SEX DIFFERENCES IN GROWTH OF GUINEA-PIGS AND THEIR MODIFICATION BY NEONATAL GONADECTOMY AND PRENATALLY ADMINISTERED ANDROGEN

1973 ◽  
Vol 58 (1) ◽  
pp. 11-19 ◽  
Author(s):  
A. K. SLOB ◽  
R. W. GOY ◽  
J. J. van der WERFF ten BOSCH
Keyword(s):  
Growth Rate ◽  
Guinea Pigs ◽  
Testosterone Propionate ◽  
Growth Curves ◽  
Postnatal Growth ◽  
Normal Female ◽  
Stimulatory Action ◽  
Prenatal Growth ◽  
Males And Females ◽  
The Difference

SUMMARY One group of animals received androgen prenatally, by daily s.c. injections of 5 mg testosterone propionate (TP) to the doe on days 24 to 41 inclusive of pregnancy, while a second group remained untreated. Some animals of each group were gonadectomized on the day of birth (= day 1) or on day 2. Weight at birth served as a measure of prenatal growth. Comparisons were made between animals born in litters of identical size. Postnatal growth was studied by weighing the animals at 5-day intervals until the age of 130 days. Comparisons were made between groups of animals that were matched for their weights at birth. At birth males from TP-treated mothers were heavier than their sisters and heavier than control males. After birth, control males grew at faster rates than control females. This difference was not affected by neonatal gonadectomy, but from pubertal age onward the difference decreased and gonadectomized males and females were similar in growth. Female pseudohermaphrodites (from TP-treated mothers), both intact and neonatally ovariectomized, had growth curves similar to those of appropriate male controls at prepubertal ages; at postpubertal ages they were not significantly different from their female counterparts. It is concluded that the sex difference in the rate of prepubertal growth is determined by the absence or presence of androgens before birth, and that the difference in postpubertal growth rate is caused by the stimulatory action of the testes and inhibitory action of the ovaries. It was further found that normal female guinea-pigs have a secondary spurt in growth rate, some time after puberty, whereas in males this was much less clear.

scholarly journals Growth curve of Atlantoscia floridana (van Name) (Crustacea, Isopoda, Philosciidae) from a Brazilian Restinga Forest

2004 ◽  
Vol 21 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Paula Beatriz Araujo ◽  
Georgina Bond-Buckup
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Urban Areas ◽  
Field Data ◽  
Growth Curves ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Differential Growth ◽  
Estimate Life Expectancy ◽  
Males And Females

The terrestrial isopod Atlantoscia floridana (van Name, 1940) occurs from the U.S.A. (Florida) to Brazil and Argentina. In the southernmost Brazilian State, Rio Grande do Sul, the species is recorded in many localities, in urban and in non-urban areas. The growth curve of Atlantoscia floridana based on field data is presented. The specimens were sampled from April, 2000 to October, 2001 at the Reserva Biológica do Lami (RBL), Rio Grande do Sul. Captured individuals were sexed and had their cephalothorax width measured, with the data analyzed with von Bertalanffy's model. The growth curves for males and females are described, respectively, by the equations: Wt = 1.303 [1 - e-0.00941 (t + 50.37)] and Wt = 1.682 [1 - e-0.00575 (t + 59.13)]. The curves showed differential growth between sexes, where females reach a higher Wµ with a slower growth rate. Based on the growth curves it was also possible to estimate life expectancy for males and females.

scholarly journals Prenatal and postnatal growth: An ultrasound and clinical investigation

2016 ◽  
Vol 6 ◽  
pp. 147-153
Author(s):  
Shahista Parveen ◽  
Rohan Mascarenhas ◽  
Akhter Husain ◽  
Devadas Acharya
Keyword(s):  
Growth Rate ◽  
Assessment Tool ◽  
Clinical Investigation ◽  
Normal Pregnancy ◽  
Postnatal Growth ◽  
Fetal Life ◽  
Prenatal Growth ◽  
Facial Development ◽  
The Relationship ◽  
Growth Assessment

Background Understanding facial development requires sound knowledge of growth at different stages. Although studies in the past have established the relationship between prenatal and postnatal growth, little research has been done using noninvasive ultrasound. The purpose of this study is to evaluate correlation between prenatal and postnatal growths using ultrasound as a fetal growth assessment tool. Study Settings: It is a hospital-based study where prenatal growth is measured at different intervals of gestational period and compared with the growth at birth. Materials and Methods: Ten subjects with normal pregnancy were studied using ultrasound. Cephalocaudal growth gradient, body proportions of the fetus were assessed and compared at different stages. Growth was also evaluated at birth and compared with the predicted growth. Results The growth rate of estimated fetal weight is at maximum between the 28th and 32nd week of the fetal life (P ≤ 0.001). The growth rate of head circumference, occipitofrontal diameter, and femur length is maximum between the 20th and 28th week of the fetal life (P < 0.001). Cephalocaudal growth gradient decreases with increased age of the fetus. Conclusions Prenatal growth is correlated with postnatal growth. Ultrasound can be used as a tool for the measurement and prediction of prenatal and postnatal growths.

