Upper Palaeolithic art. Six hand stencils from four French caves are attributed to four adult females, an adult male, and a sub-adult male. Here we take a step closer to showing that both sexes are engaged in cave art and whatever dreams and rituals it implies.

scholarly journals The Diet and Sexual Differences of the Caspian Bent-Toed Gecko,Tenuidactylus caspius(Squamata: Gekkonidae), in Northern Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Vida Hojati ◽  
Reza Babaei Savasari
Keyword(s):  
Sexual Dimorphism ◽  
Culex Pipiens ◽  
Tail Length ◽  
Adult Males ◽  
Northern Iran ◽  
Widespread Distribution ◽  
Adult Females ◽  
Significant Difference ◽  
Males And Females ◽  
Prey Items

The Caspian bent-toed gecko,Tenuidactylus caspius, is one of the most common nocturnal lizards of Iran with widespread distribution especially in the northern provinces. This research was done in order to study the diet and sexual dimorphism of this species in Sari County from 5 May to 20 October. During this research, 40 specimens of them including 20 males and 20 females were studied for diet and 140 specimens including 70 adult males and 70 adult females were studied for sexual dimorphism. Prey items identified were insects that belong to 15 species of 8 families and 6 orders. The most common prey items wereCulex pipiensandMusca domestica. There is no significant difference between diets of males and females. Results show that the adult males in addition of having the apparent femoral and preanal pores are heavier than females and have larger body, head, and tail length.

scholarly journals Gender Differences in the Effect of Prenatal Methamphetamine Exposure and Challenge Dose of Other Drugs on Behavior of Adult Rats

2013 ◽  
pp. S99-S108 ◽  
Author(s):  
R. ŠLAMBEROVÁ ◽  
E. MACÚCHOVÁ ◽  
K. NOHEJLOVÁ-DEYKUN ◽  
B. SCHUTOVÁ ◽  
L. HRUBÁ ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Adult Male ◽  
Gonadal Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Prenatally Exposed ◽  
Challenge Dose ◽  
Adult Rats ◽  
Male And Female ◽  
Male And Female Rats

The aim of the present study was to compare the response to acute application of several drugs in adult male and female rats prenatally exposed to methamphetamine (MA). Spontaneous locomotor activity and exploratory behavior of adult male and female rats prenatally exposed to MA (5 mg/kg) or saline were tested in a Laboras apparatus (Metris B.V., Netherlands) for 1 h. Challenge dose of the examined drug [amphetamine – 5 mg/kg; cocaine – 5mg/kg; MDMA (3,4-methylenedioxymethamphetamine) – 5 mg/kg; morphine – 5 mg/kg; THC (delta9-tetrahydrocannabinol) – 2 mg/kg] or saline was injected prior to testing. Our data demonstrate that prenatal MA exposure did not affect behavior in male rats with cocaine or morphine treatment, but increased locomotion and exploration in females. Application of amphetamine and MDMA in adulthood increased activity in both sexes, while cocaine and THC only in female rats. Morphine, on the other hand, decreased the activity in the Laboras test in both sexes. As far as sex and estrous cycle is concerned, the present study shows that males were generally less active than females and also females in proestrus-estrus phase of the estrous cycle were more active than females in diestrus. In conclusion, the present study shows that the prenatal MA exposure does not induce general sensitization but affects the sensitivity to drugs dependently to mechanism of drug action and with respect to gonadal hormones.

scholarly journals Patterns of pair formation and mating in an ectoparasitic caligid copepod Lepeophtheirus salmonis (Krøyer 1837): implications for its sensory and mating biology

1998 ◽  
Vol 353 (1369) ◽  
pp. 753-764 ◽  
Author(s):  
M. Q. Hull ◽  
A. W. Pike ◽  
A. J. Mordue ◽  
G. H. Rae
Keyword(s):  
Adult Male ◽  
Host Finding ◽  
Pair Formation ◽  
Adult Males ◽  
Unmated Female ◽  
Female Ratio ◽  
Genital Complex ◽  
Adult Females ◽  
Mating Biology ◽  
Reproductive Events

