Two men with PRL-secreting pituitary adenomas and hypogonadism were studied before and repeatedly after transsphenoidal adenomectomy. Serum PRL levels were elevated (220 and 300 ng/ml), with no rise after perphenazine or TRH administration. Serum testosterone levels were low (180 and 155 ng/dl) but increased to 800 and 520 after hCG administration. Serum gonadotropin levels were low normal. Clomiphene treatment in patient 2 was not associated with an appreciable increase in FSH, LH, or testosterone. One patient had a normal sperm count, while the other was azospermic. One week after surgery, serum PRL levels were normal, yet serum testosterone remained low. A gradual and steady rise in the serum testosterone level was noted during the postoperative period, reaching normal levels in 8 and 10 weeks. Clinical improvement paralleled the steady rise in the serum testosterone level. Repeat clomiphene administration in patient 2 resulted in a normal rise in serum FSH, LH, and testosterone 13 weeks after surgery. Sperm count increased from 0 to 22.3 million/ml in patient 2. The serum PRL response to the adminstration of TRH was subnormal (<50% increase) in both patients 1 week after surgery. This response became normal (>100% increase) at 2 weeks in patient 1 and remained so at 4 and 13 weeks. However, in patient 2, this response was still subnormal (80% increase) at 2 weeks but was normal at 5 and 13 weeks. In contrast to PRL, the serum TSH response to TRH administration remained normal 1 week after surgery and was not altered thereafter. PRL responses to perphenazine and L-dopa as well as the rest of the pituitary functions were normal in both patients 13 weeks after surgery. We conclude that the recovery of the hypothalamic-pituitarygonadal axis takes several weeks to occur after the correction of hyperprolactinemia. The recovery of normal lactotroph responsiveness from the inhibition caused by chronic hyperprolactinemia takes 2–5 weeks to occur.
All Science Journal Classification (ASJC) codes
- Endocrinology, Diabetes and Metabolism
- Clinical Biochemistry
- Biochemistry, medical