scholarly journals Stimulation of the corpora lutea of the rat by means of progesterone and testosterone

1937 ◽  
Vol 124 (836) ◽  
pp. 362-368 ◽  
Keyword(s):  
Guinea Pigs ◽  
Rhesus Monkeys ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Corpora Lutea ◽  
Normal Female ◽  
Once Daily ◽  
Black And White ◽  
White Rats ◽  
Stimulation Of

The administration of progestin or progesterone inhibits oestrus in normal female experimental animals and leads to the cessation of follicular growth (Papanicolaou 1926, working on guinea-pigs; Gley 1928, on rats; Corner 1935, on monkeys). Active testicular extracts or testosterone have a similar effect (Ihrke and D’Amour 1931; Lendle 1931; and Robson 1936, working on rats; Zuckerman 1937, on rhesus monkeys). There is evidence that a phase of luteal activity occurs whenever the ripening of follicles is inhibited (see Evans 1928; Weichert 1930, amongst others), and it was therefore of interest to enquire whether or not luteinization of the ovaries is also an effect of the administration of progesterone and testosterone to normally cyclic female rats. Previous reports on this question are negative. Papanicolaou (1926) observed degenerative changes in the ovaries of guinea-pigs in which several successive oestrous cycles had been suppressed by means of progestin. Selye, Browne and Collip (1936) injected six rats with 4 mg. of progesterone for 12 days, and at the close of the experiment found that neither recent corpora lutea nor mature follicles were present in the ovaries. Albino and black and white rats were used. All injections were given once daily and subcutaneously. Oestrone was administered in aqueous solution, and both progesterone and testosterone propionate in oil. At the end of each experiment the uterus and one of the ovaries were fixed in Bouin’s fluid, and after sectioning, stained with haematoxylin and eosin, the ovary being sectioned serially. The second ovary of each animal was fixed in Flemming’s chrome-osmium fluid with acetic acid, and prepared to show osmicated fats according to the technique described by Deanesly (1930). In certain cases, noted below, the uterus was traumatized by the method of Shelesnyak (1933α) (a modification of that of Long and Evans), in order to produce deciduomata.

scholarly journals The birth weight of rabbits born after heterospermic insemination

1960 ◽  
Vol 1 (1) ◽  
pp. 39-49 ◽  
Author(s):  
R. A. Beatty
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Previous Experiment ◽  
Gestation Period ◽  
Enhancement Effect ◽  
Average Birth Weight ◽  
Prenatal Growth ◽  
Mature Weight ◽  
The Difference ◽  
Object Of Study

1. Two rabbit sires were used for insemination of sixty-eight females. Insemination was either homospermic (one sire at a time) or heterospermic (mixed semen from the two sires). Each offspring could be traced to its sire by genetic marks. The sires differed in weight and were known to give offspring differing in mature weight and named Large and Small offspring. The object of study was the birth weight of these offspring in logarithmic transformation.2. After heterospermic insemination, there was no evidence of any real ‘heterospermic vigour’ in the average birth weight of the litter as a whole.3. After heterospermic insemination, the difference in birth weight between the two kinds of offspring was accentuated (enhancement effect). This confirms a previous experiment.4. The enhancement effect is ascribed to competition among embryos. It is not attributable to postulated changes in the gestation period. It appears to arise from an increase in the birth weight of Large offspring, together with a possible decrease in the birth weight of Small offspring. These changes in birth weight are attributable to changes in prenatal growth rate.5. The bearing of this work on Russian experiments with heterospermie insemination is discussed.

Sex difference in histamine metabolism in rats

1959 ◽  
Vol 197 (6) ◽  
pp. 1258-1260 ◽  
Author(s):  
K. S. Kim
Keyword(s):  
Sex Difference ◽  
Testosterone Propionate ◽  
Female Rats ◽  
Free Form ◽  
Total Output ◽  
Normal Female ◽  
Histamine Metabolism ◽  
Endogenous Histamine ◽  
Male And Female Rats ◽  
The Difference

The pattern of endogenous histamine excretion in the urine of male and female rats has been studied. The major sex difference is that females put out approximately 25 times more free histamine than males. This difference in free histamine output accounts for the difference in total output. Castration increased free histamine output in males, but ovariectomy or combined ovariectomy and hysterectomy have no effect on output in females. The castration effect appears in 2–5 weeks. One milligram of testosterone propionate when injected subcutaneously suppresses the output of free histamine in castrated rats, but not in normal female rats. There are also sex differences in the handling of exogenous histamine. Castrated and female rats excrete a larger proportion of exogenous histamine in the free form. This indicates that a difference in handling rather than in rate of production may account wholly or partly for the observed sex difference in endogenous histamine output.

