Pituitary-Testicular Axis Dysfunction in Spinal Cord Injury

Naftchi, N. E.; Viau, André; Sell, G.; Lowman, Edward W.

doi:10.1007/978-94-011-6305-7_19

Cited by 25 publications

(27 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The observed persistent elevation on plasma gonadotropins agrees with previous reports [ll], as well as with the knowledge that the disturbance in the hypothalamic-pituitary-testicular axis is present for at least 4-6 months after the spinal cord injury [12]. On the contrary, plasma PRL concentrations were more constantly elevated but always below 18 ng/ml only during the first 2-3 months after trauma and thereafter tended towards normal, simultaneously with the attainment of normal androgen levels.…”

Section: Discussionsupporting

confidence: 92%

Diurnal Variations of Pituitary and Testicular Hormones in Paraplegic Men

Cortés-Gallegos

Alonso

et al. 1982

Archives of Andrology

View full text Add to dashboard Cite

The effect of the neuro-spinal cord injury upon testicular physiology was evaluated in six adult paraplegic (PPG) men by measuring the circulating levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), androstenedione, testosterone, and dihydrotestosterone every 4 hr throughout a 24-hr period. Three PPG men were studied within the first 3 months (acute period) and the other three patients 39-79 months (stabilized period) after trauma. Hormonal values were compared with eight age-matched normal adult males. Plasma FSH and LH were constantly above normal concentrations regardless of the sampling time and period of observation, whereas prolactin was higher than normal only during the first two months after trauma, returning to normal afterwards. Plasma androgens were consistently below normal during the first 3 months after injury, and returned toward normal thereafter. There may be a direct relationship between the time elapsed after the spinal cord injury and the plasma androgens concentrations. A possible role of PRL in testicular steroidogenesis is suggested.

show abstract

Section: Discussionsupporting

confidence: 92%

Diurnal Variations of Pituitary and Testicular Hormones in Paraplegic Men

Cortés-Gallegos

Alonso

et al. 1982

Archives of Andrology

View full text Add to dashboard Cite

show abstract

“…27 Since CA has been implicated in the acute-exercise in duced elevations in T then one might expect an exaggerated T response in SCI athletes using boosting since T levels at rest are normal in this population. [18][19][20][21][22][23][24][25] In addition AD is associated with elevated cortisol (C) levels27 which have been suggested as a direct inhibitor of testosterone produc tion.28,29 The SCI athlete thus provides a model to examine the effects of CA and C on the exercise induced increment in testo sterone levels. To date the T response in SCI to acute exercise has not been docu mented.…”

Section: Wheeler 1mentioning

confidence: 99%

Testosterone, cortisol and catecholamine responses to exercise stress and autonomic dysreflexia in elite quadriplegic athletes

et al. 1994

View full text Add to dashboard Cite

Episodes of short high intensity exercise are associated with an increase in circulating total testosterone (T) in men. Mechanisms may include hemoconcen tration, decreased metabolic clearance and/or increased synthesis. Beta-blockade abolishes the T response suggesting a direct beta-adrenergic effect on the testes. Some spinal cord injured (SCI) athletes deliberately induce autonomic dysre flexia (boosting) to enhance performance. Associated with this practice are elevated catecholamine (CA) levels and exaggerated responses to serum cate cholamine levels. Since basal T levels are reported to be normal in the SCI male, the T response to acute high intensity exercise might be expected to be exaggerated by boosting and associated elevated CA levels. The acute exercise T response has not been examined in SCI men to date. To determine whether the increased CA values associated with boosting enhanced the exercise-induced T elevation we measured circulating levels of T, cortisol (C), norepinephrine (NE) and epinephrine (E) before and after maximal exertion and a simulated 7.S km race with and without boosting in eight elite quadriplegic athletes. Maximal incremental exercise and a simulated 7.S km race resulted in a rise in T similar to able bodied men under normal exercise conditions. Under boosted conditions the rise in T was eliminated while NE levels were significantly elevated above unboosted levels. The data may suggest an inhibitory role for CA on T production or release under conditions of extreme stress. Other possible mechanisms include C induced suppression, impaired gonadotropin stimulation of the Leydig cell and CA mediated alterations in gonadal blood supply.

