-
Views
-
Cite
Cite
A. G. H. SMALS, P. W. C. KLOPPENBORG, G. F. E. PIETERS, W. H. L. HOEFNAGELS, R. M. LEQUIN, Th. J. BENRAAD, Modulation of the Gonadotropin Response to Constant Luteinizing Hormone-Releasing Hormone Infusion by Acute and Chronic Testosterone Administration in Klinefelter's Syndrome, The Journal of Clinical Endocrinology & Metabolism, Volume 48, Issue 1, 1 January 1979, Pages 148–152, https://doi.org/10.1210/jcem-48-1-148
Close - Share Icon Share
Abstract
Constant infusion of 0.4 μg LRH/min for 4 h elicited a biphasic response of LH, not of FSH, in four patients with Klinefelter's syndrome, with a first peak at 52 ± 9 min, a subsequent fall, and a second peak at 172 ± 37 min after initiation of the infusion.
Constant LRH and simultaneous testosterone infusion at twice the physiological production rate delayed the initial LH rise by 15 min and blurred the biphasic response, but did not influence total LH secretion during the infusion period. Total FSH secretion decreased in two of the patients.
Chronic testosterone therapy for 5 months (100 mg im weekly) reduced the elevated LH levels in three of the patients by 82 ± 13%, but scarcely influenced LH levels in the fourth patient despite a 10-fold plasma testosterone increase. Long term testosterone treatment almost completely abolished the initial LH rise to constant LRH infusion in the three patients with suppressed LH secretion, but not in the fourth patient with nonsuppressible LH levels. The second LH rise was enhanced in at least two of the patients. Total FSH release decreased in two patients.
It was concluded that in Klinefelter's syndrome, acute testosterone administration does not seem to influence the readily releasable pituitary LH pool. On the other hand, chronic testosterone therapy depletes this first LH pool but does not seem to diminish the second rise in LH, which presumably represents de novo synthesis, in most patients. Refractoriness to testosterone feedback inhibition at the hypothalamic level might explain persistence of the first readily releasable LH pool in one of the patients with Klinefelter's syndrome.