Growth rate estimates for New Zealand Rig (Mustelus lenticulatus)

1992 ◽  
Vol 43 (5) ◽  
pp. 1157 ◽  
Author(s):  
MP Francis ◽  
RICC Francis
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
Frequency Analysis ◽  
Growth Rates ◽  
Growth Curves ◽  
Combined Effects ◽  
Length Frequency ◽  
Total Length ◽  
Males And Females ◽  
Length Frequency Analysis

Growth rate estimates were obtained for New Zealand rig (Mustelus lenticulatus) by analysing length frequency and tag-recapture data. Rig (0+) sampled by set-net in Porirua and Pauatahanui Inlets grew from about 25-30 cm total length at birth to 46-49 cm at age of about 6 months. Samples of juvenile and adult rig trawled in Pegasus Bay and Hauraki Gulf suffered from under-representation of large adults, probably because of escapement. Growth curves derived from length-frequency analysis indicated that Pegasus Bay males matured at 5.0 years and had a minimum longevity of 12 years. Hauraki Gulf males and females matured at 3.7 and 4.7 years, respectively. Growth rates and ages at maturity fell within the ranges reported for other Mustelus species. Tagging data for South Island rig suggested that females grew faster than males. However, growth rate estimates from length-frequency analysis were 2.7-3.3 times greater than estimates from tagging data, probably because the latter were biased by the combined effects of tagging on growth and set-net mesh selectivity.

Effects of stimulated high altitude on the growth rate of albino guinea pigs

1965 ◽  
Vol 20 (5) ◽  
pp. 1022-1025 ◽  
Author(s):  
L. Delaquerrière-Richardson ◽  
Susanna Forbes ◽  
Enrique Valdivia
Keyword(s):  
Growth Rate ◽  
High Altitude ◽  
Sea Level ◽  
Perinatal Mortality ◽  
Guinea Pigs ◽  
Postnatal Growth ◽  
High Altitudes

Two different groups of pregnant albino guinea pigs were exposed continuously, during the second half of gestation, to simulated high altitudes of 12,000 ft in the first experiment and of 14,000–16,500 ft in the second. Pregnancy was significantly shorter in the second experiment than at sea level. Birth weights were lower than in controls in both experiments, more so in the second. Perinatal mortality was markedly increased, reaching 42% in the second experiment. All animals were kept at 12,000 ft after birth. Postnatal growth was slower than at sea level, except in females born at 12,000 ft, whose weights did not vary significantly from those of controls. hypoxia; perinatal mortality Submitted on November 10, 1964

On the Nature of Hereditary Size Limitation

1929 ◽  
Vol 6 (3) ◽  
pp. 293-310
Author(s):  
ROBERT CUMMING ROBB
Keyword(s):  
Growth Rate ◽  
Growth Curves ◽  
F1 Hybrids ◽  
Adult Size ◽  
Mendelian Segregation ◽  
Size Limitation ◽  
Two Factors ◽  
Animal Growth ◽  
The Difference ◽  
Nutritional Disturbances

