Is there a physiological role for gonadotrophin oligosaccharide heterogeneity in humans? III. Luteinizing hormone heterogeneity: a medical physiologist's perspective.
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Clinical evidence for a physiological impact of luteinizing hormone (LH) isoforms includes their unequal in-vitro bioactivity and altered in-vivo LH kinetics. For example, alkaline LH isospecies emerge in an oestrogen-rich milieu, and show greater bioactivity in vitro along with more rapid metabolic removal in vivo. More acidic LH isotypes are predominant in eugonadal men with end-stage renal failure and in postmenopausal women. The relevance of changes in charge distribution in puberty to sexual maturation is not clear. Molecular LH variants may be associated with decreased testis size and reduced linear growth in boys, menstrual irregularity and/or subfertility in women, and possibly protect against polycystic ovarian syndrome (PCOS). This article summarises the provisional physiological implications of LH isotypes based on current evidence. (+info)
Trends in pubertal development in Europe.
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The secular changes in growth and maturation can be seen as indicators of socio-economic and health status. In most European countries the age of onset of puberty and of menarcheal age has been decreasing during the past few decades. The duration of puberty seems also to decrease, though few studies provide sufficient data to support this postulation. The four Dutch nationwide growth surveys are useful examples assessing the secular trend in pubertal development over the past 45 years. Genetic and environmental factors contribute to the secular changes. Environmental factors seem to be the most important. Recently, attention has been given to substances with oestrogen-like actions that are present in nutrients. The possible role of these substances in growth and maturation is discussed. (+info)
Morphology of the temporomandibular joint in skeletal class iii symmetrical and asymmetrical cases: a study by cephalometric laminography.
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The aetiology of asymmetric growth in the mandible is not well understood. Previous studies have indicated that the functional lateral shift of the mandible in the period of prepubertal growth may translate to a true skeletal asymmetry, exclusively in skeletal Class III malocclusion. This asymmetry develops more characteristic features during the pubertal and post-pubertal growth periods. Early correction of a functional lateral shift of the mandible is recommended. The purpose of this study was to examine the relationship between the morphology of the temporomandibular joints and asymmetry in skeletal Class III malocclusion in adult female patients. Cephalometric and laminographic findings in 36 asymmetric skeletal Class III patients with a lateral shift of mandible (group 3) were compared to those of 25 symmetric skeletal Class I patients (group 1) and the same number of symmetric skeletal Class III malocclusions (group 2). All the patients had received no orthodontic treatment. The results showed that the TMJ of the side to which the mandible shifted showed a significantly narrower and shorter shape of the condyle head, smaller superior condylar space, and steeper eminence than those of the unshifted side. (+info)
Leptin levels show diurnal variation throughout puberty in healthy children, and follow a gender-specific pattern.
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OBJECTIVE: To investigate the levels and diurnal rhythm of serum leptin in healthy children, and to investigate the association between leptin levels and sex steroids. METHODS: Four girls and four boys, all healthy volunteers, were followed longitudinally throughout puberty. Their chronological ages ranged from 8.7 to 19.5 years, and body composition, expressed as weight-for-height standard deviation scores (SDS), ranged between -1.7 and +2.4. Serum leptin, oestradiol and testosterone concentrations were measured by radioimmunoassay at 1000, 1400, 1800, 2200, 0200 and 0600 h. RESULTS: In all girls and boys, both prepubertally and during pubertal development, serum leptin levels increased during the night, with no difference in relative peak amplitude. In boys, the leptin concentrations increased until the initiation of puberty and then declined, whereas in girls, the concentrations increased throughout puberty. The inter-individual variation in mean leptin levels among girls decreased to 11% at the time of menarche. A positive correlation was found for both oestradiol and testosterone versus leptin in girls throughout puberty (r=0.64 and r=0.71 respectively, P<0.001). A negative correlation was found between leptin and testosterone in boys in mid- and late puberty (r=-0.66, P<0.01). No correlation was found between oestradiol and leptin in boys or between testosterone and leptin in pre- and early pubertal boys. CONCLUSION: Serum leptin concentrations show diurnal variation throughout pubertal development in both girls and boys. The changes in leptin levels during puberty follow a gender-specific pattern, probably due to an influence of sex steroids on leptin production. (+info)
Partial isolation of a pheromone accelerating puberty in female mice.
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The sexual development of female mice is accelerated by exposure to an adult male or to male urine. The component of the urine responsible for this effect is androgen-dependent, heat labile, nondialysable, precipitatable with ammonium sulphate, and is not extractable in ether. These results indicate that the pheromone causing accelerated sexual development is associated with a protein component of male urine. Tests of the active fraction after digestion with proteolytic enzymes suggest that the pheromone may be a portion of a protein or a substance bound to a protein. (+info)
Testicular function following chemotherapy.
