Search results for "Secondary sex characteristic"
showing 6 items of 6 documents
Gonadotropic Therapy in Men with Hypogonadotropic Hypogonadism
1984
Many therapeutic regimens, differing in dose and duration, have been employed in the treatment of hypogonadotropic hypogonadism. This study presents the results from a regimen of hCG plus hMG plus testosterone combined treatment in 15 patients affected by selective hypogonadotropic hypogonadism. The patients were homogeneous in age (16–23 years), testicular size, aspermia, absence of prior hormonal treatment, and normal karyotype. They were administered 5000 IU of hCG plus 75 IU of hMG twice a week for two months and a single dose of depo-testosterone (250 mg) in the third month. This therapeutic plan was carried out continuously for eight three-month cycles (24 months). Sexual maturation a…
Genetic and environmental influences on pubertal timing assessed by height growth
2008
Secular trends towards earlier puberty, possibly caused by new environmental triggers, provide a basis for periodic evaluation of the influence and interaction of genetic and environmental effects on pubertal timing. In such studies, a practical marker that reflects timing of puberty in both genders needs to be used. We investigated genetic and environmental influences on pubertal timing by using change in the relative height between early and late adolescence (HD:SDS, height difference in standard deviations) as a new marker of pubertal timing. HD:SDS correlated well with age at peak height velocity in a population of men and women with longitudinal growth data. In 2,309 twin girls and 1,8…
Can female preference explain sexual dichromatism in the pied flycatcher, Ficedula hypoleuca?
1990
How important female choice is for the evolution of male secondary sexual characteristics is controversial. Two field and one laboratory experiment, using the pied flycatcher, were performed to test the female choice aspect of sexual selection. In addition, non-manipulative data from 5 years are presented. The observational data suggest a slight preference for dark males by females but in field experiments in which males had territories at random sites (i.e. they did not choose a territory) or the colour of concurrently arriving males was altered, there was no preference for darker ones. Similarly, oestradiol-treated females did not prefer black or brown males in the laboratory. Thus, there…
Facial attractiveness in men provides clues to semen quality
2003
Abstract Facial attractiveness has been related to health in both men and women. Certain psychological, physiological, and secondary sex characteristics have been used as accurate markers of hormonal and developmental health. The main objective of this study was to investigate the capacity of women to select males of high reproductive quality based on their facial attractiveness. A total of 66 males were included in the study. Each of them provides a semen sample, and frontal and lateral photographs were taken. Semen analysis was made according to standard WHO (1999) guidelines for morphology, motility, and concentration. Moreover, a Sperm Index (SI) was calculated as the principal componen…
No evidence of androgenic hormone from the testes of the glowworm, Lampyris noctiluca.
2005
The widely accepted concept, stating that insects have no true sex hormones, and that primary as well as secondary sex characteristics are controlled by the genetic inventory of each single cell, is challenged by the report of Naisse, J. [1966a. Controle endocrinien de la differenciation sexuelle chez l'Insecte Lampyris noctiluca (Coleoptere Malacoderme Lampyride). I. Role androgene des testicules, Arch. Biol. Liege, 77, 139-201] on the discovery of an androgenic hormone in the glowworm, Lampyris noctiluca. This case is of special interest, since it may point to an ancestral mode of sex differentiation in arthropods, considering that androgenic hormones have been discovered and characterize…
The role of juvenile hormone in immune function and pheromone production trade-offs: a test of the immunocompetence handicap principle
2003
The immunocompetence handicap hypothesis postulates that secondary sexual traits are honest signals of mate quality because the hormones (e.g. testosterone) needed to develop secondary sexual traits have immunosuppressive effects. The best support for predictions arising from the immunocompetence handicap hypothesis so far comes from studies of insects, although they lack male-specific hormones such as testosterone. In our previous studies, we found that female mealworm beetles prefer pheromones of immunocompetent males. Here, we tested how juvenile hormone (JH) affects male investment in secondary sexual characteristics and immune functions in the mealworm beetle, Tenebrio molitor. We inje…