Differentiation of male hypogonadotropic hypogonadism and XXXX by pulsatile administration of gonadotropin-releasing hormone.

@entity1 @entity251 @entity1640 @entity1050 @entity1175 @entity1176 @entity9027 @entity2671
It is not possible to differentiate reliably between male idiopathic @entity1640 ( @entity1640 ) and severe @entity1175 ( @entity1050 ) on the basis of a standard @entity1176 bolus test (GBT) or other known endocrine or clinical parameters. Therefore, we studied the response of 17 hypogonadal @entity1 , 8 with a diagnosis of @entity1640 (age, 15.5-41; bone age, 12.5-19 yr; testes, 1-4 ml) and 9 with @entity1050 (age, 14.5-20; bone age, 11-15 yr, testes, 2-10 ml) to pulsatile @entity1176 stimulation. Basal and peak LH and FSH levels after a single dose of @entity1176 greatly overlapped between the two groups. In each @entity1 , a spontaneous nocturnal plasma profile of LH and FSH, sampled every 20 min, was followed by a pulsatile @entity1176 stimulation (5 micrograms iv every 90 min) via a portable minipump for 36 h. Before and after this pulsatile @entity1176 stimulation, a GBT (60 micrograms/m2 iv) was performed and plasma LH, FSH, @entity251 , @entity2671 , and @entity9027 were measured. Pulse analysis revealed 0-5 spontaneous nocturnal LH peaks in the @entity1050 @entity1 but only one in all of the @entity1640 @entity1 . During the 36 h of pulsatile @entity1176 , mean LH and FSH levels were significantly higher (P less than 0.0001) than during the spontaneous nocturnal profile in all @entity1 (except 1 from each group for LH). The GBT after pulsatile stimulation caused significantly higher (P less than 0.001) LH increments in @entity1050 than in @entity1640 @entity1 , with no overlap between the two groups (range, 4.1-15.6 in @entity1050 vs. 0.8-2.4 mIU/ml in @entity1640 ). Plasma @entity251 rose significantly (P less than 0.01) during pulsatile @entity1176 from 67 to 155 ng/dl (median) in the @entity1050 @entity1 , but did not change in the @entity1640 group (21 to 22.5 ng/dl). Plasma @entity2671 and @entity9027 did not rise in either group. We conclude that, in contrast to other parameters investigated so far, the LH increment in the second GBT after 36 h of pulsatile @entity1176 allows clear-cut differentiation between @entity1050 and @entity1640 . These results indicate significantly lower pituitary LH reserve in @entity1 with permanent @entity1640 after short term priming of the pituitary by pulsatile @entity1176 administration.
