Sex Differences In Body Weight Research Articles

Chlorpropamide-alcohol flush: significance of body weight, sex and serum chlorpropamide level.

Chlorpropamide-alcohol flush (CPAF) tests were carried out in 15 male and 15 female Type 2 diabetics. Twelve subjects were CPAF-positive and 18 were -negative. The two groups did not differ in age or duration of diabetes, but the CPAF-positive subjects weighed less (mean difference 13 kg) and had higher plasma chlorpropamide levels. There was a negative correlation between plasma chlorpropamide and body weight, and a positive correlation between plasma chlorpropamide and the increase in facial skin temperature. Females had higher plasma chlorpropamide, a greater skin temperature increase and lower body weight than males; there were 11 females and only 1 male amongst the 12 CPAF-positive subjects. The findings confirm that plasma chlorpropamide is a major determinant of the CPAF reaction and also show that body weight strongly influences the chlorpropamide level and, consequently, the outcome of the CPAF test. The sex difference in body weight probably accounts for most, if not all, of the sex difference in the incidence of the CPAF.

Growth of skeletal bones and their sexual differences in mice.

An experiment was conducted in 76 mice (3 to 9 weeks of age) to investigate the characteristics in growth of major skeletal bones and their sexual differences. The length of ulna, radius, femur and tibia attained their maximum growth rate at earlier age, and showed no sexual difference in their growth patterns. Scapula length and width, humerus length and os coxae width reached the maximum growth rate at a later age than the forearm and shank, and showed no sexual difference in their growth, although those bones presented larger adult sizes for male than female. The length of vertebrae showed significant sexual differences in their growth patterns and adult sizes, except for lumber vertebrae. A significant sex difference in body weight caused the sexual differences in relative growth of bones to body weight. According to their relative growth to the length of humerus, the skeletal bones could be well grouped into three categories. A significant sexual difference was seen in the relative growth of scapula length. In general, it seemed that the bones growing in a vertical direction grew earlier than the bones growing in a horizontal direction, especially those of the forearm and shank. The results obtained in mice were in good agreement with the findings in pigs.

Developmental patterns of plasma and testicular testosterone in mice from birth to adulthood.

Male mice were raised in cohabitation with females from birth to 90 days. Testosterone was measured every 10 days in plasma and testes. Sex difference in body weight was related to the pre-pubertal increase of testosterone levels in males. The weight of the seminal vesicle was positively correlated with circulating testosterone levels between 1 and 40 days but not between 50 and 90 days. Testosterone concentrations in the plasma and testes were high at birth: 630 pg/ml and 58.0 +/- 17.7 ng/100 mg; they subsequently decreased during the first days of life and remained low until day 20:240 +/- 110 pg/ml and 0.1 +/- 0.03 ng/100 mg. The testosterone levels then increased rapidly between days 20 and 30 and especially between 30 and 40 reaching their maxima: 5770 +/- 1720 pg/ml and 123.7 +/- 18.3 ng/100 mg testis. This increase was transitory and testosterone levels fell after day 40. By 90 days, the testosterone levels, 440 +/- 65 pg/ml and 43.2 +/- 5.5 ng/100 mg testis, were comparable to those measured at birth. Plasma testosterone and age were positively correlated between 1 and 40 days, and negatively between 50 and 90 days. The first fertile matings occurred at age 40 days.

Reproduction, Growth, and Mortality of the Vespertilionid Bat, Eptesicus fuscus, in Kansas

A study was conducted on reproduction, growth, and mortality of Eptesicus fuscus in an area of central Kansas where morphological intergradation has been demonstrated between distinctive eastern and western forms. Observations were made on reproductive chronology and the hypothesis was tested that sexual size dimorphism is evident throughout the period of growth. The parturition period was from late May through the middle of June with most young born in the first week of June. Although the number of implanted embryos exceeded the number surviving to birth, the litter size was two. No significant differences in size or weight were evident between males and females in the prenatal period. Postnatal growth rates in linear dimensions were greater for females than for males. Young bats were foraging at the age of 4 weeks by which time the forearm length had reached 86 and 89 per cent of adult size for males and females, respectively. Adult linear size was attained in approximately 70 days. At birth young bats averaged 3.14 grams or approximately 16 per cent of the postpartum weight of females. Weight gains were nearly linear for the first 6 weeks in both sexes. No sex differences in body weight were evident until young bats were weaned, but after this time females gained weight faster than males. Embryonic resorption, accidents, and predation are considered as factors influencing mortality.

Sex differences in hyperphagia and body weight gains following goldthioglucose-induced hypothalamic lesions in mice

Hypothalamic damage was induced in age-matched male and female albino mice by goldthioglucose injection, and their food consumption and body weight were compared over the following 60-day period. Sex differences in food consumption were also investigated as a function of palatability of food. Results show no significant sex differences in food consumption, although marked sex differences in body weight gain were noted. Female mice with hypothalamic damage gained more body weight than did male mice with hypothalamic damage. These results suggest that obesity induced by hypothalamic damage is probably due to the combined effects of neural and hormonal changes.

Sex differences in body weight following gonadectomy and goldthioglucose injections in mice

Following gonadectomy, male mice of a C57 Black strain show decreased weight gains and females show increased weight gains relative to intact controls. A similar sex difference results from a single injection of goldthioglucose, and after 100 days, female mice overtake the weight gains of the males. It is suggested that these differences are in part due to the drug causing a functional gonadectomy. This is discussed in the light of experiments on the interaction between gonadectomy and goldthioglucose.

Sex differences in body weight and eating: Organization and activation by gonadal hormones in the rat

Female rats injected on the fifth day of life with testosterone propionate (TP) or estradiol benzoate (EB) weigh more in adulthood than control animals injected with oil. If rats are ovariectomized prior to steroid treatment on Day 5, body weight differences in adulthood are reduced and their initial appearance during development is delayed. Neonatal TP or EB treatment increases responsiveness to the weight-promoting effects of androgens in adulthood and decreases adult responsiveness to the weight depressing actions of ovarian hormones. We propose that hormonal stimulation in infancy affects body weight by altering hormonal sensitivity of neural weight regulating mechanisms. Non-neural mechanisms and behavioral effects which might contribute to changes in body weight are also considered. The adult sex difference in body weight is multiply determined by postnatal organizational and activational effects of gonadal hormones as well as by non-hormonal genetic factors and/or prenatal testicular secretions. The sex difference in eating is less subject to early organizing actions of hormones and is primarily attributable to the different hormones secreted by male and female gonads beginning sometime after the end of the neonatal organizational period.

Gonadectomy and ovarian (spleen) grafts and growth of normal male and female mice.

SummaryThis project has been supported in part by funds from the Division of Research Grants and Fellowships of the U. S. Public Health Service and by research grants from Indiana University Graduate School administered by Doctor R. T. Hill.Castrated male mice grew at a slower rate than their normal controls, while the spayed females grew faster than their normal controls. The removal of the gonads reduced the sex difference in body weight. Those animals bearing grafts of ovaries also grew at a faster rate than their normal controls, the difference being significant at the 1% point. Although their growth curve approximated that of the spayed animals, at no time did it exceed it. The growth curve assumed by the weights of the grafted female mice did not parallel that of either the normal males or the castrated males. The differences in the body weight of the grafted females compared with the normal males and the castrated males were significant at the 1% level, the males being heavier in both cases.