Mild Androgen Insensitivity Syndrome: The Current Landscape

ObjectiveMild androgen insensitivity syndrome (MAIS) belongs to the androgen insensitivity syndrome (AIS) spectrum, an X-linked genetic disease that is the most common cause of differences in sex development. Unfortunately, AIS studies mainly focus on the partial and complete phenotypes, and the mild phenotype (MAIS) has been barely reported. Our purpose is to explore the MAIS facets, clinical features, and molecular aspects.MethodsWe collected all reported MAIS cases in the medical literature and presented them based on the phenotype and molecular diagnosis.ResultsWe identified 49 different androgen receptor (AR) mutations in 69 individuals in the literature. We compared the AR mutations presented in individuals with MAIS with AR mutations previously reported in other AIS phenotypes (partial and complete) regarding the type, location, genotype-phenotype correlation, and functional studies.ConclusionThis review provides a landscape of the mild phenotype of AIS. Most patients with MAIS present with male factor infertility. Therefore, AR gene sequencing should be considered during male factor infertility investigation, even in males with typically male external genitalia. In addition, MAIS can be part of other medical conditions, such as X-linked spinal and bulbar muscular atrophy (Kennedy disease).     

The effects of running activity on the reproductive axes of rodents

Access to a running wheel causes gonadal recrudescence in Syrian hamsters whose reproductive axes have been suppressed by housing them under short day lengths (Borer et al. 1983). The first experiment tested the generality of this phenomenon in a population of rodents that is genetically heterogeneous for reproductive photoresponsiveness. Male meadow voles (Microtus pennsylvanicus) of the two extreme phenotypes — reproductively photoresponsive and non-responsive — were either provided with a running wheel or housed without one. After 4 weeks with a wheel, the responsive voles had recovered full reproductive function, while the reproductive axes of responsive voles housed without wheels remained suppressed. Three experiments queried whether the use of a wheel would have reproductively stimulative effects in other rodents. First, intact male mice given access to wheels showed no increase in testis size when compared to mice housed without wheels. Likewise, locomotor activity had no effect on male rats whose testes were partially regressed in response to testosterone implants or on female mice whose estrous cycles were pheromonally suppressed by housing them in groups. Thus the neuroendocrine pathway used by locomotor activity to enhance the secretion of gonadotropin is specifically allied with the pathway used by photoperiod to control GnRH secretion.Abbreviations GnRH gonadotropin-releasing hormone - LH luteinizing hormone     

Gonadal Influences on the Sexual Differentiation of Monoamine Oxidase Type A and B Activities in the Rat Brain

Abstract: The sex-dependent differentiation of monoamine oxidase (MAO) in the hypothalamus of 60-day-old, Charles River rats was found to involve only type A (MAO-A), and not type B (MAO-B) enzyme. In vivo inhibition of type A by clorgyline, and type B by (−)deprenyl, however, tended to decrease the specific activity of both types of MAO to a smaller extent in the female than in the male hypothalamus. When masculinization was prevented by neonatal administration of estradiol (E) to males, hypothalamic MAO-A and MAO-B activities increased in both control and MAO-inhibited rats. Androgenization of females, however, had little effect on the MAO activity. Whereas the effects of neonatal estrogenization were attributable neither to a direct influence of E nor to a sexual difference in the peripheral clearance of the MAO-inhibitor used, single, high doses of steroids to adult, but not to newborn rats, did acutely affect the kinetics of MAO-A. The activity of MAO-A was also decreased by high concentrations of E or TS in vitro. The imprinting for patterns of hypothalamic MAO-A and MAO-B in the two sexes results, probably, from genetic predetermination. Neonatal changes in the homeostasis of gonadal hormones may result in type-MAO nonspecific effects in adulthood, whereas the short-term effects of high concentrations of steroids may be selective for the A form.     

Endocrine control of spermatogenesis in primates

Control of primate spermatogenesis is reviewed in terms of endogenous regulatory mechanisms and endocrine approaches to contraception and treatment of infertility. The role of gonadotropins and steroid hormones in maintaining spermatogenesis in primates is incompletely understood because A) hormonal interactions are complex, and B) most studies have used rodents rather than primates. Feedback control, interaction of LH and testosterone, the role of androgen, androgen in secondary sex organs, regulation of receptor proteins, roles of prolactin and growth hormone, and the breakdown and modification of the endocrine control mechanism are reviewed. The treatment of infertility with GnRH, gonadotropins, and androgen is discussed. Information is included on contraception research using the following methods: immunization against GnRH, use of GnRH analogs, immunization against gonadotropins, induced suppression of FSH secretion or action, and steroid suppression of spermatogenesis. The importance of studying testicular steroid metabolism in primates is stressed. Significant advances in the understanding of endocrine control of spermatogenesis have been made in recent years, but no primate species have been thoroughly studied. Variability between species in endocrine control mechanisms is an important factor in selecting primate models, and it is clear that such models can be valuable in the development of male contraceptives.     

Male behavior through the breeding season in Saimiri boliviensis boliviensis

The Bolivian squirrel monkey (Saimiri boliviensis boliviensis) is a seasonal breeder. Male squirrel monkeys show distinct morphological and behavioral changes prior to and during the breeding season. A “fatting syndrome” includes increased body weight, increased levels of androgens, and in the Bolivian subspecies, an increasingly active role in the social organization of the group. In this study, the behavior of ten adult male Bolivian squirrel monkeys was analyzed over a 6-month period prior to, during, and after the breeding season. Each was housed as the only adult male in a breeding unit with six to ten adult females and one juvenile male. Employing a principle components method, 11 behavioral clusters were generated from 27 responses. Their activity clusters were identified as follows: sexual activity that showed a peak around the time of peak conceptions; excitatory activity that was initially high but decreased throughout the breeding season; and maintenance activity that did not change across the breeding season. The changing social behavior of the male squirrel monkey parallels physiological changes and is correlated with changing androgen levels.