show abstract

“…The studies investigating the effects of SCI on the hypothalamic-pituitary-gonadal (HPG) axis have shown conflicting results. Elevated levels, 23 normal concentration 24,25 and various degrees of decreased serum total and free testosterone 14,15,26,27 have been reported, without an alteration in SHBG 23 or estradiol level. 24,26 It seems likely that the postinjury duration 28,29 and the anatomical lesion level [25][26][27] would account for these conflicting data.…”

Section: Discussionmentioning

confidence: 99%

“…Several pathophysiological mechanisms have been proposed. For some, 14,26,27 the low testosterone level found in chronic patients with SCI could be due to diminished LH and FSH levels. Our results conversely suggest that the primary defect is testicular, with moderate alterations in endocrine function (as shown by low T and normal LH) and exocrine function (germinal cells), as suggested by the high FSH level.…”

Section: Discussionmentioning

confidence: 99%

“…11 Moreover, various hormonal abnormalities -and, in particular, the androgen and growth hormone (GH) deficiency known to be implicated in bone loss and bone turnover alteration in AB men 12,13 -have been highlighted in chronic SCI patients. [14][15][16][17] In the skeleton, GH is known to stimulate the proliferation and the differentiation of osteoblasts and to increase the synthesis of type I collagen, alkaline phosphatase and osteocalcin. 18 GH modulates the osteoblast production of insulin-like growth factor-I (IGF-I) which is an important mediator for GH-induced bone cell proliferation.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The role of androgens or growth factors in the bone resorption process in recent spinal cord injured patients: a cross-sectional study

et al. 2006

View full text Add to dashboard Cite

Study design: This cross-sectional study compared the androgen and growth factor profiles and the bone turnover of patients with spinal cord injury (SCI) versus able-bodied controls (AB). Objective: Determine whether androgens, GH, or either IGF-I or IGFBP-3, are implicated in bone turnover alteration in patients with recent SCI. Setting: Propara Center, Montpellier, France. Methods: In all, 16 men (31.3 years) with complete SCI, seven paraplegics and nine tetraplegics, who had sustained injury an average of 3 months earlier, and 12 AB who served as controls (27.5 years) participated. Androgens, growth hormone and its mediators were investigated. The bone resorption process was evaluated by urinary and plasma type I collagen C-telopeptide (CTXu, CTXp), while bone formation was evaluated by osteocalcin (OC) and bone alkaline phosphatase. Results: Total testosterone (TT) and the free androgen index (FAI) were significantly lower in the SCI patients, whereas FSH was significantly higher (Po0.05). These hormonal variations were not related to the level of neurological lesion. There was no significant difference in GH, IGF-I, or IGFBP-3 levels. CTXu and CTXp indicated high bone resorption activity in the SCI patients (Po0.05). Regarding bone formation markers, only OC was affected by neurological lesion (Po0.05). Basal hormone levels did not correlate with markers of bone turnover. Conclusion: The high bone resorption process observed in SCI patients did not seem directly related to testicular endocrine abnormalities or an altered growth factor profile. Nevertheless, the reduced TT and FAI levels could be aggravating factors in the development of acute bone loss.

show abstract

Pituitary-Testicular Axis Dysfunction in Spinal Cord Injury

Cited by 25 publications

References 26 publications

Diurnal Variations of Pituitary and Testicular Hormones in Paraplegic Men

Diurnal Variations of Pituitary and Testicular Hormones in Paraplegic Men

Testosterone, cortisol and catecholamine responses to exercise stress and autonomic dysreflexia in elite quadriplegic athletes

The role of androgens or growth factors in the bone resorption process in recent spinal cord injured patients: a cross-sectional study

Contact Info

Product

Resources

About