In humans, as in all mammalian males, Leydig cells are the main source of the androgenic hormone, testosterone, which is essential for male sexual differentiation, gamete production and maturation, and development of secondary sexual characteristics. In this chapter, the development, steroidogenic function, and regulation of human Leydig cells are summarized. Clinical aspects of androgen secret...

The paper provides comparative data concerning sleeping distance in relation to sexual state and hierarchical dominance in the Arctic blue fox. Increasing levels of vulval swelling and electrical resistance of vaginal tract were inversely related to sleeping distance between the highest-ranking male and each female on heat. A mating pair typically slept no further than 50 cm from each other. On...

Male sexual differentiation is the result of complex mechanisms involving developmental genetics and endocrinology. Formation of the bipotential gonads and subsequently the testes is dependent on a series of sex chromosome-linked and autosomal genes. The testes secrete both peptide and steroid hormones essential for the formation of internal and external genitalia. Hormone action is mediated vi...

In recent years, the study of human behavior has been greatly enriched by advances in the biologic and physiologic sciences and the concomitant development of organic methods, especially drugs, to alter and to treat cognitive, affective, and behavior disorders. In particular, recent refinements in the techniques for measuring plasma hormone levels have prompted increased interest in the psychoe...

INTRODUCTION Few studies have examined how sexual arousal influences healthy premenopausal women's hormones, limiting our understanding of basic physiology and our ability to transfer knowledge from clinical and nonhuman populations. AIM To examine how sexual arousal and steroid hormones (testosterone [T], cortisol [C], estradiol [E]) were linked, to see whether hormone levels influenced and/...

Water molds of the genus Phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in Phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a Phytophthora mating horm...

In 15 consecutive patients with slipped capital femoral epiphysis we recorded height, weight and skeletal maturity. Sexual maturity was assessed clinically and biochemically, and Harris's hypothesis that there is an increased ratio of serum growth hormone to oestrogen was tested in comparison with 15 age and sex matched controls. We found no difference in skeletal or sexual maturity between the...

Increased demands of the seafood market have led to rapid growth in crustacean aquaculture production various parts world. Therefore, an expansion knowledge reproductive biology crustaceans has become more important. Hormones released from androgenic gland (AG) are liable for both separation primary and secondary sexual features behavior. AG removal male causes a transformation intersex animals...

INTRODUCTION Chronic renal failure is associated with endocrine abnormalities, which in some cases cause polyendocrinopathy responsible for the symptoms and complications. The consequence of secondary hyperparathyroidism is not only bone disease but may be cardiovascular disorders, peripheral nerve damage and impact on the level of sex hormones. THE AIM To evaluate the interactions between pa...

background: diminished libido and sexual dysfunction are unusually common among male epileptic patients. the most important etiologic factor may be antiepileptic drugs (aeds)-induced androgen deficiency. we compared reproductive hormone levels among men with epilepsy taking various aeds and normal controls. methods: subjects were 59 male epileptic patients who aged 24 ± 5 years. they had been r...