C. Grobbelaar

O-8 Kisspeptina new era in sports endocrinology?

Athletic Amenorrhoea is a fairly common and invariably performance-limiting condition seen in female endurance athletes, dancers and gymnasts, notably those of the “low body weight” genera (up to 60% are affected). The hypothalamic amenorrhoea in athletes exists as a continuum preceded by a stressor exercise stress; reduced energy availability) followed by lowered gonadotropin releasing hormone (GnRH) stimulation, diminished gonadotropic hormone release, finally resulting in reduced steroid hormone production. The treatment of athletic amenorrhoea focuses largely on reversing the energy imbalance, reducing training and, if necessary supplementing with exogenous sex steroids. The latter proves less popular for use in younger athletes. Gonadotropin administration has thus far been the treatment of choice to restore reproductive function. The use of androgenic anabolic steroids (AAS), synthetic derivatives of testosterone, has been the subject of concern in the sporting industry for decades. AAS’s have been shown to enhance androgen receptor expression in the hypothalamus, thus invoking a negative feedback response on GnRH and luteinizing hormone (LH) release giving rise to anabolic steroid-induced hypogonadism (ASIH). This diminution in gonadotrophic activity has been shown to have a deleterious effect on sexual behaviour and reproduction in both animal and human models. Various case studies have been presented to highlight the long term consequences of both clinical and aberrant supraphysiological doses of exogenous steroids as seen in chronic users and abusers. The treatment of ASIH entails restoration of the hypothalamic-pituitary-testicular axis (HPT) to re-establish endogenous testosterone production and action. Thus the increased use of AAS’s in adolescents and young adults have highlighted the need for control. The control hereof does not only seek to negate the in-competition advantage in athletes but to deter the sometimes irreversible behavioural and reproductive dysfunction encountered in users. Kisspeptins are a group of peptidergic neurohormones that are able to stimulate the hypothalamic-pituitary-gonadal (HPG) axis and the secretion of GnRH, LH, follicle stimulating hormone (FSH), estradiol and testosterone in a dose-dependent manner. They act via the G-protein coupled receptor ((GPR-54); (KISS1R)) and are encoded by the KISS1 gene. Overtraining and reduced calorie intake in athletic females and anabolic steroid use has been shown to diminish LH pulse frequency and secretion via the diminution of GnRH expression. Studies done in males and females with hypothalamic hypogonadism who received intravenous and subcutaneous kisspeptin analogues showed a dose dependent increase in mean LH and LH pulse frequency. Kisspeptin administration has been shown to maintain 2-fold elevations in LH secretion despite elevated testosterone in males. Therefore, it is proposed that exogenous administration of Kisspeptin should yield an increase in LH secretion and pulsatility to a much greater extent. This has staggering implications, as kisspeptin could possibly be used in provocative testing with regards to the use of AAS in athletes. It is likely that Kisspeptin administration will restore LH pulsatility in these athletes and reverse the hypogonadism and effects thereof, thus offering a newer treatment option. This allows for a novel therapeutic mechanism by which the effects of athletic and steroid-induced hypogonadism can be corrected. References Ackerman, KE, Slusarz K, Guereca G, Pierce L, Slattery M, Mendes N, Herzog DB, Misra M. Higher Ghrelin and Lower Leptin Secretion is Associated with Lower LH Secretion in Young Amenorrheic Athletes Compared with Eumenorrheic Athletes and Controls: Articlesin Press. Am J Physiol Endocrinol Metab. doi:10.1152/ajpendo.00598.2011 Clark AS, Henderson LP. Behavioural and physiological responses to anabolic-androgenic steroids. Neurosci Biobehav Rev 2003;27:413–436. George JT, Veldhuis JD, Roseweir AK, Newton CL, Faccenda E, Millar RP, et al. Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men. J Clin Endocrinol Metab 2011;96(8):E1228–E1236. Ker JM, Congeni JA. Anabolic-androgenic steroids Use and abuse in paediatric patients: Paediatric Clinical N AM 2007;54:771–85. Manuel Tena-Sempere. GPR54 and kisspeptin in reproduction. Hum Reprod. 2006;12(5):631–639. doi:10.1093/humupd/dml023 Millar RP, Roseweir AK, Tello JA, Anderson RA, George JT, Morgan K. Kisspeptin antagonists: Unravelling the role of kisspeptin in reproductive physiology. Brain Res 2010;1364:81–9. Miller KK. Endocrine dysregulation in anorexia nervosa update. J Clin Endocrinol Metab 2011;96(10):2939–49.

The correlation between the health-related fitness of healthy participants measured at home as opposed to fitness measured by sport scientists in a laboratory

Background: Fitness is defined in the health context as a state of good health or physical condition, primarily as a result of exercise and proper nutrition. Conventional methods of measuring fitness are expensive, time consuming and require specialised methods. There is a need for noninvasive, fast methods of assessing health-related fitness and activity in athlete and non-athlete populations. The aim of this study was to establish any correlation between participants’ self-assessed health-related fitness (HRF) index and the HRF index determined by sports scientists, as well as the laboratory-assessed HRF index and maximum oxygen uptake (VO2max) determined by sports scientists via direct methods in a laboratory, and finally, to determine any potential correlation between an activity-recall questionnaire (Kasari) and VO2max. Method: The participants consisted of 169 male and female volunteers between the ages of 18 and 55 years, taking neither supplements nor medication. The University of Pretoria’s HRF index protocol was first carried out by participants on their own at home, and then in the laboratory under the supervision of sport scientists. The complete datasets of 150 participants were statistically analysed to establish correlations. Results: The results indicated highly significant and substantial correlations (ρ = 0.696, p < 0.001) between the participants’ self-assessed HRF index and measurements by the sports scientists. There were moderate correlations between the laboratory-assessed HRF index and the direct VO2max (ρ = 0.512, p < 0.005), as well as the indirect VO2max (ρ = 0.588; p < 0.001). A significant correlation was found between the self-assessed HRF index and the indirect VO2max (ρ = 0.454; p < 0.001). The Kasari questionnaire correlated only weakly with the indirect VO2max (ρ = 0.278, p < 0.002) and not at all with the direct VO2max (ρ = 0.072, p < 0.731). Conclusion: Indications are that this test protocol may be conducted at home by individuals, without supervision, to determine exercise ability or fitness, or to monitor changes in physical fitness, thereby limiting expenses and costs.

The influene of an intense training programme on Cardio Stress Index

Mense ondervind baie stressors in hul alledaagse lewe, wat ‘n groot uitwerking het op daaglikse funksionering. Kardio Stres-indeks (KSI) is ‘n nie-indringende mate van die stres wat die hart ervaar. KSI (uitgedruk as ‘n persentasie) berekeninge word gebaseer op die duur van die QRS kompleks, hart tempo, ritme en standaardafwyking van die RR-interval (RRSD) spesifieke parameters.