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Testicular dysfunction is a common long-term sequela of cytotoxic chemotherapy used in the treatment of many malignancies. The degree to which testicular function is affected is dose- and agent-dependent. The impact on germinal epithelial function of standard multi-agent regimens used in the treatment of lymphomas has been widely studied. Procarbazine-containing regimens result in azoospermia in the vast majority of patients, but much lesser degrees of long-term gonadotoxicity are apparent with the newer forms of chemotherapy. High-dose chemotherapy used as preparation before bone marrow transplant is also associated with irreversible germinal epithelial failure in the majority of men. Treatment of testicular cancer with cisplatin and carboplatin regimens leads to temporary azoo- and oligozoospermia in most men, with a recovery to normospermia in 80% by 5 years. There is also evidence of mild Leydig cell impairment in a proportion of men treated with cytotoxic agents, although the clinical significance of this is not clear. Several methods of preserving testicular function during potentially sterilizing treatment have been considered. At present, sperm banking remains the only proven method, although hormonal manipulation to enhance recovery of spermatogenesis and cryopreservation of testicular germ cells are possibilities for the future. (+info)
Growth hormone and gonadotropin-releasing hormone analog therapy in haploinsufficiency of SHOX.
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We report on GH (0.5 IU or 0.17 mg/kg/week) and GnRH analog (GnRHa, 60 microg/kg, every 4 weeks) therapy in SHOX haploinsufficiency. Case 1 was a 46,XY boy with microdeletion of the Y chromosomal pseudoautosomal region. At 7 years of age, he exhibited short stature (-3.9 SD) with a reduced growth rate (3.8 cm/year), short 4th metacarpals, and mild Madelung deformity. GH therapy resulted in a marked increase in height velocity (10.7 cm/year in the first year). Case 2 was a 46,XX girl with a heterozygous nonsense mutation of SHOX (C674T). At 6 years of age, she presented with short stature (-3.3 SD) with a low height velocity (4.0 cm/year). GH therapy caused a moderate increase in height velocity (6.6 cm/year in the first year and 6.0 cm/year in the second year) before puberty. Because of breast development, she received GnRHa from 9 8/12 years of age. At 10 10/12 years of age, she had mild shortening and borderline curvature of radius. Case 3 was a girl with a 46,X,der(X)t(X;2)(p22.3;p21) karyotype. She was treated with GH from 6 to 14 years of age, and also with GnRHa from 12 to 15 years of age. Her height remained around mean -4 SD, with no discernible alteration of height velocity. At 17 years of age, she had short stature (-4.1 SD), bilateral cubitus valgus, Madelung deformity, and full breast development. The results suggest that GH therapy may have variable statural effects in SHOX haploinsufficiency as in most disorders including Turner syndrome, and that GnRHa therapy after pubertal entry may be insufficient to prevent the development of skeletal lesions such as Madelung deformity. (+info)
Hypothalamic-pituitary-ovarian dysfunction after prepubertal chemotherapy and cranial irradiation for acute leukaemia.
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BACKGROUND: We assessed adult hypothalamic-pituitary-ovarian function following treatment with chemotherapy and cranial irradiation for childhood acute lymphoblastic leukaemia. METHODS: The patients (n = 12) had median age at diagnosis of 4.7 years, and at assessment of 20.8 years. They collected a daily urine sample over two to five consecutive menstrual cycles (total of 41 cycles) for analysis of LH and steroid excretion. Blood sampling and ovarian ultrasound examination was performed in the early follicular phase. Sixteen healthy women with regular menstrual cycles were recruited as controls. RESULTS: Urinary LH excretion was significantly lower in patients throughout the cycle, particularly during the LH surge (P < 0.0001). The length of the luteal phase was significantly shorter in patients than in normal controls (12.2 +/- 0.3 versus 13.6 +/- 0.4 days, P = 0.01) with a high prevalence of short (< or =11 days) luteal phases (15/39 cycles). Luteal phase pregnanediol excretion was slightly but not significantly lower. Follicular and luteal phase excretion of oestrone was lower in patients than in controls (P = 0.01). Early follicular phase plasma oestradiol was also lower in the patient group (P = 0.032) although LH, FSH, inhibin A and B concentrations were similar. CONCLUSIONS: These data indicate that treatment for childhood leukaemia results in subtle ovulatory disorder in some patients, probably related to cranial irradiation. Follow-up of these women is required to detect any effect on reproductive potential. (+info)