Non–invasive observations of single cohort and manipulated populations of the sealouse on laboratory–maintained salmon established the sequence of reproductive events and mating. Protandry occurs with adult male emergence synchronized with pre–adult II female emergence, the stage at which most pair formation and pre–copular guarding takes place. Male competence for pair formation and mating was achieved within 24 h of the final moult and pairing occurred according to the preference hierarchy, virgin adult females greater than pre–adult II females much greater than pre–adult I females. This hierarchy broke down when the adult male to unmated female ratio increased rapidly. Males mated successfully not only with newly moulted adult females, but also with older virgin females in which enlargement of the genital complex and premature extrusion of egg strings had occurred. Multiple mating by adult males was demonstrated and may be widespread. Significant inter–host transfer was also demonstrated. Adult males were more mobile than adult females and showed significantly more inter–host transfer. Ablation of the distal tip of the antennules significantly reduced the success of host–finding, pair formation and males' mating.

Wounding in Hawaiian monk seals (Monachus schauinslandi)

1993 ◽  
Vol 71 (3) ◽  
pp. 458-468 ◽  
Author(s):  
Lisa M. Hiruki ◽  
William G. Gilmartin ◽  
Brenda L. Becker ◽  
Ian Stirling
Keyword(s):  
Coral Reef ◽  
Adult Male ◽  
Marine Debris ◽  
Adult Males ◽  
Monachus Schauinslandi ◽  
Aggressive Interactions ◽  
Size Classes ◽  
Adult Females ◽  
Northwestern Hawaiian Islands ◽  
Monk Seals

Injuries observed on endangered Hawaiian monk seals (Monachus schauinslandi) at Laysan Island and French Frigate Shoals in the northwestern Hawaiian Islands in 1988 and 1989 were classified into six major types, based on the source of the wounds: mating attempts by adult male monk seals; nonmating aggressive interactions with other seals; attacks by large sharks; attacks by cookiecutter sharks (Isistius brasiliensis); contact with coral reef or debris; and entanglement in netting or marine debris. At both locations, injuries inflicted by adult male seals during mobbing incidents, in which many males attempt to mate with one seal, were seen more frequently than other types of injuries in 1988 and 1989. Injury data from 1982 – 1987 at Laysan Island and from 1985 – 1989 at French Frigate Shoals were used to compare the distribution of mating injuries inflicted by adult males and injuries inflicted by large sharks over size and sex classes of seals. Mating injuries caused by adult male seals were seen primarily on adult females but were also seen on seals in other size classes. Mating injuries inflicted by adult males occurred earlier in the year and with greater frequency at Laysan Island than at French Frigate Shoals. Injuries inflicted by large sharks were observed more often on adult male seals than on seals in other size classes at Laysan Island; however, no such difference was seen among size classes at French Frigate Shoals.

Dispersion of adult male Peromyscus leucopus in relation to female reproductive status

1989 ◽  
Vol 67 (4) ◽  
pp. 1047-1052 ◽  
Author(s):  
Xuhua Xia ◽  
John S. Millar
Keyword(s):  
Mating System ◽  
Adult Male ◽  
Early Pregnancy ◽  
Peromyscus Leucopus ◽  
Natural Populations ◽  
Negative Relationship ◽  
Late Pregnancy ◽  
Adult Males ◽  
Adult Females ◽  
Female Reproductive Status

We studied dispersion of adult male Peromyscus leucopus in relation to the stage of pregnancy of adult females in natural populations monitored with Longworth live traps. Because postpartum mating is common in P. leucopus and days to parturition measures how far a female is from her next mating, we predicted that a female in early pregnancy (many days to parturition) would have fewer adult males in her neighbourhood than a female in late pregnancy (few days to parturition). Number of adult males caught within 30 m of each adult female was recorded and number of days to parturition for each female was obtained by bringing females back to the laboratory and allowing them to give birth. A negative relationship was found between number of adult males in a female's neighbourhood and days to parturition of the female (r = −0.419, p < 0.01), with the latter accounting for 8.8% of the variance in the former. These results support the hypothesis of a promiscuous mating system in P. leucopus.