1. New data are recorded for the post-natal growth in body weight of Flemish Giant and diminutive Polish rabbits, and of their F1 hybrids. 2. The specific or percentage growth rate is identical for Flemish, hybrid and Polish males from the time of birth to the onset of puberty. 3. The process of development in the Flemish Giants differs from that of the Polish in that the latter are but half as large at the time of birth. The fact of their shorter gestation period (thirty days in contrast to thirty-one) does not entirely account for the difference observed. Hence the existence of some growth depressant acting upon the young of the small race (or growth accelerator acting upon the young of the large race) in utero may be surmised. 4. Hybrid animals from Giant does by Polish bucks and from the reciprocal cross are not so much affected, being at birth almost as large as the pure bred Giants. Accordingly the growth curves of hybrids and Giants closely approximate each other until the fourth month of post-natal existence. 5. During the fourth month Polish and hybrid animals undergo a more rapid retardation of growth than do the Flemish Giants. Their growth rate values, which have been indistinguishable hitherto, diverge at this time. The lesser size of the Polish adult can be ascribed to two factors, one effective during the placental period and the other at a more advanced age. In the last analysis both may have a common cause. 6. The growth curves of these rabbits have been described by the equation for autocatalysis sponsored by Crozier. These examples show the most extensive approximation to the theoretical of any mammalian data to which this equation has been hitherto applied. 7. In the equation two velocity constants are employed, each having its own magnitude in the large and small races. Although the hybrid offspring are intermediate in adult size their growth curves do not lie midwav between those of their parents. Prior to its inflection point the hybrid curve is similar in magnitude to that of the Flemish Giants, thereafter the early retardation of growth resembles that of the Polish. Moreover, the hybrid values of K1 and K2 are not both intermediate between those of the parents--K1 being practically identical to that characteristic of the Polish parent. These facts invite extended investigation since they portend that in the inheritance of growth regulating processes there occurs a Mendelian segregation of unit characters. 8. Two small deviations of the observed from the theoretical values are consistently present and have been subject to analysis. The first growth aberration accompanies the circulatory, thermal and nutritional disturbances inevitably associated with birth. The second or juvenile deviation is concurrent with an endocrine reorganisation, in which the thymus, testes and suprarenal cortex are concerned. 9. The natal and juvenile growth retardations tend to divide the animal growth curve into three periods (one pre-natal and two post-natal) which have been dignified by the name of "growth cycles." Such a "cycle" does not represent an increase of the percentage growth rate but merely an increase of velocity due to the enlargement of a greater mass at a lesser rate. If one admit the validity of these observations the existence of disturbing factors is an adequate explanation of the three apparent cycles. Therefore it is maintained that to postulate a succession of autocatalysed master reactions is superfluous as well as inadequate. 10. Brody's conception of "five or more abruptly delimited periods of uniform increase" is not sustained by this material. 11. The adherence of these data to an integral curve descriptive of autocatalysis does not assure the validity of an analogy but the utility of that hypothesis has been enlarged.

SEX DIFFERENCES IN LENGTH OF GESTATION IN MAMMALS

1956 ◽  
Vol 13 (3) ◽  
pp. 309-318 ◽  
Author(s):  
THOMAS McKEOWN ◽  
BRIAN MacMAHON
Keyword(s):  
Sex Differences ◽  
Guinea Pig ◽  
Sex Difference ◽  
Litter Size ◽  
Alternative Explanation ◽  
Prenatal Growth ◽  
Males And Females ◽  
The Difference ◽  
Duration Of Gestation ◽  
Length Of Gestation

Observations on length of gestation of males and females are presented for man, the guinea-pig, sheep, pig and rabbit; from the literature, data are also available for the cow, horse, camel and goat. Pregnancy is longer for males than for females in the cow, horse and possibly the sheep and camel; it is longer for females than for males in man and possibly the guinea-pig. No definite conclusion is reached about the pig and rabbit, in which litter-size is normally large, or about the goat, in which the number of observations on record is small. The sex differences in length of gestation are reflected in the sex ratios of offspring born after different periods of gestation, and in the percentage distribution of the sexes by duration of gestation. The difference in length of gestation can be attributed to a sex difference in foetal weight in man, but not in the guinea-pig or in species such as the cow, in which gestation is longer for males than for females. It is suggested that in the cow the longer male gestation may be due to the fact that the proportion of males conceived is higher if mating takes place early, rather than late, in heat. (The only alternative explanation is a sex difference, attributable to something other than weight of foetus, in the period between fertilization and birth.) In man the earlier birth of males is apparently due to their greater weight, attributable wholly or in part to a sex difference in rate of prenatal growth. This observation does not exclude the possibility that in man, as in the cow, the proportion of males conceived is higher if mating occurs early in the cycle, since the method of recording length of gestation (from onset of menstruation) gives no information about time of mating.

Effects of Water Circulation on the Growth of Quahaugs and Oysters

1949 ◽  
Vol 7c (9) ◽  
pp. 545-551 ◽  
Author(s):  
C. J. Kerswill
Keyword(s):  
Growth Rate ◽  
Water Flow ◽  
Prince Edward Island ◽  
Growth Curves ◽  
Growing Season ◽  
Water Circulation ◽  
The Difference

Holding quahaugs and oysters through a growing season in circulation-controlled trays in Bideford river, Prince Edward Island, showed that they react differently to decreased water circulation. Quahaugs grow in proportion to the extent of circulation and can survive and grow significantly when there is very little water flow. Oysters are affected little by moderately reduced circulation but grow little and may die when the circulation is much reduced. Growth of quahaugs in beds is seriously reduced by eel-grass growing on the beds, and also by eel-grass merely in the vicinity of the beds. Growth curves are given for quahaugs in natural up-river and down-river beds and the difference in growth rate is attributed to difference in water circulation.

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