A new species of stone loach (Teleostei: Nemacheilidae: Schistura) from Arunachal Pradesh, India

Zootaxa ◽  
2019 ◽  
Vol 4551 (1) ◽  
pp. 40
Author(s):  
HRISHIKESH CHOUDHURY ◽  
ABHINIT DEY ◽  
RATUL CH. BHARALI ◽  
DANDADHAR SARMA ◽  
WAIKHOM VISHWANATH
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Colour Pattern ◽  
Adult Males ◽  
Arunachal Pradesh ◽  
Stone Loach ◽  
Adult Females ◽  
North Bank ◽  
Brahmaputra Basin ◽  
A New Species

Schistura rebuw, new species, is described from the Kameng River, a north-bank tributary of the Brahmaputra, Arunachal Pradesh, India. The new species is easily distinguished from all known congeners in the Brahmaputra basin by its unique sexual dimorphism, specifically a suborbital slit in adult females, and a suborbital flap in adult males; and a colour pattern of 10–11 blackish bars on a greyish-beige body, the pre-dorsal bars mostly broken or incomplete, coalescing dorsally in a more or less alternate fashion. 

scholarly journals The Roles of DNA Methyltransferases 1 (DNMT1) in Regulating Sexual Dimorphism in the Cotton Mealybug, Phenacoccus solenopsis

Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 121 ◽  
Author(s):  
Mohamed A.A. Omar ◽  
Meizhen Li ◽  
Feiling Liu ◽  
Kang He ◽  
Muhammad Qasim ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Dna Methyltransferase ◽  
Dna Methyltransferases ◽  
Invasive Pest ◽  
Adult Males ◽  
Small Interfering Rnas ◽  
Phenacoccus Solenopsis ◽  
Adult Females ◽  
Cotton Mealybug ◽  
Gravid Females

The cotton mealybug, Phenacoccus solenopsis, is an invasive pest that can cause massive damage to many host plants of agricultural importance. P. solenopsis is highly polyphagous, and shows extreme sexual dimorphism between males and females. The functions of DNA methyltransferase (DNMT) enzymes in the cotton mealybug have not been well studied. Here, we carried out an investigation of DNMTs in cotton mealybug to study their roles in sexual dimorphism. We found that the cotton mealybug has two copies of PsDnmt1, but Dnmt3 is absent. We then amplified the full-length cDNAs of PsDnmt1A (2225 bp) and PsDnmt1B (2862 bp) using rapid amplification cDNA ends (RACE). Quantitative reverse transcriptase PCR shows that both PsDnmt1A and PsDnmt1B are highly expressed in adult males, while the expression of PsDnmt1B is 30-fold higher in gravid females than in virgin females. We knocked down PsDnmt1A and PsDnmt1B with small interfering RNAs (siRNAs), and both genes were successfully down-regulated after 24 h or 72 h in adult females and pupa (t-test, p < 0.05). Down-regulating the expression of these two DNMT genes led to offspring lethality and abnormal body color in adult females. Furthermore, the silencing of PsDnmt1B induced abnormal wing development in emerged adult males. Our results provide evidence that PsDnmt1 plays a crucial role in regulating sexual dimorphism in the cotton mealybug.

scholarly journals Morphological variation of Philodryas patagoniensis (Girard, 1858) (Serpentes, Dipsadidae) from Brazil, based on the study of pholidosis, coloration and morphometric features

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Rafaella Vallim Gouveia ◽  
Iara Alves Novelli ◽  
Fabiano Matos Vieira ◽  
Bernadete Maria de Sousa
Keyword(s):  
Sexual Dimorphism ◽  
Analysis Of Variance ◽  
Morphological Variation ◽  
Tail Length ◽  
Head Length ◽  
Adult Males ◽  
Adult Females ◽  
Morphometric Features ◽  
The Relationship

Abstract The current study aimed to verify the relationship between the patterns of coloration, the morphometrical features and pholidosis of specimens of Philodryas patagoniensis from Brazil, with the sexual dimorphism of this species. We studied specimens of P. patagoniensis deposited in several herpetological collections from Brazil. A total of 355 specimens were analyzed, of these 145 were males (87 adults and 58 juveniles) and 210 were females (134 adults and 76 juveniles). Adult specimens exhibit sexual dimorphism in snout-vent length, tail length, head length, number of ventral shields, and number of subcaudal shields. The analysis of variance showed that the adult females are significantly longer than adult males, both at snout-vent length and tail length. Females have a greater number of ventral shields (138-210) than males (151-200). The specimens studied also exhibit two distinct patterns of coloration unrelated to geographical or sexual variations.

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